Specifications

Contents
SRS Residual Gas Analyzer
vi
Chapter 3 RGA Quadrupole Probe 3-1
Introduction............................................................................................................................................. 3-2
Ionizer ...................................................................................................................................................... 3-3
Description .................................................................................................................................. 3-3
Principle of operation................................................................................................................. 3-3
Parameter Settings ..................................................................................................................... 3-4
Quadrupole mass filter........................................................................................................................... 3-7
Description .................................................................................................................................. 3-7
Principle of operation................................................................................................................. 3-8
Mass Range, Resolution and Throughput ............................................................................... 3-9
Zero Blast Suppression............................................................................................................ 3-12
Ion Detector........................................................................................................................................... 3-13
Description ................................................................................................................................ 3-13
Faraday Cup operation............................................................................................................. 3-14
Electron Multiplier Operation .................................................................................................. 3-14
Hardware modifications ....................................................................................................................... 3-18
Repeller and anode grid modifications .................................................................................. 3-18
Repeller removal....................................................................................................................... 3-19
Operation without a filament ................................................................................................... 3-19
W filament replacement............................................................................................................ 3-19
RGA Cover Nipple Replacement ............................................................................................. 3-20
Chapter 4 RGA Electronics Control Unit 4-1
Introduction............................................................................................................................................. 4-2
Front Panel .............................................................................................................................................. 4-3
Rear Panel................................................................................................................................................ 4-4
+24VDC@2.5A Connector .......................................................................................................... 4-4
RS232/DCE/28.8k Connector ..................................................................................................... 4-5
LED’s............................................................................................................................................ 4-5
Locking Knobs............................................................................................................................ 4-5
Power entry module (Option 02) ............................................................................................... 4-5
LED Functionality ....................................................................................................................... 4-6
STATUS (Green) LED’s.......................................................................................................... 4-6
ERROR (Red) LED’s ..............................................................................................................4-7
Electrometer ............................................................................................................................................ 4-8
Detection limit vs. scan rate ...................................................................................................... 4-8
Adjusting the Zero of the Ion Detector ..................................................................................... 4-9