Model 979 Series Helium Mass Spectrometer Leak Detector
DRAFT 9/15/03
2-15
2.6.1.1 Selecting Internal or External Calibrated Leak for Calibration
Touch the USE INT/EXT LEAK box to switch between selecting whether the 979 performs an
automated calibration to the optional internal calibrated leak or to an external calibrated
leak placed in the test port.
2.6.1.2 Selecting Full or Fast Calibration Routine
Touch the USE FULL/FAST CAL box to switch between FULL CALIBRATION and
FAST CALIBRATION modes.
FULL CALIBRATION
The calibration routine performs a thorough tuning process and a
system gain adjustment (calibration). The full tuning process
involves independently scanning the ion source chamber voltage
and the variable focus voltage, optimizing each value for a maxi-
mum helium signal. Once the tuning process is complete, the sys-
tem gain is adjusted to bring the leak detector into calibration.
FAST CALIBRATION
During fast calibration, the leak detector compares the leak rate
signal with the calibrated leak value and, if the gain adjustment
required to bring the system into calibration is within the allowable
value, the full tuning operation is omitted.
The Calibration routine may be executed without removing the test object or test fixture
from the test port on single mechanical pump configurations, and on dual mechanical
pump configurations set in ROUGH ONLY mode.
NOTE
A test port cap must be in place (isolating the test port) while
performing the Calibration routine on Dual Mechanical Pump
Configurations set in SPLIT FLOW mode.
Summary of Contents for 979 Series
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