User’s Manual QMS 100 Series Gas Analyzer 1290-D Reamwood Avenue Sunnyvale, CA 94089 U.S.A. Phone: (408) 744-9040, Fax: (408) 744-9049 Email: info@thinkSRS.com ▪ www.thinkSRS.com Copyright © 2000 All Rights Reserved Version 3.
Certification Stanford Research Systems certifies that this product met its published specifications at the time of shipment. Warranty This Stanford Research Systems product is warranted against defects in materials and workmanship for a period of one (1) year from the date of shipment. Service For warranty service or repair, this product must be returned to a Stanford Research Systems authorized service facility. Some components may be serviceable directly from the supplier.
iii Table of Contents Safety ........................................................................................................................................................................... iv Symbols .........................................................................................................................................................................v Fast Start .....................................................................................................................
iv Safety WARNING Hazardous voltages, capable of causing injury or death, are present in this instrument. Use extreme caution whenever the instrument cover is removed. Always unplug the unit while removing the cover. Ventilation The QMS system requires forced air cooling to operate at a reasonable temperature. Do not block the air inlet or exhaust on the back of the unit. Components will fail without this cooling. Lifting The QMS system is heavy; use care when lifting.
v SRS QMS Gas Analyzer
vi Fast Start • Connect the power cord to the QMS. Set the four switches on the control panel to off and turn on the main power switch. • Turn on the diaphragm pump switch and the turbo pump switch. The pumps should begin the startup sequence, which takes several minutes. When both green lights on the display are bright the system is ready to operate. • Connect the serial cable between the RGA and an available COM port on the computer (typically COM2).
vii Specifications Inlet Type capillary: available in stainless steel, PEEK, and glass lined plastic Flowrate 1 to 10 milliliter per minute at atmospheric pressure Response time <400 ms Pressure selectable from 10 mbar to 1 bar Mass Spectrometer Type quadrupole Detector Faraday cup standard electron multiplier optional Range 1 to 200 atomic mass units (amu) Resolution <0.
viii protection class IP44 Materials (see full materials list for details) construction: SS304 and SS316 insulators: alumina, ceramic seals: Viton, buna-N, and nitrile butyl rubber misc: aluminum, Tygon General Startup time 2 minutes from full stop Max. Ambient Operating Temperature 35 °C Power requirement either 110 V / 60 Hz or 220 V / 50 Hz (not field selectable) less than 600 W total Dimensions 44 cm H × 20 cm W × 61 cm D ( 17 in H × 8 in W × 24 in D ) Weight 34 kg (75 lb.
ix Materials List SRS receives many requests for information about corrosion compatibility. It is our policy not to state the compatibility of our system with various corrosive environments. We simply cannot test the myriad combinations of environments that our customers use. We do provide a list of all the materials exposed to the gas being introduced into the system.
x Calibration Log SRS serial number ___________ In the table below are the results of the factory calibration of the inlet and capillary. The factor is entered in the pressure reduction factor dialog box (under the Utilities menu) in the RGA software. Although the RGA software will store the value for you, a written record is recommended.
Chapter 1. Introduction & Operation In This Chapter Introduction ......................................................................................................................................................................1–2 External Connections ................................................................................................................................................1–3 Operating Orientation .....................................................................................
1–2 Introduction Introduction The QMS 100 series instruments are modern mass spectrometers designed for the analysis of light gases. The three systems, 100, 200 and 300, differ only in the mass range they can detect. A quadrupole mass spectrometer performs the task of analyzing the gas. The spectrometer operates at high vacuum and therefore, pumps are required to draw the gas into the instrument and maintain the vacuum.
Introduction 1–3 needs of most users. For users with specialized needs, the QMS can be controlled from user programs. The Technical Reference Manual discusses details of the QMS, its programming, and service. External Connections The instrument has two gas connections: an inlet on the front panel and an exhaust on the back panel. The inlet connection is a 1/4 inch Ultra-Torr port, which is a high vacuum o-ring seal. The capillary is installed in this port.
1–4 What’s Inside ? The system exhausts to the rear panel. All of the gas drawn into the inlet is exhausted through this port. The port is a 1/4 inch Swagelok tube stub, which can be connected to a wide variety of tube fittings. When sampling hazardous gases, the user must ensure that the exhaust gas is properly handled. The pump behind the exhaust port cannot produce significant pressure above atmospheric; therefore, provide a low resistance path when connecting extra exhaust tubing.
What’s Inside ? 1–5 a length of 0.9 m. Most of the capillary flow does not travel to the RGA, but is bypassed directly to the diaphragm pump. A small part of this flow is drawn through a small aperture (60 µm diameter) into the chamber where the RGA is located. The RGA chamber is maintained at approximately 10-6 mbar by a hybrid turbomolecular/drag pump. The flow through the RGA chamber is recombined with the flow that was bypassed around the chamber.
1–6 What’s Inside ? Mass Spectrometer A residual gas analyzer (RGA) is mass spectrometer of small physical dimensions whose function is to analyze the gases inside the vacuum chamber. The principle of operation is the same for all instruments: A small fraction of the gas molecules are ionized to create positive ions, and the resulting ions are separated, detected and measured according to their molecular masses.
Operation 1–7 • • Histogram scanning Single mass measurement RGA Windows provides fast access to all the RGA functions without the need for any computer programming; however, the instrument can also be programmed directly using the RGA Command Set supported by its serial interface. Consult the RGA Programming chapter of the Technical Reference for information on programming and a complete listing of the RGA Command Set.
1–8 Operation Front Panel Operation The two pumps and two valves are operated with the four switches on the small panel (see Figure 5). The Pressure bar display is the pressure at the inlet port on the instrument front panel. The Current bar display is an indication of the current drawn by the turbo pump and is useful as a system diagnostic. Each square in the display is 0.1 A; typically 2-3 bars will be lit.
Operation 1–9 Controller State Diagram 0 -1 Off Vent 1 R ou gh P um p 2A 2B Tur bo Pum p Te s t B yp as s 2 1 2 3 B yp a ss F low 2 E r r or co n dition s wh ich cau s e a ret reat to previ ou s s tate: 4 5 B at ch An a lyze 1 T u r bo pum p is no t at s pe ed 2 P r es s u r e is h igh S a m p le F low Figure 1-6. Controller state diagram. The gray boxes show which side of the switch is pressed; off is the left.
1–10 Operation The microcontroller is inactive for about 5 seconds after main power is turned on. The user cannot turn on any of the system components during this period. If the user does turn on one of the front panel switches during this period, it will be rejected and the adjacent light will blink. To recover from this state, turn off all four switches and begin again. This restriction is related to power failures, which are discussed later in this chapter.
Operation 1–11 established, the sample valve will open, and measurements can be made. When the capillary flow valve is first opened, a pressure pulse will occur in the system that will invariable shutoff the RGA filament. If you where previously making measurements at state 2B, the RGA filament should be turned off while starting the sample flow. Restart the RGA after the sample flow has been established.
1–12 Operation If the diaphragm pump is inadvertently stored under vacuum for extended periods, the internal pressures will reach a state that prevents the pump from starting. If this has happened the user will hear a relay click but the diaphragm pump will not start. This locked state is cured by venting the system; the diaphragm pump will then start up. Storage under vacuum also temporarily degrades the ultimate pressure of the diaphragm pump.
Operation 1–13 Microcontroller Error Checks The microcontroller is programmed to prevent the system from restarting after a power failure. If the Mechanical Pump switch is turned on before line power is applied, the controller will halt and prevent further action from taking place. It will stay halted until the Mechanical Pump switch is turned off, which resets the system. When the system is halted after a power failure, you will see that the diaphragm pump switch is on and the light is flashing.
1–14 Operation Operating Modes of the Spectrometer The RGA is a mass spectrometer that analyzes residual gases by ionizing some of the gas molecules (positive ions), separating the resulting ions according to their respective masses and measuring the ion currents at each mass. Partial pressure measurements are determined with the help of previously calculated sensitivity (i.e. calibration) factors by reference to the abundance of the individual mass numbers attributed to each gas type.
Operation 1–15 RGA Windows uses the two modes to generate the data for the Analog and Histogram Scan Modes. Analog scanning is the most basic operation of the RGA as a quadrupole mass spectrometer. During analog scanning the quadrupole mass spectrometer is stepped at fixed mass increments through a prespecified mass-range. The ion current is measured after each mass-increment step and transmitted to the host computer over RS232.
1–16 Mass Spectrometry Basics Mass Spectrometry Basics The RGA can perform both qualitative and quantitative analysis of the gases in a vacuum system. Obtaining spectra with the RGA is very simple. Interpreting the spectra, that is, understanding what the spectra is trying to tell you about your vacuum system requires some work. The following sections will introduce some basic concepts of Spectral Analysis emphasizing the main aspects of Residual Gas Analysis.
Mass Spectrometry Basics 1–17 Notes on Fragmentation Patterns : The electron impact type of ionizer used in modern RGA’s almost always causes more than one kind of ion to be produced from a single type of gas molecule. Multiple ionization, molecular fragmentation and changes in the isotopic composition of the molecule are responsible for the effect. All ions formed contribute to the mass spectrum of the molecule and define its fragmentation pattern.
1–18 Mass Spectrometry Basics Sg = RGA’s partial pressure sensitivity factor for gas g, in amp/Torr (see Partial Pressure Sensitivity Factor below) Pg = Partial pressure of gas g in the system. Equations (1) and (2) are combined to obtain the system of equations: HM = Σ g (Sg α Mg ) Pg (3) Since all gases have more than one peak in their fragmentation pattern, the number of peaks (M) in a real spectrum is generally larger than the number of gases (g).
Mass Spectrometry Basics 1–19 The sensitivity of the RGA varies with different gases, changes with time due to aging of the head, and is a strong function of the operating conditions of the instrument. Careful quantitative analysis requires that the sensitivity factor, Sg , be determined for every gas which may be a component gas in the system being analyzed.
1–20 Mass Spectrometry Basics built into the program, can adjust the CDEM voltage for any gain between 10 and 106. Consult the RGA On-Line Help Files for details on the automated tuning procedures built into the RGA Windows program. Also see the Sensitivity and Electron Multiplier Tuning sections of the RGA Tuning Chapter for more general information.
Chapter 2. Windows Software The QMS system contains a mass spectrometer that belongs to a class of spectrometers commonly referred to as residual gas analyzers or RGA. RGAs are low resolution, low mass range, quadrupole spectrometers. The SRS spectrometer is used both as a stand-alone RGA and in the PPR and QMS systems. The same software package is used to operate all three instruments. The description in this chapter refers to the spectrometer as RGA.
2-2 Overview Running in Split Display Mode...............................................................................................................2-16 Manual Scaling of Graphs.......................................................................................................................2-16 Using Scan Data as Background .............................................................................................................2-16 General Utilities............................................
Overview 2-3 Overview Program Structure The RGA program is a fully interactive Windows program capable of managing several RGA Heads simultaneously. Fully interactive means that you can double-click on any graph object and the program responds by executing a specific command such as editing the color of a data line. RGA was designed to handle data acquisition from multiple heads simultaneously by assigning one head for each window and by making all the windows independent from each other.
2-4 System Requirements RGA ASCII Data files (.txt) The RGA program can save the last scan data in an ASCII format that is easily read by spreadsheet programs for data analysis. The file header contains the scan setup information followed by the scan data. The RGA program does not read these ASCII file, it only writes them. RGA Graph Metafiles (.wmf) RGA can also save the active graph as a Windows Metafile. Windows Metafiles are easily read by many word processing, page layout, and graphic programs.
Getting Started 2-5 Starting the RGA Software To start the RGA software simply double-click on the RGA icon in the "SRS RGA" program group created by the RGA installation program. You may also type the full path name of the RGA program in the Run command from the Program manager. The program also accepts a file on the command line. If a filename is specified, the program will open that file at startup. You can open the program by double clicking on any file with the .rga extension. You can open any .
2-6 Features and Operation The recommended shut-down procedure is: 1. Stop the scan if there is one in progress using the Stop Now command in the Scan menu. 2. Turn off the filament and CEM. 3. Save the RGA file you have been working on, using the Save or Save As command in the File menu. 4. Terminate the RGA program using the Exit command in the File menu. 5. Turn off the RGA Head.
Features and Operation 2-7 Analog (Mode Menu) Analog mode is the spectrum analysis mode common to all Residual Gas Analyzers. The XAxis represents the mass range chosen in the Mass Spec Parameters menu. The Y-Axis represents the ion current amplitudes of every mass increment measured. Select the Schedule menu to set the scan trigger timing. Once the scan is in progress, the AutoScale menu may be used to scale the data.
2-8 Features and Operation Spec Scan Parameters menu button on the toolbar Table entries can be configured independently from each other. Some entries can use the Channel Electron Multiplier (CEM), while others can have different scan speeds with the CEM off.
Features and Operation 2-9 parameters, alarm parameters, and graph trace colors. The data acquisition method for the P vs. T scan will vary depending on the display mode selected: In P vs. T mode or Table mode split with P vs. T mode, each table entry value (partial pressure) is acquired directly from the RGA head by individually querying the partial pressure for the appropriate mass. This is done for all the selected masses using the present scan schedule as a trigger. In P vs.
