Specifications

Contents
SRS Residual Gas Analyzer
xii
Chapter 10 RGA Circuit Description 10-1
Overview of the RGA............................................................................................................................ 10-3
Circuit Description................................................................................................................................ 10-4
General Description.................................................................................................................. 10-4
Circuit Boards ........................................................................................................................... 10-5
Description of Schematics................................................................................................................... 10-6
Schematic name: QMSE_T1 .................................................................................................... 10-6
Microprocessor....................................................................................................................... 10-6
Digital I/O Ports...................................................................................................................... 10-6
The LED port.......................................................................................................................... 10-7
The MPX port......................................................................................................................... 10-7
The MISC port........................................................................................................................ 10-7
Clocks..................................................................................................................................... 10-7
RS232 Interface...................................................................................................................... 10-8
Schematic name: QMSE_T2 .................................................................................................... 10-8
I/V calibration......................................................................................................................... 10-8
A/D Conversion...................................................................................................................... 10-8
Power-up Conditioning........................................................................................................... 10-9
Schematic name: QMSE_T3) ................................................................................................... 10-9
DC Control Voltages .............................................................................................................. 10-9
RF Amplitude Detection....................................................................................................... 10-10
RF Amplitude Control.......................................................................................................... 10-10
Foldback Current Limiting................................................................................................... 10-10
Schematic name: QMSE_B1. ................................................................................................. 10-11
Mass filter RF Supply........................................................................................................... 10-11
DC Potentials........................................................................................................................ 10-12
Schematic name: QMSE_B2. ................................................................................................. 10-12
Filament Heater Supply........................................................................................................ 10-12
Bias Regulators..................................................................................................................... 10-13
Schematic name: QMSE_B3 .................................................................................................. 10-14
Power Supplies ..................................................................................................................... 10-14
Schematic name: QMSE_V1 .................................................................................................. 10-14
Signal Conditioning.............................................................................................................. 10-14
Schematic name: QMSE_V2 .................................................................................................. 10-16
Electron Multiplier High Voltage Power Supply................................................................. 10-16
Chapter 11 RGA Probe Assembly
RGA Probe Assembly Schematic......................................................................................................... 11-3
Feedthru Flange Connectors Schematic............................................................................................. 11-4
O100MAX Maximum Insertion Nipple Drawing................................................................................... 11-5
Appendix A Vacuum Diagnosis with SRS RGA’s