INFICON UL1000 Helium leak detector - Manual (Page 8)

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General Information
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1.1.2 Indications
Tipp Information on helpful procedures.
Notice: Information on special technical requirements that the user must comply
with.
The references to diagrams consists of the chapter number, figure number and the
item number in this order. For example: Fig. 2-4/7 refers to item 7 in the figure 4 of
chapter 2.
1.1.3 Symbols of Vacuum Technology
Given in the following are some important vacuum symbols which are used in this
manual.
Vacuum pump in general
Turbomolecular pump
Measuring instrument
Valve
1.1.4 Definiton of Terms
Autoranging
The range of the preamplifier and the vacuum ranges are selected automatically.
The autoranging feature of the UL1000 Fab covers the entire range or leak rates
depending on the selected operating mode. Not only the leak rate signal, but also the
pressure in the test sample (inlet pressure P1) and the forevacuum pressure (P2) are
used for control purposes. Range switching between the main ranges is performed
via valves. Fine range switching within the main ranges is implemented by switching
over the gain factor of the preamplifier.
Autotune
Mass alignment
This function automatically aligns the mass spectrometer so that a maximum leak
rate is displayed. The control processor changes the voltage which erates the ions
in the selected mass range until a maximum ion current is detected by the ion
detector. During each calibration the mass alignment is run automatically.