2-10 Features and Operation The Annunciator channels can be independently configured. Some channels can use the Channel Electron Multiplier (CEM) while others can have different scan speed with the CEM off. The alarm control and level settings can be edited by either double clicking on the Alarm text of the desired Annunciator entry, or by clicking on the 'Alarm X' (where X is the channel number) button for the Annunciator channel in the Table Parameters dialog box.
Features and Operation 2-11 2. Establish a connection between the RGA program and the Head (Connector List Setup in the Head menu, or Connector List button on the toolbar). 3. Select the desired display mode (Mode Menu). 4. Turn On the Filament (Head menu or Filament button). 5. Select the desired scan parameters (Scan menu). 6. Select the desired trigger rate (Scan menu). 7. Select the Start scan command (Scan menu or Start button).
2-12 Features and Operation example, if the background mode in Analog mode is changed to yellow, the background mode of all the other modes remains unchanged. Also, any new file using the Analog mode still uses the default background color. After an RGA file has been edited to have a desired look, it may be used as a template for new files by clearing its data using the Clear Graph Data command, saving it using the Save As command, and opening it again using the Open command.
RGA Head and Scan Parameters 2-13 Background Data This mode is helpful in providing the user with a clean baseline after the background data gets subtracted from newly acquired scans. This utility is available in Analog mode, Histogram mode, Table mode, and P vs. T mode. In Analog mode and Histogram mode the scan must be allowed to finish at the Stop mass before the data can be used as background. Use the Stop at End command from the Scan menu (if in continuous scan mode) to guarantee this condition.
2-14 RGA Head and Scan Parameters Note: Changing scan parameters will result in loss of all displayed data on the screen. Use the File menu to save the data in one of the formats available before changing any scan parameters. Changing Head Parameters The head parameters menu items are available only when there is an SRS RGA Head connected and turned on. The head parameters are variables that depend on the actual RGA Head and reside in non-volatile memory in the RGA Head circuitry.
Display Modes 2-15 Scanning With The Filament Off The software can run experiments with the filament off. This is useful only to researchers who perform experiments that generate their own source of ions. The program will warn you if you start a scan without the filament turned on. This is done to prevent casual use and accidents.
2-16 Display Modes Changing Display Modes A display mode presents the user with a specific way to analyze the RGA data acquired. The RGA program has several display modes including a combination of those modes (split modes). To change the present display mode to any other mode do the following: 1. Stop the scan if one is in progress. 2. Select the desired display from the Mode menu or click on one of the mode buttons in the Toolbar.
General Utilities 2-17 To Enable the Background mode make sure the graph has valid data and the RGA head is connected. In Analog and Histogram mode the scan must be allowed to finish at the Stop mass before the data can be used as background. Use the Stop at End command (if in continuous scan mode) to guarantee this condition. To Enable the Background: 1. If a scan is in progress, issue the Stop at End command from the Scan menu. 2. Select the Background Setup command from the Utilities menu. 3.
2-18 General Utilities In PvsT mode, the cursor values are displayed in the legend box. If the legend view is toggled off you cannot see the cursor values. This off-option can be useful if the legend box obscures some data points. You may move the cursor by either clicking on or near a data point of interest, or by clicking and dragging with the mouse with the left mouse button held down. You also can move the cursor incrementally by using the LEFT or RIGHT arrow keys.
General Utilities 2-19 3. Use the Next Item or Previous Item from the View menu to view the sequential logs (The time and date of the scan appears on each log). Browsing Through the Gas Library Library Browsing Description There are several ways to browse through the gas library depending on the display mode and whether the Library Search utility is active. The Library display mode and search utility are linked together to provide an intuitive interface to locate and view any gas in the library file.
2-20 Head Calibration and Security Analysis Procedure Make sure the RGA window is in either Analog mode or Histogram mode and connected to an RGA head. Set the scan range to be from 1 amu to at least 50 amu. 1. Select the Analyze command from the Utilities menu to bring up the Spectrum Analysis dialog box. You may place the dialog box anywhere on the screen. 2. Press the Setup button if you need to change the gas selection or the analysis units. 3.
Head Calibration and Security 2-21 Please refer to the RGA Tuning Chapter for more information about tuning and calibration. While performing the tuning procedure the total pressure in the vacuum chamber should be around 10E-6 Torr. In order to set the sensitivity factors of the RGA Head you must have a reference pressure gauge installed on your vacuum system. There are two sensitivity factors, one for total pressure and one for partial pressure.
2-22 Head Calibration and Security Peak Tuning the RGA Head WARNING! The peak tuning procedure should be performed by qualified personnel only. A mistuned RGA Head could give erroneous readings. Please refer to the RGA Tuning chapter of this manual for more information about tuning and calibration. All the variables displayed are initially read from the SRS RGA Head when the dialog box is activated.
RGA On-line Help • Press Undo ALL to revert to the initial settings, or • Press Factory Settings to recall factory set values. 2-23 Securing the RGA Head Use this feature in an environment where you would like to restrict access to the head parameters. When the RGA Head is locked, you cannot perform certain parameter editing procedures such as Peak Tuning, Sensitivity Tuning, and Ionizer parameter editing. The encrypted password is stored in the rga.ini file in the Windows directory.
2-24 RGA On-line Help To see the entries for a topic, click the first letter of the word you want to look up, or press TAB to select the letter and then press ENTER. Click on any entry highlighted in green and the topic for that entry is displayed automatically. Commonly Asked Questions A Q&A help files has been included with the RGA program. This file includes the most commonly asked questions about the SRS RGA system. Double click on the RGA Q&A Help Icon to view this file.
Chapter 3. Measurement Techniques This chapter discusses procedures to help the user make accurate measurements with the QMS. Several sections are devoted calibration and tuning procedures. The last sections discuss specific measurement techniques. In This Chapter Calibration ..........................................................................................................................................................................3-2 Effect of Total Pressure ....................................
3-2 Calibration Calibration The QMS has been calibrated at the factory to measure the partial pressure of nitrogen correctly. For many purposes this will be suitable. Overtime the calibration can change or operating conditions may change. There are many factors involved in calibrating the QMS and interpreting the mass spectra. To make accurate measurements, the following conditions need to be met: • The total pressure needs to be known. The main sensitivity factor needs to be calibrated.
Calibration 3-3 Effect of Total Pressure Increasing the total pressure at the inlet of the capillary will increase the flow through the capillary. The higher flowrate in turn will increase the pressure at the RGA. This effect is not linear and in applications where the inlet pressure varies, the user needs to understand the flow at the inlet.
3-4 Calibration range of the QMS with respect to increasing the inlet pressure above the design point. The instrument has little “head-room” and the capillary should be designed for the maximum expected pressure. Below the design point, the QMS can tolerate large decreases in the inlet pressure. The ultimate vacuum of the diaphragm pump limits the lowest pressure at the outlet of the capillary, typically to 0.5 mbar. This pressure is the only operating limit; below it gas would flow out of the QMS.
Calibration 3-5 Calibration of Partial Pressure All quantitative calculations performed with the RGA rely on the assumption that there is a linear relation between the partial pressure and the corresponding RGA signals of the gases. Each gas ionizes differently, and its ions make it through the mass filter with different efficiencies. As a result the proportionality constant relating the ion current of a gas to its partial pressure is dependent on the specific gas.
3-6 Calibration control the filter (electron energy, focus voltage, ionizer current, and ion energy). In the equation above, the two factors are unknown. During calibration only the standard partial pressure and measured ion current are known. Therefore, both factors cannot be determined; only the overall factor can be determined. Both factors can be determined if a second reference pressure gauge is introduced into the RGA chamber.
Calibration 3-7 This completes the calibration. All modes of the software will now report partial pressure at the inlet to the capillary. Be sure to record these values as they can be used to diagnose system performance. The pressure reduction factor is saved in the .RGA file; make sure to select File|Save to record the new pressure reduction factor. Basic Recalibration Some situations will require recalibration of the instrument.
3-8 Calibration Calibration for Multiple Operating Conditions The QMS capable of being used over a variety of operating conditions, which in turn require different overall sensitivity factors. Examples are: • • • one QMS system used with multiple capillaries measurements of gas streams at different total pressure, temperature, or composition measurements at multiple ionizer conditions The RGA sensitivity factor is not meant to be directly adjusted by the user.
Calibration 3-9 The Peak Tuning procedures described in this section allow the user to calibrate the mass scale and the resolution, ∆m10%, of the mass spectrometer. The RGA has a very solid design and this type of tuning procedures should rarely be needed. WARNINGS The peak tuning procedures should be performed by qualified personnel only. A mistuned RGA Head will give Erroneous Readings until it is retuned properly.
3-10 Calibration General Procedure Peak tuning is a simple procedure that requires the introduction of two known gases into the vacuum system. A low mass gas (1-20 amu recommended) is used to adjust the low end of the mass axis, a high mass gas, with a mass-to-charge ratio close to the upper limit of the instrument’s mass range, is used to adjust the high end of the mass scale. Several analog scans are performed on the sample and the peak positions and widths are checked and adjusted as necessary.
Calibration 3-11 Low Mass High Mass 1 Ar ++ 0.9 0.8 0.5 0.8 0.7 0.7 0.6 0.9 0.6 + H2 0 0.5 0.4 0.4 86 Kr+ 0.3 0.3 0.2 0.2 0.1 0.1 0 0 15 16 17 18 19 20 21 22 23 24 25 80 81 82 83 84 85 86 87 88 89 90 amu/e amu/e Users writing their own computer code can write Peak Tuning Commands for their own programs using the Tuning Commands of the RGA Command Set and the instructions of the following two sections.
3-12 Calibration scale. An increase in RI causes the low end of the analog spectrum to displace towards lower masses (A small effect is seen at the high masses). An increase in RS results in the spacing between peaks in a scan to decrease (with the largest effect seen at the high mass end).
Calibration 3-13 (Slope), stored in the non-volatile memory of the RGA, to calculate the 8 bit settings of the DAC according to the linear equation: DAC8 (m) = DS . m + DI (DC_Tweek (m) = (DAC8(m) - 128) . 19.6 mV) where m is the mass in amu, and DAC8(m) is the 8 bit setting at that mass. The purpose of the Peak Width Tuning Procedure is to determine the values of DI and DS so that all the peaks in an analog spectrum have the desired peak width (typically Dm10%=1 amu).
3-14 Calibration • The effect is more significant at the higher masses and that is why we do this adjustment second after the width has already been modified by the change in DI. • If the mass-to-charge ratio of the low mass gas is real low this adjustment will have a small effect on the width of its peak. Iterations: In most cases it will be necessary to repeat the two width adjustments one or two more times until both low and high mass peaks show the desired widths.
Calibration 3-15 Electron Multiplier Tuning Procedure Accurate quantitative measurements with the electron multiplier detector require the determination of the CDEM gain for all the ion peaks being measured. Frequent recalibrations are recommended to correct against aging of the device. The gain of the electron multiplier (CDEM) in the RGA is defined relative to the Faraday Cup output (which is assumed to be mass independent).
3-16 Techniques Techniques Correcting for the Chamber Background Even with the sample flow and capillary flow valves closed, their will be a noticeable background in the mass spectrum. This background in the analyzer chamber is caused by outgassing from the chamber surfaces, backstreaming through the turbomolecular pump, and gas production from the ionizer of the RGA. These three processes account for the ever present background of hydrogen, water, nitrogen, oxygen, and carbon dioxide seen in high vacuum.
Techniques 3-17 Correcting for Multiple Species As discussed above, the QMS is calibrated at one mass number. Because every gas behaves differently, analog scans can only show peak heights that are correct at the one mass number. It is not possible to correct the analog and histograms at every mass number. The RGA would have to know what species was causing the ion current at each mass.
3-18 Techniques When the gas being measured is significantly hotter than the QMS system, condensation is likely and presents a problem. If the species at the inlet are gases only at temperatures above room temperature, they can condense when they reach the QMS. The condensed material will continually build up in the QMS and cover the valve seats and aperture. Two approaches can prevent this problem: control the location of condensation or prevent condensation.
Glossary The following is a listing of some of the most important terms used throughout the SRS RGA Operations Manual. For a more complete listing of terms relevant to partial pressure analyzers in general, refer to: “A Dictionary of Vacuum Terms used in Vacuum Science and Technology, Surface Science, Thin Film Technology and Vacuum Metalurgy”, edited by M. S. Kaminsky and J. M. Lafferty, published by the American Vacuum Society, 1979. A. Basford et. al., J. Vac. Sci. Technol.
Glossary Electron Energy. The kinetic energy of the electrons (in eV) used for electron bombardment in the ionizer. Note: In the SRS RGA the Electron Energy is equal to the voltage difference (in Volts) between the filament and the anode grid. Electronics Control Unit (abbreviation: ECU). Electronics box that attaches directly to the probes feedthrough flange and contains all the necessary components to operate the quadrupole mass spectrometer and communicate with a host computer. Faraday Cup.
Glossary Ionization efficiency. The ionization probability normalized to the probability of ionization of a reference gas. Ionization Potential. The minimum energy per unit charge (often in eV) required to remove an electron from an atom (or molecule) to infinite distance. Note: In the SRS RGA the Electron energy must be set above the ionization potential of the molecules for ionization to occur. Ionization probability.
