Residual Gas Analyzers/Spectramass Dataquad


			Residual Gas Analyzers. Gas Analysis Systems.

The Spectramass DATAQUAD - RGA.
The Dataquad RGA is a complete 'Stand Alone' RGA system with its own mictroprocessor electronics. With a dedicated keyboard, monochrome monitor and extensive software, Dataquad offers the user exceptional performance at low cost. All Dataquads are supplied with Datapacks 1, 2 and 3 providing the main operating modes of Bar Graph, Peak Select (Channel and Trend), Analogue and Leak Detect with facilities such as logarithmic or linear display, backgrounds, library and split spectrum display. RS232 and centronics ports are standard. A separate software package is available to control and display the Dataquad from a PC Computer, which offers many additional facilities including datalogging and data recall/review. Refer to supplementary leaflet for further information.
	The Analyser. The quadrupole analyser is available with a choice of ion sources, mass filters and detection systems. The standard ion source is a radially symmetrical design fitted with twin filaments and suits most applications. The standard filaments are tungsten but thoria coated iridium are available if required.
The R.F. Head/Pre-amp. This compact unit contains the pre-amplifier and RF generation/control electronics and plugs directly onto the analyser to prevent signal degradation. The standard cable length is 2 metres but extension cables up to 100 metres can be supplied if required.
The Control Unit. The control unit contains all the main power supplies, microprocessor and interface electronics mounted on 3 plug-in easily replaceable circuit cards. The unit also contains a 9" display monitor and a dedicated membrane key panel to provide a complete 'stand alone' RGA system housed in a 5U high 19 inch rack module.
Software description
BarGraph Mode This display mode of mass versus partial pressure gives a bar representation (spectrum histogram) of the peaks detected during a scan. The operator can select the first mass, display scan, precision code, mass identify cursor and full span. There are 6 precision codes giving a choice of speed/accuracy combinations, and the gain may be controlled manually or automatically by the microprocessor. The total pressure can be enabled/disabled as a menue option and when enabled, the value is displayed on the top right hand corner of the VDU.
Peak Select. The Peak Select mode offers an alternative to scanning all the masses sequentially and enables up to 16 masses to be monitored in table format and upto 8 masses in histogram form. The two modes being toggled by the Table/Graph key. The operator has control over mass, gain (or auto), detector and alarm levels for each individual channel making Peak Select a powerful aid to vacuum analysis. When alarms are activated, signals are available as TTL levels on the rear panel, for process monitoring applications.
Index (Menue Options). The Dataquad can be operated in the modes mentioned above without entering the index. There are however some useful additional functions available which are accessed by first entering Index and then moving the cursor to the function required and making the selection by pressing the enter key.	Split Screen When selected with the bar graph mode, the screen display area is split into two sets of axes. The top set shows the current mass spectrum, whilst the lower displays the mass spectr library with the facility to step through the individual spectra for comparison purposes. Alternatively using the background display key, any of the four user stored spectra can be reviewed. An autosearch is provided allowing the user to select a peak in the current bar graph spectrum which is then compared to the mass spectra library, and any matches are sequentially displayed on the screen. Multiplier Calibration. Measures mass 28 with the faraday detector, switches on the multiplier and adjust the gain to a factor of 100.
Trend Analysis. This display option allows the partial pressures of upto 8 masses to be plotted against time. The plot interval can be selected from i second to 10 minutes and the values may be shown on the VDU as numerical entries in 8 columns or as horizontal bars in each mass column, the length of which depends on the partial pressure. The table/Graph key is used to toggle between the two alternative display formats.
Analogue Display. This is mainly used for checking on the analyser condition. It allows the peak shape and resolution of the analyser to be monitored and also simplifies the checking of mass alignment.	Reset. Returns programmed values of each mode to the factory set values. Pressing a second time returns to user values.
Diagnostics Automatic check of main power supplies. Out of specification supplies are indicated by a fail code message. Details are in the operators manual.	Max Peaks. Operates from any mode. Bar graph is automatically selected and the 8 largest peaks are located, loaded sequentially into the peak select programme and then Dataquad then runs in Peak Select mode.
Protect. User may select Total and/or partial pressure trip. Total pressure trip operates in bar graph mode only when reading reaches 10 x 10-6 torr. Partial pressure trip operates in any scanning mode when a peak exceeds full scale. Both trips switch off the filament.	Auto-Run. On activation, a confirmation that vacuum is O.K. is requested. The filament is then switched on and a 15 minute warm up time will elapse. Then the diagnostics routine is activated followed by operation in the last used mode.
Timed Printout. The operator may select via the print key either 'single' or 'timed' print. In timed mode, the time interval set (max 99 mins) is activated to provide a printout of screen display after the interval has elapsed.	Filament 1 and 2. The keys select filament 1 or filament 2, a second press on the key switching the filament off.
Print. Provides a single printout at the end of the scan onto a printer. Background Store. Allows the user to store any one mass spectrum from the Bar graph mode.	Leak Detect. Sets the quadrupole to mass 4 and displays a graph of mass 4 signal versus time. ENABLE/DISABLE switches off the audio tone. Manual control of gain is available. The mass may be programmed and is remembered for subsequent selection of this mode.
Background Display Recalls and displays the stored spectrum. Scanning restarted by pressing the STOP/RUN key (or a function key).	SEM. (Dual Detector only) Selects the electron multiplier with gain of 100. Note that Total Mode is still provided in this mode, when enabled from the index.
Background Subtract. Subtracts the store spectrum from the 'on-line' spectrum in bar graph mode.	3-Decade Display. This display format is available in bar graph mode, plotting peak heights over any 3 consecutive decades of gain in a logarithmic type display. With this dynamic range of 1000 to 1, large and small peaks may be displayed on the same axis.
Degas. To degas Ion Source with user setting of degas time.

Technical Data.
Mass Range	1-100, 2-200.
Resolution	10% valley between equal peaks.
Minimum detectable partial pressure	2x10-11mBar Faraday, 2x10-13mBar SEM
Minimum detectable total pressure	1 x 10-11 mBar.
Maximum operating pressure	1x10-4mBar Faraday, 1x10-5mBar SEM
Electron energy	70eV
Ion Energy	6eV
Emission	1 mA *
Bake-out temperature	250C recommended. 350C maximum
R.F frequency	1.84Mhz std.
R.F. amplitude	800V p/p at maximum mass
Rod diameter	6.35 m.m.
Rod length	100 m.m. std.
Power requirements	105/115/220/240 volts 50/60Hz 50Watt
Software for PC Control	Refer to separate Software Leaflet.
Integral VDU	9" monochrome

Order Information. - Dataquad.
Complete Instruments	DAQ100DXS	100amu RGA with Faraday Detector
	DAQ100DXM	100amu RGA with Dual Detector
	DAQ200DXS	200amu RGA with Faraday Detector
	DAQ200DXM	200amu RGA with Dual Detector
Spare Analyzer Heads	AH/200F	100/200 Analyzer with Faraday Detector
	AH/200M	100/200 Analyzer with dual detector
Spare Filaments	SM100FW	Pack of 4 tungsten
	SM100FT	Pack of 2 Thoria coated Iridium

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