|
(read
the JVST Magazine article comparing RGA's)
The 100, 200 and 300 amu residual gas analyzers from SRS offer
exceptional performance and value. These RGA's provide detailed
gas analysis of vacuum systems at about half the price of competitive
models. Each RGA system comes complete with a quadrupole probe,
electronics control unit (ECU), and a real-time Windows
software package that is used for data acquisition and analysis,
as well as probe control.
Rugged Probe Design
The probe consists of an ionizer, quadrupole mass filter and a
detector. The simple design has a small number of parts which minimizes
outgassing and reduces the chances of introducing impurities into
your vacuum system. The probe assembly is rugged and mounts onto
a standard 2 ¾ inch CF flange. It is covered with a stainless
steel tube with the exception of the ionizer which requires just
2 ½ inches of clearance in your vacuum system—about
that of a standard ion gauge. The probe is designed using self-aligning
parts so it can easily be reassembled after cleaning.
Compact Electronics Control Unit
The densely packed ECU contains all the necessary electronics for
controlling the RGA head. It is powered by either an external +24
VDC (2.5 A) power supply or an optional, built-in power module which
plugs into an AC outlet. LED indicators provide instant feedback
on the status of the electron multiplier, filament, electronics
system and the probe. The ECU can easily be removed from the probe
for high temperature bakeouts.
Unique Filament Design
A long-life, dual thoriated-iridium (ThO2/Ir)
filament is used for electron emission. Dual ThO2/Ir
filaments last much longer than single filaments, maximizing the
time between filament replacement. Unlike other designs, SRS filaments
can be replaced by the user in a matter of minutes.
Continuous Dynode Electron Multiplier
A Faraday cup detector is standard with SRS RGA systems which allows
partial pressure measurements from 10-5
to 5 × 10-11
Torr. For increased sensitivity and faster scan rates, an optional
electron multiplier is offered that detects partial pressures down
to 5 × 10-14
Torr. This state-of-the-art macro multi-channel continuous-dynode
electron multiplier (CDEM) offers increased longevity and stability
and can also be replaced by the user—a first for RGAs!
Useful Features
All RGAs have a built-in degassing feature. Using electron impact
desorption, the ion source is thoroughly cleaned, greatly reducing
the ionizer's contribution to background noise.
A firmware driven filament protection feature constantly monitors
(675 Hz) for over pressure. If over pressure is detected, the filament
is immediately shut off, preserving its life.
A unique temperature-compensated, logarithmic electrometer detects
ion current from 10-7 to 10-15
Amps in a single scan with better than 2 % precision. This huge
dynamic range means you can make measurements of small and large
gas concentrations simultaneously.
Complete Programmability
Communication with computers is made via the RS-232 interface.
Analog and histogram (bar) scans, leak detection and probe parameters
are all controlled and monitored through a high-level command set.
This allows easy integration into existing programs.
RGA Windows Software
The RGA systems are supported with a real-time Windows
software package that runs on PCs. The intuitive graphical user
interface allows measurements to be made quickly and easily. The
program is fully interactive, giving the user complete control of
the graphical display. Screens can be split for dual-mode operation,
scales can be set to linear or log format, and data can be scaled
manually or automatically. Data is captured and displayed in real-time
or scheduled for acquisition at a given time interval for long-term
data logging. Features include user-selectable units (Torr, mbar,
Pa and A), programmable audio and visual alarms, and comprehensive
on-line help.
The software also allows complete RGA head control with easy mass
scale tuning, sensitivity calibration, ionizer setup, and electron
multiplier gain adjustment. For further analysis, data files can
be saved in ASCII format for easy transfer into spreadsheets. Graphic
images can be saved as META files or copied to the clipboard for
importing directly into other Windows programs. The software
also provides password protection for locking out head parameters
so that casual users can´t alter important settings. A LabVIEW
dirver is also available on the SRS website.
An optional stand-alone monitor (PPM100)
can be used to control the RGA without a host computer.
Multi-Head Operation
The software supports multiple head operation when more than one
RGA is needed. Up to eight ECUs can be monitored from the software.
Performance and Value
The SRS family of RGAs is ideal for applications involving gas
analysis, leak detection, and vacuum processing. We offer 100, 200
and 300 amu systems with supporting
Windows software and options that include an electron multiplier
and a built-in power module for AC line operation.
|
Specifications |
| Operational |
|
|
|
Mass range
|
|
| RGA100 |
1 to 100 amu |
| RGA200 |
1 to 200 amu |
|
RGA300 |
1 to 300 amu |
| Mass filter type |
Quadrupole |
| Detector type |
Faraday cup (FC)—standard,
electron multiplier (EM)—optional |
| Resolution |
Better than 0.5 amu @ 10 %
peak height (per AVS std. 2.3). Adjustable to constant peak
width throughout the mass range. |
| Sensitivity (A/Torr) |
2 × 10-4
(FC), <200 (EM). User adjustable throughout high voltage
range. Measured with N2 @ 28
amu with 1 amu full peak width, 10 % height, 70 eV electron
energy, 12 eV ion energy, and 1 mA electron emission current.
|
| Minimum detectable partial
pressure |
5 × 10-11
Torr (FC). 5 × 10-14
Torr (EM). Measured with N2
@ 28 amu with 1 amu full peak width, 10 % height, 70 eV electron
energy , 12 eV ion energy, and 1 mA electron emission current.
|
| Operating pressure |
10-4
Torr to UHV (FC)
10-6 Torr to UHV (EM) |
| Max. operating temp. |
70 °C |
| Bakeout temperature |
300 °C (without ECU) |
| Ionizer |
| Design |
Open ion source, cylindrical
symmetry, electron impact ionization. |
| Material |
SS304 construction |
| Filament |
Thoriated-iridium (dual)
with firmware protection. Built-in 1 to 10 W degas ramp-up.
Field replaceable. |
| 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
|
| General |
| Probe dimension |
8.75" from flange face
to top of ionizer |
| Probe insertion |
2.0" |
| Probe mounting flange |
2.75" CF |
| Minimum tube I.D. |
1.375" |
| ECU dimensions |
9.1" ×4.1"
× 3.1" (WHL) Easily separated from the probe for
bakeout. |
| LED indicators |
Power ON/OFF, filament ON/OFF,
degas ON/OFF, electron multiplier ON/OFF, RS-232 Busy, Error,
Overpressure, Burnt Filament. |
| Warm-up time |
Mass stability ±0.1
amu after 30 minutes |
| Computer interface |
RS-232C, 28,800 baud with
high-level command set |
| Software |
Windows based application |
| Power requirement |
24 VDC @ 2.5 amps. Male
DB9 connector. Optional 110/120/220/240 VAC adapter. |
| Weight |
6 lbs. |
| Warranty |
One year parts and labor
on defects in materials and workmanship |
Stanford Research Systems, Inc. • 1290-D
Reamwood Ave., Sunnyvale, CA 94089
Phone: (408) 744-9040 • Fax: (408) 744-9049 • email: info@thinkSRS.com
• www.thinkSRS.com
© Stanford Research Systems, Inc. 2003
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