Glossary cannot be differentiated from each other with most mass spectrometers. Note: Mass spectrometers do not actually measure the molecular mass directly, but rather the mass-to-charge ratio of the ions. For singly charged ions, the mass to charge ratio is numerically equal to the mass of the ion in atomic mass units (amu). Minimum Detectable Partial Pressure change (MDPP). The partial pressure change corresponding to the smallest signal change which can be distinguished from noise.
Glossary Response time - is a measure of the steepness of the response when a step change is presented at the inlet. RGA - residual gas analyzer (a class of QMS) RGA Cover Nipple. CF Nipple that covers the RGA Probe. Scan Speed (mass spectrometer). The speed at which the RGA scans through a range of successive mass numbers. Scanning. The procedure of continuously changing the mass tuning of the quadrupole mass spectrometer to bring successive mass numbers into tune. Sensitivity calibration.
References General RGA information Dawson, “Quadrupole Mass Spectrometery and Its Applications”, AIP Press, NY, 1995. Drinkwine and D. Lichtman, “Partial Pressure Analyzers and Analysis”, AVS Monograph Series published by the Education Committee of the American Vacuum Society Basford et. al., J. Vac. Sci. Technol., A 11(3) (1993) A22-40: “Recommended Practice for the Calibration of Mass Spectrometers for Partial Pressure Analysis. Update to AVS Standard 2.3”.
Glossary SRS QMS Gas Analyzer
Technical Reference Manual QMS 100 Series Gas Analyzer Version 3.
Certification Stanford Research Systems certifies that this product met its published specifications at the time of shipment. Warranty This Stanford Research Systems product is warranted against defects in materials and workmanship for a period of one (1) year from the date of shipment. Service For warranty service or repair, this product must be returned to a Stanford Research Systems authorized service facility. Some components may be serviceable directly from the supplier.
Table of Contents Safety.................................................................................................................................................................................................iv Specifications ....................................................................................................................................................................................v Materials List.................................................................................
iv Safety Line Voltage The QMS system is specified for power line of either 110 V / 60 Hz or 220 V / 50 Hz. The diaphragm pump will only operate on the specified voltage. Operating at other voltages will damage the motor. For 110 V operation use one 3 A fuse. For 220 V operation, two 1.5 A fuses must be used in the power entry module. Exhaust As shipped, the QMS system exhausts to the atmosphere.
v Specifications Inlet Type capillary: available in stainless steel, PEEK, and glass lined plastic Flowrate 1 to 10 milliliter per minute at atmospheric pressure Response time <400 ms Pressure selectable from 10 mbar to 1 bar Mass Spectrometer Operational: Mass filter type Quadrupole (Rod diameter: 0.25”, rod length: 4.5”) Detector type Faraday cup (FC) - standard Electron multiplier (CDEM) - optional Resolution Greater than 0.5 amu @ 10% peak height (per AVS standard 2.3).
vi Recommended bakeout temperature 100 - 250 C Ionizer: Design Open ion source. Cylindrical symmetry Operation Electron impact ionization. Material SS304 construction Filament Thoriated Iridium (dual) with firmware protection. Field replaceable. Degas 1 to 10 W Degas ramp-up. Electron energy 25 to 105 V, programmable. Ion energy 8 or 12 V, programmable. Focus voltage 0 to 150 V, programmable. Electron emission current 0 to 3.5 mA, programmable.
vii Technical Reference
viii Materials List SRS receives many requests for information about corrosion compatibility. It is our policy not to state the compatibility of our system with various corrosive environments. We simply cannot test the myriad combinations of environments that our customers use. We do provide a list of all the materials exposed to the gas being introduced into the system.
ix Command List Initialization Name Description Parameters Echo ID Identification Query ? ID String IN Initialization 0,1,2 STATUS Byte Ionizer Control Name Description Parameters Echo DG Degas Ionizer 0-20, * STATUS Byte EE Electron Energy 25-105, *, ? STATUS Byte or query response FL Electron Emission Current 0-3.
x HS Histogram Scan Trigger 0-255, *, none Ion Currents MF Final Mass 1-M_MAX, *, ? Query response MI Initial Mass 1-M_MAX, *, ? Query response MR Single mass measurement 0, M_MAX Ion Current SA Steps per amu 10-25,*,? Query response SC Analog Scan Trigger 0-255,*, none Ion Currents TP Total Pressure measurement 0, 1, ? Ion Current Parameter Storage Name Description Parameters Echo MG CDEM gain storage 0.0000-2000.
xi Error Reporting Name Description Parameters Echo ER STATUS Byte Query ? Query response EP PS_ERR Byte Query ? Query response ED DET_ERR Byte Query ? Query response EQ QMF_ERR Byte Query ? Query response EM CEM_ERR Byte Query ? Query response EF FIL_ERR Byte Query ? Query response EC RS232_ERR Byte Query ? Query response Note: M_MAX= 100 for RGA100, 200 for RGA200 and 300 for RGA300.
Chapter 1. Principles of Operation The QMS consists of two main subsystems: the gas handling inlet and the mass spectrometer. These two subsystems operate independently of each other. The gas handling subsystem delivers the sample to the spectrometer chamber. It has no control of the spectrometer or communications with it. The spectrometer only analyzes the sample. It has no knowledge of the pressure reduction or the gas handling subsystem.
1-2 Internal View Internal View Figure 1. Main components of the QMS are labeled: 1. microcontroller 2. aperture 3. sample valve 4. pressure gauge 5. bypass valve 6. quadrupole electronics 7. mass spectrometer 8. analyzer chamber 9. 24V power supply 10. turbo pump controller 11. diaphragm pump 12.
Overall System 1-3 Overall System The QMS was designed to be a self contained instrument. Only line power is required to operate the instrument. One serial cable between the instrument and a computer is required to run the software. No ancillary gas supplies are necessary. Power Internally the QMS uses line power (110 or 220) and 24 VDC. The line power is distributed to the 24 V power supply and a relay connected to the diaphragm pump.
1-4 Overall System The pressure gauge operates on 15 VDC, which is provided by the microcontroller. The gauge has onboard electronics that provide a setpoint comparison. The setpoint check is used by the microcontroller to determine if the system is operating acceptably. The gauge also outputs an analog signal related to the pressure. This signal is displayed on the front panel. The output of the gauge is not linear, and thereby the spacing of the numbers on the display is irregular.
Pressure Reducing Inlet 1-5 Pressure Reducing Inlet The gas handling subsystem is designed to achieve several goals: • reduce the pressure of the sample gas to the operating range of the mass spectrometer (<10-5 mbar) • provide a quick response time to changes of sample composition at the inlet • allow for easy connection to system being measured • use conventional materials If only the first goal where important a single stage pressure reduction would be suitable.
1-6 Pressure Reducing Inlet Flow Calculations The pressure and flowrates of the sampled gas can be calculated with simple formulas. The calculations here assume that gases behave ideally, which is a reasonable approximation at the temperatures and pressures involved. Actual system performance compares well with these simple calculations.
Pressure Reducing Inlet 1-7 where Cbd is the conductivity of the tube from the tee to the diaphragm pump. The flow through the aperture is: Qsample = Cap ( Pb − Pc ) ≅ Cap Pb , (4) where again the large pressure drop allows the approximation to be used. The turbo pump is an active component that is characterized by Pc = Qsample S , (5) where S is the speed of the pump and has the same units as conductivity (liter s-1 ).
1-8 Pressure Reducing Inlet These last two characteristics greatly simplify the selection of alternate capillaries and is discussed later in this chapter. Diaphragm Pump 3 2.5 speed (liters/min) A measured speed curve for the diaphragm pump is shown in the figure at the right. The speed is the volumetric flowrate at that pressure. Because mechanical pumps have much lower flowrates than turbo pumps, the speed is usually expressed in volume per minute.
Pressure Reducing Inlet 1-9 Turbo Pump speed The pump attached to the spectrometer chamber is hybrid turbomolecular/drag pump. The turbo pump hybrid design of this pump allows it to diaphragm pump exhaust at high pressure (relative to conventional turbomolecular pumps). The pumping speed is constant at the nominal value of 70 l s-1 over a large range of exhaust pressures. As the exhaust pressure approaches the maximum value, the speed begins to drop.
1-10 Capillary Design Capillary Design The inlet uses a bypass configuration that results in a fast response time. A large flow is drawn through the capillary tube, which drops the pressure 3 decades. The typical capillary used at atmospheric pressure has a bore diameter of 0.125 mm and a length of 0.7 m. Any number of combinations of length and bore diameter can achieve the same flowrate and pressure drop. Capillaries are available in several materials.
Capillary Design 1-11 The chromatography industry uses a large variety of capillaries, from which we can select capillaries for the QMS. The figure below shows the conductivity for several commonly available bore diameters. 1E-02 1E-03 C (liter/s) 1E-04 4 5 6 7 1E-05 2 1E-06 1E-07 1E-08 1 10 100 1000 length (cm) Figure 6. Conductivity of five different capillaries as a function of length. The curves are labeled with the bore diameter in thousandths of an inch. Both axis are logarithmic.
1-12 Capillary Design Materials and Fittings Users will find vendors of gas chromatography supplies a good source for capillaries and fittings. Capillaries are available in many materials. No material is ideal for all applications. The following table list features of several materials material min. bore diameter advantages disadvantages stainless steel 0.005 in · rugged · difficult to cut without clogging the bore · high temperature · durable connections PEEK 0.
Capillary Design 1-13 Extensions As discussed in the previous section, the capillary can be designed to any length necessary by choosing an appropriate bore diameter. The cost of material might warrant the use of an extension of another material, e.g. common vinyl tubing. This can be accomplished as long as the extension is added to the vacuum side of the capillary: CORRECT 3 mm ID x 4m L capillary INLET QMS INCORRECT Figure 7.
Chapter 2. Quadrupole Spectrometer This chapter describes the design and principles of operation of the components of the RGA quadrupole probe. In This Chapter Introduction .......................................................................................................................................................................2-2 ECU....................................................................................................................................................................
2-2 Introduction Introduction The SRS RGA is a mass spectrometer consisting of a quadrupole probe, and an Electronics Control Unit (ECU) which mounts directly on the probe’s flange and contains all the necessary electronics for operating the instrument. Figure 1 Quadrupole Head Components The probe is a specially engineered form of quadrupole mass spectrometer sensor. It is mostly constructed out of type 304 stainless steel and high purity alumina.
ECU 2-3 ECU Independently from the gas handling susbsystem, the ECU completely controls the operation of the spectrometer, handles its data and transmits it to the computer for analysis and display. The ECU is a densely packed box of electronics (3”x4”x9”) that connects directly to the probe’s feedthru-flange and also to a host computer. It includes several regulated power supplies, a built-in microprocessor, control firmware, and a standard RS232 communications port.
2-4 ECU changes in the calibration parameters by inexperienced operators. Peak tuning is completely disabled when the jumper is configured to the CAL DIS setting.
Electrometer 2-5 Electrometer Detection limit vs. scan rate A unique, temperature-compensated, logarithmic picoammeter built into the ECU box measures the ion currents collected by the Faraday cup (FC), or electron multiplier (CDEM). The output voltage of the electrometer is equal to the logarithm of the ion current so that several decades of signal can be read on the meter without any gain switching being necessary.
2-6 Electrometer When using the RGA Windows program to operate the RGA, the Scan Speed parameter setting available in the Scan Parameter Setups of the Scan menu is used to set the NF parameter value in the RGA Head according to the equation: NF = ScanSpeed - 1. The following table summarizes the performance of the RGA electrometer during mass measurements as a function of the Scan Speed and NF settings.
Mass Filter Power Supply 2-7 Mass Filter Power Supply All the necessary electronics required to power up the quadrupole mass filter during mass measurements are built into the ECU box. The RF/DC levels for each mass are set and regulated from the ECU, under microprocessor control, and based on internal calibration parameters permanently stored in non-volatile memory. The difference between the three spectrometer models (100, 200 and 300) is given by the maximum supply voltage available to the rods.
2-8 Ionizer Ionizer Positive ions are produced in the ionizer by bombarding gas molecules with electrons derived from a heated filament. The ions are then directed toward the entrance of the ion filter where they are separated based on their mass-to-charge ratio. Description The SRS RGA ionizer is of an open design (wire mesh construction) with cylindrical symmetry and mounted co-axially with the filter assembly.
Ionizer 2-9 Principle of operation The principle of operation of the ionizer is similar to the Bayard-Alpert gauge, except there is no central wire collector, and the electron repeller has been added. Figure 4 Ionizer Schematic The filament is the source of the electrons used in ionizing the gas molecules. It operates at a negative potential relative to ground and is resistively heated to incandescence with an electrical current from the emission regulator.
2-10 Ionizer Parameter Settings The parameters that affect the ionization efficiency of the ionizer are: electron energy, ion energy, electron emission current and focusing voltage. The general principles by which they affect the performance of the source are well understood. The ECU contains all the necessary high voltage and current supplies needed to bias the ionizer’s electrodes and establish an electron emission current.
Ionizer 2-11 Ion energy also determines the time spent by the ions in the fringing fields at the entrance and exit points of the filter. Ions passing through the fringing fields can collect high transverse velocities and are more likely to collide with the quadrupole rods and never be collected at the detector. As a result, ion signals (i.e. sensitivity) generally increase with ion energy. The focus plate negative potential can be adjusted to any value within the range of 0 to -150 V.
