Veeco MS40, Operation And Maintenance Manual, Page: 68 / 169

Vacuum Instrument Corp.
2099 Ninth Avenue
Ronkonkoma, NY 11779
631.737.0900
Vacuum Instrument Corp.
2099 Ninth Avenue
Ronkonkoma, NY 11779
631.737.0900
GAUGES
Test Port Pirani: A gauge that measures pressures from atmosphere to
10
-3
Torr in the test port.
Fore-line Pirani: A gauge that measures pressure at the fore-line side of the
Turbo-molecular pump.
CALIBRATORS
The MS-40 uses three separate testing modes (gross, reverse and direct) in
order to test leak ranges between 10 std cc/sec to 4 x 10
-11
std cc/sec.
Gross Mode: The gross mode calibration covers the range between 10 std
cc/sec to 1 x 10
-5
std cc/sec. The gross valve has a constriction that allows
only a small percentage of the test port gas to enter the high-vacuum
section and reach the mass spectrometer. If helium is detected, the signal
is amplified by the Gross Mode Gain (G1) to correct the measurement.
An external calibrator is required to perform this calibration.
Reverse and Direct Modes: An internal calibrator that emits helium at
a rate between 1 x 10
-8
to 3 x 10
-8
std cc/sec is standard equipment with
every MS-40. External models of differing ranges are also available.
Contact VIC for further information.
ELECTRONICS
The MS-40’s electronics consists of four separate circuit boards (labeled
A through D):
A board - controls the unit’s main processor, logic and sensors
B board - controls the unit’s mass spectrometer voltage supplies
C board - controls the unit’s displays and controls
D board - controls the unit’s handheld remote (optional).
1109-186-00 Rev. C 3-15