MKS Spectra 138A, Инструкция по эксплуатации

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PAS Trolley Manual
LP101017 Rev 1.02
Page 22
4.7. Inlet System
The RGA analyser can be connected to the vacuum system to be
tested in several ways:
•
Via a flexible vacuum connection from the analyser (Conflat
flange) with the analyser mounted in the case.
•
With the analyser mounted directly on the vacuum system
under test (remotely from the base unit or ‘cart’).
•
Using the atmospheric inlet system.
The three methods of operation are described below.
4.8. Operation via flexible connection
The valve system on the instrument terminates in a DN CF40 (2¾
inch ‘Conflat’) flange. It is recommended that stainless steel bellows
be used to connect the flange to the chamber under test.
It is good practice to minimise the length of the bellows to avoid
water contamination from the inside surface of the bellows. The
bellows can be evacuated by either the RGA system pumps or
preferably the system pumps prior to use.
The RGA system has a dual valve inlet. This gives a wide operating
pressure for the system but requires manual adjustment to set the
pressure in the RGA head correctly. In general, for process pressures
between 1x10
-3
mbar and UHV the needle valve and needle isolation
valve should be closed and the high conductance inlet valve opened
and adjusted to give a pressure indicated on the instrument cold
cathode gauge of better than 5x10
-5
mbar. This will ensure that the