2-12 Quadrupole mass filter Quadrupole mass filter Positive ions are transferred from the ionizer into the quadrupole where they are filtered according to their mass-to-charge ratios. Ions that successfully pass through the quadrupole are focused towards the detector by an exit aperture held at ground potential. Description The quadrupole mass filter is an electrodynamic quadrupole operated by a combination of DC and RF voltages.
Quadrupole mass filter 2-13 potential terms. The radius of the circle inscribed by the rods is 0.109”. The frequency of operation is f=2.7648 MHz. Principle of operation The following figure schematically represents the quadrupole mass filter and its connections. Figure 6 Quadrupole Connections During operation, a two dimensional (X-Y) quadrupole field is established between the four cylindrical electrodes with the two opposite rods connected together electrically.
2-14 Quadrupole mass filter compared to other types of analyzers. The upper limit of useful operation is determined by the collisions between the ions and the neutral gas molecules. In order to avoid collisional scattering it is necessary to maximize the mean free path of the ions. The general principle of operation of the filter can be visualized qualitatively in the following terms: One rod pair (X-Z plane) is connected to a positive DC voltage upon which a sinusoidal RF voltage is superimposed.
Quadrupole mass filter 2-15 The mass range is the range of masses defined by the lightest and the heaviest singly charged ions which can be detected by the mass spectrometer. The spectrometer is offered in three different models with mass ranges of 1 to 100, 200, and 300 amu. The main difference between the three models is given by the maximum supply voltage available to the rods.
2-16 Quadrupole mass filter It is well established that the resolution attainable by a quadrupole is limited by the number of cycles of RF field to which the ions are exposed before they reach the detector. In practice, the minimum resolution (∆M10%) value attainable is mass independent, linearly related to the ion energy, and inversely proportional to the square of the product of the quadrupole length and frequency.
Ion Detector 2-17 Ion Detector Positive ions that successfully pass through the quadrupole are focused towards the detector by an exit aperture held at ground potential. The detector measures the ion currents directly (Faraday Cup) or, using an optional electron multiplier detector, measures an electron current proportional to the ion current. Description The following figure describes the detector assembly including the electron multiplier option.
2-18 Ion Detector mounting the CDEM cone very close to the top of the FC. The clip anchors the CDEM glass tube to the side of the FC Shield and holds the lower end of the tube at ground. Chrome electrical coatings, deposited at both ends of the tube provide the necessary electrical contacts. A plate (CDEM Anode) mounted at the exit of the CDEM collects the secondary electrons. The resulting electron current flows into the electrometer through a separate feedthru of the flange.
Ion Detector 2-19 of the electron multiplier currents is reversed before the current value is sent out over RS232 so that the computer does not need to do any sign flipping on the currents received when the CDEM is activated. The gain of the electron multiplier in the RGA is a function of the bias voltage and is measured relative to the FC signal. The following figure shows a typical “gain characteristic” (i.e. gain vs bias voltage) curve obtained for H2O+ ions at 18 amu.
2-20 Ion Detector along the channel walls replenishing their charge as secondary electrons are emitted. Channel electron multipliers, operate linearly in the analog mode until the output current is approximately 10% of the bias current. The dark current of a multiplier is the electron current measured at its output in the absence of an input ion current. The minimum output current that can be accurately measured with the multiplier is equal to the dark current noise.
Ion Detector 2-21 applications. However, in order to achieve maximum useful lifetime and optimum performance, it is very important to handle them very carefully. Please read the CDEM Handling and Care section in the Service chapter to familiarize yourself with some of the basic procedures that must be followed for the correct operation of the multipliers.
Chapter 3. Programming the RGA This chapter describes how to program the RGA ECU from a host computer using the RGA Command Set and an RS232 Link. In This Chapter Introduction .......................................................................................................................................................................3-3 The RGA COM Utility ................................................................................................................................................
3-2 Introduction MIparam, param: 1 - M_MAX, *, ? ................................................................................................................3-44 MRparam, param:0 - M_MAX........................................................................................................................3-44 SAparam, param: 10 - 25, *, ?...........................................................................................................................3-46 SC[param], param: 0 - 255, *............
Introduction 3-3 Introduction The RGA comes standard with an RS232 communications port. A host computer interfaced to the RGA can easily configure, calibrate, diagnose and operate the quadrupole mass spectrometer using ASCII commands. The RGA ECU executes the commands in the order received and, when information is requested, data is quickly returned to the computer for analysis and display.
3-4 The RGA COM Utility The RGA COM Utility The RGA Com Utility is a simple Windows™ OS communication program that allows you to communicate with the RGA ECU directly by typing valid RGA commands on your keyboard. The program functions like any common terminal program where the typed characters are sent directly to the serial communications port and any received characters are displayed immediately on the screen. The RS-232 communication parameters of RGA Com are fixed to be compatible with the RGA ECU.
Command Syntax 3-5 Command Syntax The RGA commands are ASCII character strings consisting of a two letter (case insensitive) command name, a parameter, and a carriage return terminator. Note: The carriage return character, decimal ASCII value=13, is represented throughout this manual with the symbol . All command strings must be terminated with this character in order to be acknowledged by the RGA. Valid parameters are: Numbers: Numbers are the most common type of parameter used to program the RGA.
3-6 Command Syntax ID? RGA Identification Query. MI1 Set initial scan mass to 1 amu. MF100 Set final scan mass to 100 amu. FL1.0 Turn on the filament to a 1.0 mA emission current. NF* Use default noise floor setting. (sets scan rate and averaging.) AP? Query the number of scan points to be received by the computer. SC1 Trigger a single analog scan.
Communication Errors 3-7 Communication Errors Communication errors are signaled to the user flashing the Error LED a few times, setting Bit 0 of the STATUS error byte and setting the error-specific bits of the RS232_ERR error byte . Many different circumstances can result in a communication error being reported after a command string is received by the RGA. Some problems are detected early by the command handler and result in the command never being executed.
3-8 Communication Errors Jumper Protection Violation Some calibration related commands are subject to jumper protection. Jumper JP100 on the digital (i.e. top) board of the RGA electronics box can be used to enable/disable some of the tuning features of the instrument. The jumper setting is checked before the command is executed and if calibration is disabled, the Error LED is flashed, Bit 5 of RS232_ERR and Bit 0 of STATUS are set, and the command is not executed.
Programming the RGA ECU 3-9 Programming the RGA ECU This section describes the basic programming steps needed to configure, operate, and diagnose the RGA. The emphasis is on general program implementation without going into specific details on the different commands that are mentioned. Please consult the “RGA Command Set” section of this chapter to get more detailed information on the RGA commands and their implementation.
3-10 Programming the RGA ECU -Check the quality of the serial connection to the host computer. -Check the user’s communication software to make sure it is communicating properly with the RGA. -Check the serial numbers of the RGA ECU’s connected to the computer's serial ports. Programming the Ionizer Positive ions are produced in the ionizer by bombarding residual gas molecules with electrons derived from a heated filament.
Programming the RGA ECU 3-11 Programming the Detector Positive ions that successfully pass through the quadrupole filter are focused towards a detector that measures the ion currents directly (Faraday Cup, FC) or, using an optional electron multiplier (CDEM), measures an ion signal proportional to the ion current. Use the Detection Control commands to choose the detector type (FC or CDEM), query the CDEM option, recalibrate the electrometer’s I-V response and set the electrometer’s averaging and bandwidth.
3-12 Programming the RGA ECU Please consult the RGA Command Set section for details on the CA command. Detector Programming example The following list of commands starts by checking the RGA ECU to make sure there is a multiplier installed: A CDEM is present if a 1 response is sent back to the computer. After the test (and assuming the CDEM option was detected), a voltage of -1400V is set across the multiplier, and the noise floor setting is programmed for minimum averaging and maximum scan rate.
Programming the RGA ECU 3-13 • Follow all recommended procedures for the operation of the CDEM. Consult the RGA Maintenance chapter for complete CDEM Care and Handling information. Setting up Analog Scans Analog scanning is the most basic operation of the RGA as a quadrupole mass spectrometer. During analog scanning the quadrupole mass spectrometer is stepped at fixed mass increments through a prespecified mass-range.
3-14 Programming the RGA ECU MF150 NF7 Final mass = 150 amu. Fastest scan rate selected. SA10 Steps/amu = 10. AP? Analog Points query. The number 1401 is echoed. Add one for total pressure. SC10 Analog Scan trigger: 10 scans are generated and transmitted. Analog Scan Programming Tips • • • • • • It is good programming practice to follow each command that sets a parameter with a query of the parameter setting.
Programming the RGA ECU 3-15 Histogram scans are triggered with the HS command. The scan parameter can be set for single, multiple and continuous scanning operation. The mass range for the scan is set in advance with the commands MI (Initial Mass) and MF (Final Mass). A current value is transmitted for each integer mass value between MI and MF for a total of (MF-MI +1) measurements (See HP command).
3-16 Programming the RGA ECU • • • • Any command sent to the RGA during scanning will immediately halt the scanning action and clear the RGA’s transmit buffer. Remember to also clear the computer’s receive buffer to reset the communications. The new command responsible for stopping the scan will be executed! It is good practice to perform an analog scan before triggering a large set of histograms to assure the correct peak tuning (i.e. correct peak locations and widths) of the quadrupole mass filter.
Programming the RGA ECU 3-17 • • scanning procedure, referred to as Peak-Locking, is designed to measure peak currents for individual masses in a mass spectrum without being affected by drifts in the mass scale calibration. The Miniscan covers a 0.6 amu range centered at the mass requested, and selects the maximum current from 7 individual measurements performed at 0.1 amu mass increments. The detector settings (i.e.
3-18 Programming the RGA ECU • • • • The output of a D/A converter can be linearly related to the readings obtained at a certain mass. • A relay switch can be closed whenever another mass concentration goes above a certain level. • A digital output can be set high when a third mass goes under a minimum acceptable partial pressure value. For best accuracy of results, it is best to perform all consecutive mass measurements in a set with the same type of detector and at the same noise floor (NF) setting.
Programming the RGA ECU 3-19 gauge readings. Expect to see deviations between the two gauges as the composition of a residual gas changes. Total Pressure measurement example The following list of commands is an example of a total pressure measurement setup. The first step sets up the FC as the detector, and automatically sets the TP_Flag = 1. The second step triggers a total pressure measurement in the RGA ECU.
3-20 Programming the RGA ECU MG: CDEM gain at the HV setting stored in MV. See MG command. See the Parameter Storage commands list in the next section for details. Important: • • • The Parameter Storage commands are used by the RGA Windows software to store and retrieve the partial and total pressure sensitivity factors, and the gain and voltage settings of the CDEM calculated and used by the program.
Programming the RGA ECU 3-21 The net result is very stable RF/DC levels that are highly insensitive to the operating conditions of the RGA ECU. Important: The RF/DC stabilization algorithm (Step 2 above) remains active as long as no new commands are detected by the RGA ECU. Once a new command is received, stabilization stops, and the new command is executed. Use the ML0 command to turn off the RF/DC bias when finished performing measurements and before quitting the program controlling the RGA.
3-22 Programming the RGA ECU 3. The Burnt and Leak LED’s indicate specific filament problems and are turned on, in addition to the Error LED, whenever the ionizer’s emission is internally shut down or not established as requested. 4. Error Queries: Queering the Error Bytes with the Error Reporting commands. The “Error Byte Definitions” section of this chapter describes the different error bytes used to store the results of the internal checks.
Programming the RGA ECU 3-23 The Error LED is immediately turned on if any one of the bits 1-7 of STATUS is set. Bit 0 of STATUS reports communications errors and the Error LED is only flashed twice when the bit is set. The STATUS Byte should be queried regularly by the programming software (ER? command.) Commands that involve hardware control (such as Ionizer Control commands) do diagnostic checks on the hardware as they are executed.
3-24 Programming the RGA ECU The RGA is turned on and, after all the internal checks are performed, the green Power LED and the Error LED are turned on. The red LED signals the operator that a problem was detected. A 24V P/S error is not expected since the Power LED is on. The ER? command returns a STATUS byte with bit 4 set, pointing to a quadrupole mass filter problem. The command EQ? is used to read in the QMF_ERR byte.
RGA Command Set 3-25 RGA Command Set This section lists and describes the commands of the RGA’s Command Set. The commands are separated into several lists, based on their functions. They are each identified by a header that describes the command’s syntax (with the acceptable parameter values), the command’s function, and the information returned (echo) to the computer during execution.
3-26 RGA Command Set Initialization Commands ID? Description: Identification query. Echo: ID string. Use to identify the RGA ECU connected to the host computer. The RGA returns the ID string (ASCII format): SRSRGA###VER#.##SN##### The three string parameters, in the exact format shown above, correspond to: 1. Model number (=M_MAX): 100 for RGA100, 200 for RGA200 and 300 for the RGA300. 2. Firmware version ( for example: 0.23). 3. Serial Number of the unit (5 digit format).
RGA Command Set 3-27 Initialize the RGA to a known state. Three different levels of initialization are available. Command excecution times vary depending on the pre-existing ionizer conditions. The end of the command excecution is prompted to the host computer returning the STATUS byte over RS232. Parameters: IN0: Initialize communications and check the ECU hardware. • The input and output data buffers are emptied (all communications are disabled while this happens).
3-28 RGA Command Set Ionizer Control Commands DGparam, param: 0 - 20,* Description: Ionizer Degas command Echo: STATUS error byte (unless command is stopped before completion, or param=0). DEGAS the ionizer by heating and electron stimulated desorption. The parameter represents the desired DEGAS time in minutes and includes a one minute initial ramping time. Warning: Repeated degassing will considerably limit the lifetime of the filament.
RGA Command Set 3-29 8. At the end of the time specified by the parameter (and if no problems were encountered) the Degas_LED is turned off. 9. Ionizer goes back to pre-Degas configuration 10. The electron emission current is reprogrammed to its pre-Degas value and background filament protection is reenabled. 11. The Filament LED is updated. 12. The STATUS byte is sent out to the host computer to indicate the DEGAS process is over.
3-30 RGA Command Set Command excecution times vary depending on the pre-existing ionizer conditions. The end of the command excecution is prompted to the host computer by sending out the STATUS byte over RS232. Note: The Electron Impact Ionization Energy is set to the default value when the unit is turned on. Important: The repeller grid and the focus plate are only biased while the filament is emitting electrons.
RGA Command Set 3-31 • The repeller grid and the focus plate are only biased while the filament is emitting electrons. • In order to protect the filament, the emission current is defaulted to zero when the RGA is turned on. • The CDEM is turned off by any overpressure that also shuts down the filament. Parameters : FL0.00: The filament is turned off and the repeller grid and the focus plate are grounded. FLparam, param: 0.02-3.
3-32 RGA Command Set Since the axis of the quadrupole mass filter is at ground, the ion energy (in eV) is equal to the anode grid voltage (in Volts). Important: The anode grid is always biased regardless of the ionizer’s emission status. Upon reset the grid level is set to the default value. Parameters : IE0 Low ion energy: 8 eV . IE1 High ion energy: 12 eV. IE*: The default Ion Energy parameter value is used to run the command. Default: 1 => high ion energy: 12 eV IE?: Query.
RGA Command Set 3-33 Command excecution times vary depending on the pre-existing ionizer conditions. The end of the command excecution is prompted to the host computer sending out the STATUS byte over RS232. Parameters: VFparam, param: 0-150: The parameter represents the magnitude of the focus plate bias potential in Volts (The actual bias voltage is negative). The STATUS byte is transmitted at the end of command execution. VF*: The default Focus plate biasing Voltage value is used to excecute the command.
3-34 RGA Command Set Detection Control Commands CA Description: Calibrate All. Echo: STATUS Error Byte. Readjust the zero of the ion detector under the present detector settings, and correct the internal scan parameters against small temperature fluctuations to assure that the correct RF voltages (i.e. as specified by the last Peak Tuning procedure) are programmed on the QMF rods as a funtion of mass.
RGA Command Set 3-35 Notes: • This mass axis correction procedure can also be triggered at any time, by itself, using the RS and RI commands with no parameters (See Tuning commands). • The correction procedure is also automatically performed at the beginning of all analog and histogram scans. However, no correction is performed at the beginning of single mass measurements since the extra checking would significantly extend the time it would take the measurement to be completed.
3-36 RGA Command Set • All offset correction factors previously stored in memory are cleared after a complete calibration of the electrometer is performed (see CA command for more information). Parameters: Only one possible command format is allowed CL Error Checking: An attempt to pass any parameter with CL results in a bad-parameter error being reported. HVparam, param: 0 - 2490, *, ? Description: Electron Multiplier High Voltage Bias setting. Echo: STATUS error byte or Query Response.
RGA Command Set 3-37 • It is good practice to readjust the Zero of the ion detector every time the type of detector (FC or CDEM) is changed. This is particularly important if the new detector settings have not been used in a long time or since the unit was turned on or recalibrated with the CL command. See the CA command for details and more recommendations. Parameters : HV0: Use this parameter value to “turn off” the Electron Multiplier and enable Faraday Cup (FC) Detection.
3-38 RGA Command Set Error Checking: The CDEM option (Opt01) must be available in the RGA ECU receiving the command or a badcommand error is reported (see MO command for details). Number parameters must be within the accepted range, and must be integers. No parameter (i. e. HV) is treated as a bad-parameter error. Bit3 of STATUS (transmitted at the end of the command) reports errors in the excecution of the command.
RGA Command Set 3-39 A decrease in the Noise-Floor setting results in cleaner baselines and lower detection limits during scans and measurements, but also means longer measurement and scanning times due to the reduced bandwidth of the electrometer and increased averaging. The NF parameter must be chosen keeping in mind the strong interplay between detection limit and acquisition speed.
3-40 RGA Command Set Scan and Measurement Commands AP? Description: Analog Scan Points Query. Echo: Query Response. Query the total number of ion currents that will be measured and transmitted during an analog scan under the current scan conditions. Important: The query response does not include the extra current (4 bytes) corresponding to the total pressure measurement performed at the end of all analog scans (Please see SC command for details). The number of points (i.e.
RGA Command Set 3-41 Important: The query response does not include the extra current (4 bytes) corresponding to the total pressure measurement performed at the end of all histogram scans. (Please see HS command for details). The number of points (ion currents) retuned over RS232 is calculated based on the MI and MF parameter values. Number of points = MF - MI + 1. Each point transmitted represents an ion current and as such corresponds to 4 bytes being received by the host computer.
3-42 RGA Command Set • The detector’s zero and the internal scan parameters are checked and corrected at the beginning of each scan resulting in a slight delay before the scan actually starts. • A Total Pressure measurement is performed at the end of each scan and transmitted out to the host computer (Please see HP and TP Commands). • The measurements are performed with the detector that is active at the time the scan is triggered. Parameters: HS: Continuous scanning mode.
RGA Command Set 3-43 computer over RS232. As a result of the high acquisition rate of the RGA there might be a delay between the time at which the data is collected and the time at which a complete spectrum is displayed by the host computer. The time lag between data acquisition and display depends on a large number of factors including the scan rate (NF setting) of the RGA, the host computer’s processing speed, and the amount of handshaking activity over the RS232 lines.
3-44 RGA Command Set The mass value set by MF must always be greater than or equal to the initial mass setting of MI or else a parameter-conflict communications error is generated. The absence of a parameter (i.e. MF) is treated as a bad-parameter error. MIparam, param: 1 - M_MAX, *, ? Description: Initial Mass (amu) of mass spectra (Analog and Histogram). Echo: Query Response. Set the Initial Mass value (in amu) for Analog and Histogram scans.
RGA Command Set 3-45 The type of detector and noise-floor settings to be used by the measurement must be selected in advance with the NF and HV commands. The precision and duration of the measurement are totally determined by the NF parameter value. The scan rates and signal-to-noise ratios for the different NF settings of the electrometer are listed in a table in the Electrometer section of the “RGA Electronic Control Unit” chapter.
3-46 RGA Command Set The upper mass limit depends on the RGA model number: M_MAX=100 for RGA100, 200 for RGA200 and 300 for the RGA300. Error Checking: The command does not accept query or default parameters. Programming tips: • Single mass measurements are commonly performed in sets where several different masses are monitored sequencially and in a merry-go-round fashion.
RGA Command Set 3-47 Parameters: SAparam, param: 10-25: The parameter specifies the number of steps-per-amu desired during analog scans. SA*: The number of points per amu value is set to its default value. Default: 10 SA?: Query. Returns the SA parameter value currently in use by the analog scans. Error checking: Number parameters must be integers and within the specified range. The absence of a parameter (i. e. SA) is treated as an error. SC[param], param: 0 - 255, * Description: Analog Scan Trigger.
3-48 RGA Command Set • A Total Pressure measurement is performed at the end of each scan and transmitted out to the host computer (Please see AP and TP Commands). • Unless otherwise specified, the measurements are performed with the detector settings that are present at the time the scan is triggered. Parameters: SC: Continuous scanning mode. The RGA produces a continuous string of analog scans. A new command must be sent to the RGA in order to stop the scanning activity.
RGA Command Set 3-49 received to the time it actually starts. Using the SC1 command and waiting until the whole scan data stream is transmitted back to the host computer will minimize the problems that are associated to this feature. • Perform a complete Peak Tuning procedure on the RGA ECU if the peaks in the spectrum do not appear at their correct mass values (See Peak Tuning section in the RGA Tuning chapter). TP?, TP0, TP1 Description: Total Pressure Measurement . Echo: Measured Ion Current.
3-50 RGA Command Set different from that of the Bayard Alpert gauge readings. Expect to see deviations between the two gauges as the composition of a residual gas changes. Parameters : TP0: TP_Flag is cleared. Total Pressure measurement is disallowed and a null current value is returned as a response to a total Pressure Measurement request (note that this includes the total pressure measurement requests at the end of scans!). TP1: TP_Flag is set. Total pressure measurement is fully enabled.
RGA Command Set 3-51 Parameter Storage Commands MGparam, param: 0.0000 - 2000.0000,? Description: Electron Multiplier Gain Storage. Echo: Query Response. Store a value of electron multiplier (CDEM) Gain, expressed in units of thousands, in the non-volatile memory of the RGA ECU. The command is typically used together with the MV instruction to store calibrated sets of [High Voltage and gain] for the Electron Multiplier.
3-52 RGA Command Set Important: The voltage value is not used internally by the RGA to set the bias voltage of the Electron Multiplier, it is simply stored so it can be read and used by a host computer. As expected, this command is only available in ECU’s with a CDEM option installed (See MO command for details). Parameters: MVparam, param: 0-2490: The parameter, interpreted as a CDEM bias voltage in units of Volts, is stored in the non-volatile memory of the ECU. MV?: CDEM Bias voltage query.
RGA Command Set 3-53 STparam, param:0.0000 - 100.0000, ? Description: Total Pressure Sensitivity Factor storage. Echo: Query Response Store a value of Total Pressure Sensitivity, expressed in units of mA/Torr, in the non-volatile memory of the RGA ECU. Important: The sensitivity factor is not used internally by the RGA to turn ion currents into total pressures, it is simply stored so it can be read and used by any host computer connected to the instrument.
3-54 RGA Command Set Mass Filter Control Commands MLparam, param: 0.0000 - M_MAX Description: Mass Lock Echo: none Activate the quadrupole mass filter (QMF) and center its pass-band at the mass value specified by the parameter. The QMF is parked at the mass requested but no ion current measurements take place. The parameter is a real number and the mass increments are limited to a minimum value of 1/256 amu. The command excecution involves two steps: 1.
RGA Command Set 3-55 Error Reporting Commands EC? Description: RS232_ERR Byte Query Echo: RS232_ERR Byte. Query the value of the RS232_ERR byte. The value of the RS232_ERR byte is sent to the computer in ASCII format and with a terminator. RS232_ERR and bit 0 of STATUS are then cleared to provide a clean error reporting slate. Important: See “Troubleshooting the RGA Communications” in the RGA Programming chapter for more details on the use of this query.
3-56 RGA Command Set ED? Error checking: The only acceptable parameter is a question mark. The absence of a parameter (i. e. ED) is treated as a bad-parameter error. EF? Description: FIL_ERR Byte Query Echo: FIL_ERR Byte. Query the value of FIL_ERR. The FIL_ERR byte value is returned to the computer in ASCII format and with a terminator. FIL_ERR can only be modified by the “Filament Protection Mode” which constantly monitors the filament while it is emitting electrons.
RGA Command Set 3-57 This query command can be used to determine whether the CDEM option is installed in the RGA unit being programmed: A CDEM option is available if Bit 7 of CEM_ERR is cleared when the byte is queried (See also MO command). Parameters: This command is a query, and can only have one parameter format: EM? Error checking: The only acceptable parameter is a question mark. The absence of a parameter (i. e. EM) is treated as a bad-parameter error. EP? Description: PS_ERR Byte Query.
3-58 RGA Command Set results). The QMF_ERR byte value is returned to the computer in ASCII format and with a terminator. No errors are present as long as the byte value is zero. Consult the Error Byte Definitions section of this chapter for detatils on the different error bytes of the RGA. Consult the RGA Troubleshooting chapter of this manual for possible causes and solutions to any problems reported. Always try the query a second time before declaring a hardware problem.
RGA Command Set 3-59 Error checking: The only acceptable parameter is a question mark. The absence of a parameter (i. e. ER) is treated as a bad-parameter error.
3-60 RGA Command Set Tuning Commands CE? Description: Calibration Enable Query. Echo: JP100 setting. Query the Calibration Enable/Disable jumper (JP100) status. An internal jumper (JP100) on the digital (i.e. top) electronics board of the RGA’s ECU box can be configured by the end-user to enable/disable the modification of the peak tuning parameters. The CE query command returns the JP100 setting in ASCII format with a terminator.
RGA Command Set 3-61 non-volatile memory of the RGA, to calculate the 8 bit settings of the DAC according to the linear equation: DAC8 (m) = DS . m + DI where m is the mass in amu, and DAC8(m) is the 8 bit setting at that mass. The purpose of the Peak Width Tuning Procedure is to determine the values of DI and DS so that all the peaks in an analog spectrum have the desired peak width (typically 1 amu).
3-62 RGA Command Set Program the value of DS during the Peak Width Tuning Procedure. The parameter (one of four peak tuning parameters) represents the DS value, in units of bits/amu. Warning: Please read the Peak Tuning Section of the RGA Tuning Chapter before using this command. The RGA ECU adjusts the DC levels of the quadrupole filter during measurements so that constant mass resolution is automatically available throughout the entire mass range of the spectrometer.
RGA Command Set 3-63 RIparam, param: -86.0000 - +86.0000, *, ?, none Description: RF_Driver output @ 0 amu (Peak Position Tuning command). JP100 Jumper protected. Echo: Query Response. Warning: Please read the Peak Tuning Section of the RGA Tuning Chapter before using this command. Program the output of the RF_Driver @ 0 amu during a Peak Posion Tuning Procedure. The parameter (one of four peak tuning parameters) represents the voltage output selected for the RF_Driver @ 0 amu, in mV.
3-64 RGA Command Set Error checking: The absence of a parameter (i. e. RI) is treated as an error in the parameter. This parameter is protected by an internal calibration jumper (JP100) and a Protection-violation error will result if the jumper is in the Calibration Disabled mode (see CE command). RSparam, param: 600.0000 - 1600.0000, *, ?, none Description: RF_Driver output @ 128 amu (Peak Position Tuning command). JP100 Jumper protected. Echo: Query Response.
RGA Command Set 3-65 RS: Uses the current parameter value to recalculate the internal scan parameters used to step the RF during scans and single mass measurements. This is often used to compensate against small temperature drifts in the mass scale, caused by drifts in the output of the RF_Driver. Error checking: The absence of a parameter (i. e. RS) is treated as an error in the parameter.
3-66 Error Byte Definitions Error Byte Definitions The Error Bytes described in this section store the results of the firmware-driven checks built into the RGA ECU. Use the Error Reporting commands to query the value of the bytes. Important: No errors are present as long as all bits in the Error Bytes are cleared. The RGA Windows software supports all the Error Reporting commands and reports the errors detected based on their Error Codes.
Error Byte Definitions 3-67 PS_ERR Error Byte: 24V P/S Error Byte. Bit Description Error Code 7 External 24V P/S error: Voltage >26V. PS7 6 External 24V P/S error: Voltage <22V. PS6 5 Not used 4 Not Used 3 Not Used 2 Not Used 1 Not Used 0 Not Used DET_ERR Error Byte: Electrometer Error Byte. Bit Description Error Code 7 ADC16 Test failure.
3-68 Error Byte Definitions QMF_ERR Error Byte: Quadrupole Mass Filter RF P/S Error Byte. Bit Description Error Code 7 RF_CT exceeds (V_EXT- 2V) at M_MAX RF7 6 Primary current exceeds 2.0A RF6 5 Not used 4 Power supply in current limited mode. 3 Not Used 2 Not Used 1 Not Used 0 Not Used RF4 CEM_ERR Error Byte: Electron Multiplier Error Byte. Bit Description Error Code 7 No Electron Multiplier Option installed EM7.
Error Byte Definitions 3-69 FIL_ERR Error Byte: Filament Error Byte. Bit Description Error Code 7 No filament detected. FL7 6 Unable to set the requested emission current. FL6 5 Vacuum Chamber pressure too high. FL5 4 Not used 3 Not used 2 Not used 1 Not used 0 Single filament operation.
Chapter 4. Trouble Shooting In This Chapter System Problems ...............................................................................................................................................................4-2 Diaphragm Pump Does Not Start .............................................................................................................................4-2 Turbo Pump Does Not Start........................................................................................................
4-2 System Problems System Problems Diaphragm Pump Does Not Start If the light next to the diaphragm pump switch on the front panel is dim, then the microcontroller is trying to run the pump. A relay click can be heard when the controller attempted to start the pump. If the click was not heard, the microcontroller or relay could have failed. If the click was heard, try venting the system to atmospheric pressure. If the diaphragm pump still does not start, the system requires service.
System Problems 4-3 Loud Noises While Shutting Down It is common to hear loud noises while the turbo pump is coasting to a stop. The pump is a vibration source which is slowly scans the frequency range from 1250 Hz to 0 Hz. Any resonances in the chassis are momentarily excited as the pump passes through the resonant frequency. These noises are normal and of no concern. Venting the system will cause the turbo pump to quickly decelerate and avoid the noise.
4-4 Internal Error Detection in the SRS RGA Internal Error Detection in the SRS RGA Several firmware-driven checks automatically test the RGA when the instrument is turned on, and continuously monitor the internal workings of the unit. A “Background Filament Protection Mode” is activated, when the filament is turned on to protect the delicate filament (and CDEM) from accidental overpressures. Several commands can be used to trigger hardware tests on the ECU.
Internal Error Detection in the SRS RGA 4-5 • • • The query command that can be used to trigger the check (see Error Reporting Commands.) The prefix of the Error Codes associated to the check. Is this check performed at power-on? 24V DC Power Supply STATUS Bit affected: 6 Error Byte affected: PS_ERR Error Reporting Command: EP? Error Codes prefix: PS Power-on check?: Yes The output of the external 24 V DC Power Supply must be between 22 and 26 Volts at all times while the RGA is in operation.
4-6 Internal Error Detection in the SRS RGA checked at any time with the query command: ED?. Several tests are performed during the check: 1. The ADC16 input is grounded and its digital output is measured to make sure it corresponds to less than 15 mV. 2. A current of +5nA is injected into the electrometer and the output is read and compared to expected values. 3. The same test is repeated with -5 nA of input current.
Internal Error Detection in the SRS RGA 4-7 Filament’s Background Protection mode STATUS Bit affected: 1 Error Byte affected: FIL_ERR Error Reporting Command: EF? Error Codes prefix: FL Power-on check?: No The filament is by far the most carefully protected component of the RGA. When a electron emission current is requested, the RGA biases the ionizer and activates the filament’s heater until the desired electron current is achieved.
4-8 Windows Software Error Codes Windows Software Error Codes A unique Error Code has been assigned to each one of the fault conditions that can be internally detected by the RGA Head. The Error Codes are used only by the RGA Windows program to report all internally detected errors. This section lists causes and troubleshooting procedures for all the possible Error Code values available in the SRS RGA.
Windows Software Error Codes 4-9 Troubleshooting: Contact SRS. DET5 Type of Error: Electrometer Error Message: Electrometer Error: DETECT fails to read -5nA input current. Error Cause: The logarithmic output of the picoammeter is not within the levels expected for a -5 nA input current. Troubleshooting: Contact SRS. DET6 Type of Error: Electrometer Error Message: Electrometer Error: DETECT fails to read +5nA input current.
4-10 Windows Software Error Codes EM7 Type of Error: Electron Multiplier Error Message: Electron Multiplier Error: No Electron Multiplier Option available in this head. Error Cause: A function involving the electron multiplier was invoked in a unit that does not include the CDEM option. Troubleshooting: Do not use any of the CDEM related commands in this unit. Upgrade the RGA to an Electron Multiplier option (Opt01). FL6 Type of Error: Filament “Background Protection Mode”.
Windows Software Error Codes 4-11 If a short is detected, remove the probe from the vacuum system , inspect the ionizer and fix any shorts. Note: Use the information in the RGA Maintenance chapter to remove the repeller and/or service the ionizer. If the short is still present after that, remove the RGA Cover Nipple and inspect the rest of the probe for other sources of shorts (i.e. misalignments, loose screws, etc.). If no short is detected, the Thoria coating of the filament might be damaged.
4-12 Windows Software Error Codes Troubleshooting: Check the voltage output of the external power supply with a voltmeter. Adjust the voltage to 24 V in adjustable external supplies or replace the power supply altogether if necessary. Contact SRS for units with a built-in power supply (Option Opt02). PS7 Type of Error: 24VDC P/S. Error Message: External 24V P/S error: Voltage >26V. Error Cause: Voltage output of 24VDC Power Supply exceeds the acceptable 22-26V DC range.
Windows Software Error Codes 4-13 Error Cause: The circuit that drives the primary of the RF Transformer is delivering an unusually large current. Troubleshooting: Check for a short in the quadrupole connections. RF7 Type of Error: Quadrupole Mass Filter RF P/S. Error Message: RF P/S Error. RF_CT exceeds (V_EXT-2V) at M_MAX. (M_MAX=100 for the RGA100, 200 for RGA200 and 300 for RGA300) Error Cause: The RF P/S goes out of regulation when the quadrupole mass filter is programmed to M_MAX amu.
4-14 Windows Software Error Codes continuously for a long time. Note: During the warm-up period, RGA Windows users should see that the mass range over which the RGA can be operated reliably increases with time until it goes beyond the user’s requested scan range. No more warnings are posted beyond that point. If no improvement in the mass range is seen as the unit warms up then go on with the troubleshooting procedure.
Chapter 5. Service The QMS contains no user serviceable parts. The service information in this chapter is intended for the use of Qualified Service Personnel. Read and understand the warnings on the following page. Read the procedures carefully and prepare by having proper tools available. In This Chapter Warnings!...........................................................................................................................................................................5-2 Component Notes ....
5-2 Warnings! Warnings! • • • • • • • • • • • The service information in this chapter is for the use of Qualified Service Personnel. To avoid shock, do not perform any procedures in this chapter unless you are qualified to repair electronic and vacuum equipment. Read and follow all Warnings before servicing the product. Dangerous voltages, capable of causing injury or death, are present in this instrument. Use extreme caution whenever servicing any of its parts.
Component Notes 5-3 Component Notes Gas Handling Components The QMS system is designed to require low maintenance. A regular maintenance schedule will not extend the life of the components. The pumps are intended to be used until they fail. At such time factory service or kits are available. The sections below discuss methods for diagnosing the performance of the major components of the system (the RGA is discussed in its manual). Turbo Pump The turbo pump is permanently lubricated.
5-4 Component Notes doubled to 2 mbar. The turbo pump can easily tolerate exhaust pressures up to 5 mbar, so the performance of the diaphragm pump is still acceptable in this example. The pumps contains two components that are most likely to fail: valves and membranes. The valves tend to wear resulting increased backing line pressure (decreased compression ratio). The membranes tend to fail suddenly by tearing and result in the pump being unable to achieve usable vacuums.
Component Notes 5-5 CDEM Handling and Care Continuous Dynode Electron Multipliers (CDEM) have a history of high performance and dependability in mass spectrometry applications. By following the simple recommendations described below the user should achieve a long useful lifetime from these detectors. Handling and mounting • • • • Handling and mounting of the CDEM should only be performed in a clean vacuum fashion. Work on a clean dust-free area. Avoid dust, lint and any kind of particulate matter.
5-6 Component Notes liquid nitrogen traps with diffusion pumps (particularly for silicone oil based pumps) , and molecular sieves traps with mechanical roughing pumps whenever possible. If the multiplier becomes contaminated it must be cleaned immediately! (See CDEM Refreshment procedure in this chapter) Storage CDEM’s can be stored indefinitely in a clean dry container such as an air or dry nitrogen-filled “dry box”.
Accessing Internal Components 5-7 Accessing Internal Components The first step to all of the service procedures in the cleaning or replacement sections is opening the QMS chassis. This involves removing the aesthetic covers. Have the QMS turned off, cooled, and vented to atmospheric pressure before beginning. After that, various components can be worked on as described in later sections. All the sections below describe how to disassemble the system.
5-8 Accessing Internal Components Internal View Map of Internal Components SRS QMS Gas Analyzer
Accessing Internal Components 5-9 Removing the RGA ECU The RGA ECU is supported between the front panel and the probe body. After following the “Opening the Chassis” section above, this procedure can be performed. Reverse the procedure to reattach the ECU. Equipment • • Phillips screwdriver 5/16 socket driver and ratchet wrench Procedure 1. Remove the wires from the power switch. These connectors are very secure and require much force to remove (as they should).
5-10 Accessing Internal Components • • • • Work in a clean dust-free area. Avoid dust, lint and any kind of particulate matter. Wear talc-free rubber gloves or finger cots. Use properly degreased tools. Avoid excessive shock, such as from dropping onto a hard surface (Remember that the CDEM is made out of glass). Equipment • • • 1 or 2 copper gaskets for 2 3/4 CF flange 1/4 inch 12 point box wrench two 7/16 inch open end wrenches Procedure 1.
General Checks 5-11 General Checks Leak Testing The seals in the system will have a long life. The metal seals will last indefinitely under normal usage. Only severe force or corrosion will cause them to fail. Elastomeric seals can eventually degrade. The integrity of these seals can be assured using the leak testing mode of the RGA software. Helium or other gases can be used, e.g. argon, or tetrafluoroethane. The CF flanges and VCR fittings have leak testing ports.
5-12 General Checks to install a second gauge in the inlet fitting of the QMS. The two gauges are then compared to see if the internal gauge is correct. Note that the gauge is a thermocouple type gauge and its sensitivity will vary significantly with the composition of the gas being measured. It is calibrated for air or nitrogen. Its sensitivity deviates significantly for helium, hydrogen, krypton, and some Freons.
Cleaning 5-13 Cleaning The most general method of cleaning the QMS is to use the vacuum pumps to remove contaminants. The inlet section is cleaned by installing a plug in the Ultra-Torr fitting and opening both valves. This will cause the pumps to continually draw on these surfaces. In severe contamination cases, more aggressive steps may be required. Bake-out Periodic high temperature bakeout can be used to clean the interior surfaces of the QMS system.
5-14 Cleaning 2. Wrap a heating tape or heating jacket around the vacuum chamber. Make sure the entire probe, including flanges, is evenly covered. 3. Start the pumps and have both pumps operating. The inlet should be plugged with and both valves open. 4. Bake the system for several hours. Monitor the bakeout to make sure the turbo pump stays cool. 5. After bakeout wait for the probe to cool down to room temperature before mounting the ECU back on its flange. 6. Run the peak tuning procedure.
Cleaning 5-15 Warning: The fumes from isopropyl alcohol can be dangerous to health if inhaled and are highly flammable. Work in well ventilated areas and away from flames. Warning: Read and follow all directions and warnings of the ultrasonic cleaner regarding the use of organic solvents for cleaning. Equipment • • • • • • Ultrasonic cleaner Isopropyl alcohol, electronic grade or better. 1000 ml beaker Oil-free, dry nitrogen Petri dish. Clean oven ( higher than 100°C setting). Procedure 1.
5-16 Cleaning • • • • • The exact alignment of the rods in the quadrupole is essential to the optimum performance of the RGA. Do not scratch the surface of the rods. Do not remove excessive amounts of surface material with the abrasives. Use clean tools and procedures. The fumes from acetone and methanol can be dangerous to health if inhaled and are highly flammable. Work in well ventilated areas and away from flames. Equipment • • • • • • • • • • • • • • • • • Clean, dust-free work area.
Cleaning 5-17 Figure 1 Probe Removal for Quadrupole Filter Cleaning 6. Carry the probe to a clean, dust free area immediately. Avoid contamination using handling procedures compatible with high vacuum requirements. 7. Hold the probe in a secure upright position and do a thorough visual inspection of the unit. Check for loose, damaged, misaligned and severely contaminated components.
5-18 Cleaning grit down to 12000 until the metal surface has a fine polished appearance. Warning: Do not remove excessive material from the surface of the precision-ground rods. 14. After all metal surfaces have been polished, they must be cleaned to remove all the abrasive compound from their surface. Begin by placing the rods in a beaker with a 1:4 solution of “Mr. Clean” detergent in water.
Cleaning 5-19 16. Visually inspect the probe to make sure all the parts are in place and correctly aligned. Use an ohmmeter to make sure the electrodes are electrically isolated from each other and from the body of the flange (ground). 17. Once satisfied, install the probe back in the vacuum system and perform a complete “Probe Bakeout” before using the RGA for measurements. 18. Perform a peak tuning procedure on the unit.
5-20 Component Replacement Component Replacement Ionizer Replacement As the RGA is used, deposits form on the ionizer parts and the sensitivity of the sensor is degraded. Once the sensitivity of the spectrometer is significantly affected by this buildup it is necessary to completely replace the ionizer. All components of the ionizer should be replaced together at once. The replacement procedure is simple and should only take a few minutes.
Component Replacement 5-21 Figure 2 Probe Removal for Ionizer Replacement 6. Carry the probe to a clean, dust free area immediately. Avoid contamination using handling procedures compatible with high vacuum requirements. 7. Hold the probe in a upright position and do a thorough visual inspection of the unit. Check for loose, damaged, misaligned and contaminated components. 8.
5-22 Component Replacement 16. Attach the new repeller to the longer filament rod using a fresh screw. Align the cage and tighten the screw (Correct alignment is best assured when the two small holes on the side of the repeller cage line up with the filament screws.) 17. Inspect visually the entire ionizer assembly to assure the correct alignment of its parts, and, if satisfied, mount the probe back on the vacuum system. Check the correct rotational orientation of the feedtrhu flange (i.e.
Component Replacement 5-23 Filament Replacement The filament eventually wears out and needs to be replaced. The replacement procedure is simple and can be completed in a few minutes by qualified personnel. The filament is very delicate and should be handled with extreme care. The thoria coating is very delicate and can easily be damaged if the filament is mishandled.
5-24 Component Replacement Figure 3 Probe Removal for Filament Replacement 6. Immediately carry the probe to a clean, dust-free area and secure it in an upright position. Avoid contamination using handling procedures compatible with high vacuum requirements. 7. Using the clean, flat-head screwdriver remove the single screw that connects the repeller to the longer filament rod and pull out the cage exposing the filament and the anode grid. 8.
Component Replacement 5-25 repeller and anode grid and need to be corrected. Use gentle pressure on the filament wire to bend it back into its correct shape if needed (Note: use a clean cotton swab for this procedure). 16. Attach the repeller to the longer filament rod using a fresh screw. Align the cage and tighten the screw (Correct alignment is best assured when the two small holes on the side of the repeller cage line up with the filament screws.) 17.
5-26 Component Replacement 2. Set up in advance a clean dust-free working area where to carry out this procedure. 3. Turn off the RGA and disconnect the ECU from the probe. 4. Wait for the probe to cool down for at least 30 minutes after the emission is turned off. Severe burns can result if the probe is handled too soon. 5.
Component Replacement 5-27 contacts. A plate (CDEM Anode ) mounted at the exit of the CDEM collects the secondary electrons. The whole assembly is self aligning. Figure 5 CDEM Replacement 9. Using the clean flat head screwdriver, remove the small screw that fastens the clamp to the HV rod and rotate the entire multiplier about its axis until the clamp’s end points away from the FC Shield. 10. Holding on to the clamp’s end, pull the multiplier out of the clip. 11. Unpack the new multiplier.
5-28 Replacement Parts Replacement Parts Some of the parts discussed in the previous sections are widely available. For users who wish to obtain replacement parts directly, the following manufacturers part numbers will be needed. Nupro and Cajon parts are carried by your local Swagelok distributor.
Factory Service 5-29 Factory Service The procedures described in this chapter are designed to guide the user through the various steps needed to maintain and/or repair the different components of the QMS instrument. These procedures should only be carried out by qualified personnel who fully understand the instrument. Users who do not feel comfortable or simply do not have the time to go through the different maintenance steps can choose to send the unit back to the factory for out-of-warranty service.
Appendix A. System Electronics In This Chapter Description of Schematics ............................................................................................................................................. A-2 Schematic: MCA_C1................................................................................................................................................ A-2 Schematic: MCA_C2.............................................................................................................
A-2 Description of Schematics Description of Schematics Control of the system originates from the microcontroller board mounted to the inside top of the chassis. This board controls the pumps, valves, and pressure gauge. The board consists of two parts: the main board and the display board. The main board contains four additional standoffs in the center of the board. They thermally connect the board to the chassis and provide additional heat sinking for the voltage regulators and solenoid drives.
Description of Schematics A-3 Schematic: MCA_C2 The relay and two solenoid valves have 24 VDC coils. The relay draws very little power and uses a simple drive circuit. Comparator U3A buffers the value from 5 V logic to 0-24 V. The pull-down resistor assures that the relay will be off during power up. The regulator, U6, drives the relay. In this application, it is used as a transistor with the added benefit of over-current limits and thermal protection. The solenoid valves consume significant power.
A-4 Parts List Parts List Microcontroller Board and Chassis Assembly Parts List REF. SRS part# VALUE DESCRIPTION C1 5-00011-501 27P Capacitor, Ceramic Disc, 50V, 10%, SL C2 5-00011-501 27P Capacitor, Ceramic Disc, 50V, 10%, SL C3 5-00225-548 .1U AXIAL Capacitor, Ceramic, 50V,+80/-20% Z5U AX C4 5-00225-548 .1U AXIAL Capacitor, Ceramic, 50V,+80/-20% Z5U AX C5 5-00100-517 2.2U Capacitor, Tantalum, 35V, 20%, Rad C6 5-00100-517 2.
Parts List A-5 J7 1-00250-116 2 PIN, WHITE Header, Amp, MTA-156 J8 1-00037-130 16 PIN DIL Connector, Male PC1 7-00748-701 QMS CONTROLLER Printed Circuit Board R1 4-00088-401 51K Resistor, Carbon Film, 1/4W, 5% R2 4-00088-401 51K Resistor, Carbon Film, 1/4W, 5% R3 4-00088-401 51K Resistor, Carbon Film, 1/4W, 5% R4 4-00088-401 51K Resistor, Carbon Film, 1/4W, 5% R5 4-00088-401 51K Resistor, Carbon Film, 1/4W, 5% R6 4-00088-401 51K Resistor, Carbon Film, 1/4W, 5% R7 4-0008
A-6 Parts List U 11 3-00546-340 HDSP-4830 Integrated Circuit (Thru-hole Pkg) U 12 3-00546-340 HDSP-4830 Integrated Circuit (Thru-hole Pkg) U 13 3-00103-340 LM3914 Integrated Circuit (Thru-hole Pkg) U 14 3-00103-340 LM3914 Integrated Circuit (Thru-hole Pkg) Y1 6-00010-620 4.
Parts List A-7 Z0 1-00316-113 8 PIN, 18AWG/OR Connector, Amp, MTA-156 Z0 1-00317-179 2 PIN PLUG Connector Housing, Receptacle Z0 1-00318-179 2 PIN RECPTCL Connector Housing, Receptacle Z0 2-00044-211 1901.
Appendix B RGA Circuit Description This chapter describes the electronics circuits located inside the Electronics Control Unit of the RGA. There are no electronic components inside the RGA Probe. The information in this chapter is provided for the use by qualified technical personnel during service and repairs. • Warnings The ECU is to be serviced by qualified technical personnel only. There are no user serviceable parts inside.
B-2 Overview of the RGA Schematic name: QMSE_V1................................................................................................................................... B-15 Signal Conditioning.......................................................................................................................................... B-15 Schematic name: QMSE_V2...................................................................................................................................
Overview of the RGA B-3 Overview of the RGA The SRS RGA is a mass spectrometer consisting of a quadrupole probe, and an Electronics Control Unit (ECU) which mounts directly on the probe’s flange. The quadrupole probe is a mass spectrometer sensor consisting of an ion source, a quadrupole mass filter, a Faraday cup and an optional electron multiplier. Ions are created from the residual gas of a vacuum system by electron impact ionization.
B-4 Circuit Description Circuit Description General Description The specifications and features of the many circuits that drive the RGA are determined by characteristics of the quadrupole mass spectrometer such as: • the ionizer settings available to the user, • the characteristics of the quadrupole mass filter, • the magnitude of the ion current levels detected during measurements, • an optional electron multiplier.
Circuit Description B-5 multiplier may be used. The electron multiplier needs to be biased with as much as -2500VDC to provide gains as large as 107. Circuit Boards There are two main PCBs inside the ECU package. The top PCB has the CPU, RS232, digital ports, the analog electronics for A/Ds and D/As, and the RF amplitude detection circuit. A small vertical PCB which holds the log I/V converter connects to the top PCB. A second small vertical PCB holds the electron multiplier’s HV supply.
B-6 Description of Schematics Description of Schematics Schematic name: QMSE_T1 Microprocessor An MC68HC11E9 microcontroller is used to control the system and to communicate with the host computer. This central processing unit (CPU) also has RAM, ROM, EEPROM, UART, octal 8-bit A/D converter, counter timers, and a multiplexed address/data bus to accommodate an external 32Kx8 RAM. The ROM is used for program storage, the RAM for data storage, the EEPROM contains calibration values for the particular unit.
Description of Schematics B-7 PD0 RXD RS232 data received from host computer. PD1 TXD RS232 data transmitted to host computer. PD2 SPI_IN Serial peripheral interface data from 16-bit A/D converter. PD3 SPI_OUT Serial peripheral interface data to 8 and 18-bit D/A converters. PD4 SPI_CLK Serial peripheral interface data clock. PD5 -CTS Low to allow host computer to send RS232 data. PE0 +24/6 A/D input: +24VDC supply divided by 6. PE1 RF_CT/5 A/D input: RF primary voltage divided by 5.
B-8 Description of Schematics Q2 CAL_2 multiplexer. Q3 MPX_0 Q4 MPX_1 Q5 MPX_2 Q6 EMIT_CTL Q7 GRID_SEL MSB of current detector calibration attenuator LSB of 16-bit A/D converter's input multiplexer. Middle bit of 16-bit A/D converter's input multiplexer. MSB of 16-bit A/D converter's input multiplexer. Filament heater duty cycle control: 0=direct, 1=regulate Low for low grid potential, high for high grid potential. The MISC port Q0 Q1 gnd.
Description of Schematics B-9 RS232 Interface The microcontroller communicates with a host computer via the RS232 interface. The RS232 interface is configured as a DCE (data communications equipment) at a fixed baud rate of 28.8k, with hardware handshaking via CTS (clear-to-send) and RTS (request-to-send), and uses a PC compatible female DB9 connector. So, the quadrupole will transmit data on pin 2, receive data on pin 3, assert CTS on pin 8, and look for RTS on pin 7.
B-10 Description of Schematics -IRQ, the CPU sets CS_VETO high (which sets -CS_ADC16 high) and sets R/-C high to allow the data to be read. The -BUSY output will remain low for up to 20µs during a conversion. When -BUSY goes high, the CPU returns CS_VETO low, which again asserts the -CS_ADC16 (this time with R/-C high), and reads the data from the ADC via the SPI. Since the ADC shifts its data on the rising edge of the data clock (i.e.
Description of Schematics B-11 RF Amplitude Detection The amplitude of the RF is detected by a full-wave charge pump detector. In order to provide a symmetrical load to the generator, the amplitude on both rods is detected and summed. The charge pump works as follows: as the potential on the rod reaches a peak, the 0.5 pF capacitor (C750 on the PCB which holds the flange socket) is charged to the maximum voltage, Vp + Vdc - Vdiode with current flowing to ground via D303, a Schottky diode.
B-12 Description of Schematics The 18-bit DAC output is also used to set the DC potentials applied to the mass filter. RF_SET is multiplied by 4 by the differential amplifier U304A, which uses the bottom PCB for its ground reference. The output of U304A is passed to the bottom PCB via JP301 to control the DC bias sources. Schematic name: QMSE_B1. Mass filter RF Supply The Toroid: The design approach was dominated by the characteristics of the RF transformer.
Description of Schematics B-13 with the correct amplitude and phase into the primary drive inductor, T401, to cancel the charge injected via the FET gates. DC Potentials In addition to the RF, DC potentials of about ±1/12th the RF peak-to-peak value is required for the two rod pairs. The op-amp U403A is the error amplifier which maintains the negative potential equal to a fraction of the set RF level.
B-14 Description of Schematics DE_GAS bit) to the voltage seen on the 100Ω emission current shunt resistor, R522. (The current sensed by this resistor is actually composed of three components: the filament emission current, the repeller voltage/100kΩ, and Vref (+5V)/30kΩ. All of these components sum. With a repeller voltage of -60V, the two non-emission sources sum to 0.60+0.166=0.766mA. So, to set an emission current of 2mA, EMIT_SET, which provides 1mA/V, is set to 2.766VDC.
Description of Schematics B-15 For a high power de-gas, a DPDT relay is used to by-pass the bias regulators, connecting the grid and repeller directly to the un-regulated +250Vdc and -150Vdc supplies. During de-gas, the filament emission current is set to 20mA, which will provide about 8W of power to heat the grid, in addition to 15W of filament heater power. Schematic name: QMSE_B3 Power Supplies The unit is operated from +24VDC, and requires up to 2.0A.
B-16 Description of Schematics lowest current which may be detected. Extreme care is required to achieve low drift and low noise current measurements at these very low current levels. In addition, the instrument needs to measure a wide range of pressures, which requires current measurements over a wide range. The sensitivity of the ionizer and mass filter is about 100µA/Torr, and is nearly constant from 0 to 5x105 Torr, so we expect ion currents from 0 to 5nA.
Description of Schematics B-17 Schematic name: QMSE_V2 Electron Multiplier High Voltage Power Supply The electron multiplier option extends the operation of the RGA to much lower pressures. By multiplying the ion current before detection in the I/V converter, the signal to noise ratio is not affected by the bias current noise of the I/V converter. Since the gain of the electron multiplier varies rapidly with applied bias, well regulated negative high voltage supply is required.
B-18 Parts Lists Parts Lists Top Board Parts List REF. SRS part# VALUE DESCRIPTION C 100 5-00023-529 .1U Cap, Monolythic Ceramic, 50V, 20%, Z5U C 101 5-00221-529 330P Cap, Monolythic Ceramic, 50V, 20%, Z5U C 102 5-00221-529 330P Cap, Monolythic Ceramic, 50V, 20%, Z5U C 103 5-00285-562 100P Cap., NPO Monolitic Ceramic, 50v, 5% Ra C 104 5-00285-562 100P Cap., NPO Monolitic Ceramic, 50v, 5% Ra C 105 5-00285-562 100P Cap., NPO Monolitic Ceramic, 50v, 5% Ra C 106 5-00023-529 .
Parts Lists B-19 C 303 5-00239-562 680P Cap., NPO Monolitic Ceramic, 50v, 5% Ra C 304 5-00233-532 22P Capacitor, Ceramic Disc, 50V, 10% NPO C 305 5-00239-562 680P Cap., NPO Monolitic Ceramic, 50v, 5% Ra C 306 5-00023-529 .
B-20 Parts Lists Q 104 3-00021-325 2N3904 Transistor, TO-92 Package Q 105 3-00021-325 2N3904 Transistor, TO-92 Package Q 106 3-00021-325 2N3904 Transistor, TO-92 Package R 100 4-00192-407 49.9K Resistor, Metal Film, 1/8W, 1%, 50PPM R 101 4-00138-407 10.0K Resistor, Metal Film, 1/8W, 1%, 50PPM R 102 4-00887-407 133K Resistor, Metal Film, 1/8W, 1%, 50PPM R 103 4-00138-407 10.0K Resistor, Metal Film, 1/8W, 1%, 50PPM R 104 4-00079-401 4.
Parts Lists B-21 R 210 4-00192-407 49.9K Resistor, Metal Film, 1/8W, 1%, 50PPM R 211 4-00142-407 100K Resistor, Metal Film, 1/8W, 1%, 50PPM R 212 4-00142-407 100K Resistor, Metal Film, 1/8W, 1%, 50PPM R 213 4-00192-407 49.9K Resistor, Metal Film, 1/8W, 1%, 50PPM R 214 4-00142-407 100K Resistor, Metal Film, 1/8W, 1%, 50PPM R 215 4-00138-407 10.0K Resistor, Metal Film, 1/8W, 1%, 50PPM R 216 4-00130-407 1.
B-22 Parts Lists R 316 4-00021-401 1.0K Resistor, Carbon Film, 1/4W, 5% R 317 4-00188-407 4.99K Resistor, Metal Film, 1/8W, 1%, 50PPM R 318 4-00188-407 4.99K Resistor, Metal Film, 1/8W, 1%, 50PPM R 319 4-00164-407 20.0K Resistor, Metal Film, 1/8W, 1%, 50PPM R 320 4-00188-407 4.99K Resistor, Metal Film, 1/8W, 1%, 50PPM R 321 4-00164-407 20.0K Resistor, Metal Film, 1/8W, 1%, 50PPM R 322 0-00000-000 UNDECIDED PART Hardware, Misc. R 323 4-00079-401 4.
Parts Lists B-23 U 307 3-00633-340 MAX528CPP Integrated Circuit (Thru-hole Pkg) Z0 0-00042-010 4-40 HEX Nut, Hex Z0 0-00241-021 4-40X3/16PP Screw, Panhead Phillips Z0 1-00087-131 2 PIN JUMPER Connector, Female Bottom Board Parts List REF. SRS part# VALUE DESCRIPTION C 400 5-00049-566 .001U Cap, Polyester Film 50V 5% -40/+85c Rad C 401 5-00100-517 2.2U Capacitor, Tantalum, 35V, 20%, Rad C 402 5-00051-512 .015U Cap, Stacked Metal Film 50V 5% -40/+85c C 403 5-00023-529 .
B-24 Parts Lists C 505 5-00329-526 120U Capacitor, Electrolytic, 35V, 20%, Rad C 506 5-00264-513 .0015U Capacitor, Mylar/Poly, 50V, 5%, Rad C 507 5-00264-513 .0015U Capacitor, Mylar/Poly, 50V, 5%, Rad C 508 5-00330-533 .01U 400V 10% Capacitor, Metallized Polyester C 509 5-00330-533 .01U 400V 10% Capacitor, Metallized Polyester C 510 5-00330-533 .01U 400V 10% Capacitor, Metallized Polyester C 511 5-00023-529 .
Parts Lists B-25 D 503 3-00004-301 1N4148 Diode D 504 3-00004-301 1N4148 Diode D 505 3-00203-301 1N5711 Diode D 506 3-00004-301 1N4148 Diode D 611 3-00228-301 MUR160 Diode D 612 3-00228-301 MUR160 Diode D 613 3-00228-301 MUR160 Diode D 614 3-00228-301 MUR160 Diode D 615 3-00228-301 MUR160 Diode D 616 3-00228-301 MUR160 Diode D 617 3-00228-301 MUR160 Diode D 618 3-00228-301 MUR160 Diode D 619 3-00228-301 MUR160 Diode D 620 3-00228-301 MUR160 Diode D 62
B-26 Parts Lists PC1 7-00670-701 RGA BOTTOM Printed Circuit Board Q 400 3-00022-325 2N3906 Transistor, TO-92 Package Q 404 3-00627-325 MPSA92 Transistor, TO-92 Package Q 405 3-00628-325 MPSA42 Transistor, TO-92 Package Q 406 3-00627-325 MPSA92 Transistor, TO-92 Package Q 407 3-00628-325 MPSA42 Transistor, TO-92 Package Q 502 3-00644-329 TIP48/TIP47 Voltage Reg.
Parts Lists B-27 R 424 4-00405-407 2.49M Resistor, Metal Film, 1/8W, 1%, 50PPM R 425 4-00034-401 10K Resistor, Carbon Film, 1/4W, 5% R 426 4-00188-407 4.99K Resistor, Metal Film, 1/8W, 1%, 50PPM R 427 4-00074-401 33K Resistor, Carbon Film, 1/4W, 5% R 428 4-00022-401 1.0M Resistor, Carbon Film, 1/4W, 5% R 429 4-00034-401 10K Resistor, Carbon Film, 1/4W, 5% R 430 4-00083-401 47K Resistor, Carbon Film, 1/4W, 5% R 431 4-00890-408 1.000M Resistor, Metal Film, 1/8W, 0.
B-28 Parts Lists R 517 4-00141-407 100 Resistor, Metal Film, 1/8W, 1%, 50PPM R 518 4-00031-401 100 Resistor, Carbon Film, 1/4W, 5% R 519 4-00034-401 10K Resistor, Carbon Film, 1/4W, 5% R 520 4-00192-407 49.9K Resistor, Metal Film, 1/8W, 1%, 50PPM R 521 4-00138-407 10.0K Resistor, Metal Film, 1/8W, 1%, 50PPM R 522 4-00141-407 100 Resistor, Metal Film, 1/8W, 1%, 50PPM R 523 4-00188-407 4.
Parts Lists B-29 R 617 4-00800-401 1 Resistor, Carbon Film, 1/4W, 5% R 618 4-00058-401 220K Resistor, Carbon Film, 1/4W, 5% RL500 3-00196-335 HS-212S-5 Relay T 400 6-00009-610 T1-1-X65 Transformer T 401 6-00197-601 RF PRIMARY Inductor T 500 6-00200-610 RGA FILAMENT Transformer T 601 6-00199-610 RGA INVERTER Transformer U 400 3-00090-340 LF411 Integrated Circuit (Thru-hole Pkg) U 401 3-00286-340 SN75372 Integrated Circuit (Thru-hole Pkg) U 402 3-00508-340 LM358 Integra
B-30 Parts Lists Vertical Board Parts List REF. SRS part# VALUE DESCRIPTION C 700 5-00023-529 .1U Cap, Monolythic Ceramic, 50V, 20%, Z5U C 701 5-00023-529 .1U Cap, Monolythic Ceramic, 50V, 20%, Z5U C 750 5-00339-574 .5P 500V SMT SMT, High Voltage Porcelain Cap. C 751 5-00339-574 .5P 500V SMT SMT, High Voltage Porcelain Cap. C 800 5-00060-512 1.0U Cap, Stacked Metal Film 50V 5% -40/+85c C 801 5-00100-517 2.
Parts Lists B-31 D 810 3-00626-301 MUR1100E Diode D 811 3-00626-301 MUR1100E Diode D 812 3-00004-301 1N4148 Diode J 701 1-00268-120 PUSH-ON RG58 Connector, BNC JP700 1-00266-130 20 PIN DI RA Connector, Male JP750 1-00271-131 4 PIN SI SIDE Connector, Female JP751 1-00271-131 4 PIN SI SIDE Connector, Female JP752 1-00267-130 4 PIN SI RA Connector, Male JP800 1-00263-130 20 PIN DI Connector, Male JP850 1-00264-131 20 PIN DI Connector, Female JP852 1-00266-130 20 PIN D
B-32 Parts Lists R 705 4-00193-407 499 Resistor, Metal Film, 1/8W, 1%, 50PPM R 706 4-00032-401 100K Resistor, Carbon Film, 1/4W, 5% R 707 4-00031-401 100 Resistor, Carbon Film, 1/4W, 5% R 708 4-00031-401 100 Resistor, Carbon Film, 1/4W, 5% R 709 4-00032-401 100K Resistor, Carbon Film, 1/4W, 5% R 800 4-00166-407 200K Resistor, Metal Film, 1/8W, 1%, 50PPM R 801 4-00034-401 10K Resistor, Carbon Film, 1/4W, 5% R 802 4-00034-401 10K Resistor, Carbon Film, 1/4W, 5% R 803 4-00074-
Parts Lists B-33 Z0 0-00308-021 4-40X7/8PP Screw, Panhead Phillips Z0 0-00316-003 PLTFM-28 Insulators Z0 0-00317-000 40MM 24V Hardware, Misc. Z0 0-00551-000 40MM FAN GUARD Hardware, Misc. Z0 0-00588-030 #4X5/16" Spacer Z0 0-00589-026 4-40X5/16"PF Screw, Black, All Types Z0 0-00614-021 4-40X1-1/4PP Screw, Panhead Phillips Z0 0-00617-031 4-40X1-3/16 F/F Standoff Z0 0-00627-056 SOUND/AUDIO 1PR Cable, Coax & Misc.
Appendix C. Drawings & Schematics This appendix contains foldout drawings & schematics refered to in previous chapters.
Declaration of Contamination of Vacuum Equipment The repair and/or service of vacuum equipment or components can only be carried out if a completed declaration has been submitted. SRS reserves the right to refuse acceptance of vacuum equipment submitted for repair or maintenance work where the declaration has been omitted or has not been fully or correctly completed.
