Model 979 Series Helium Mass Spectrometer Leak Detector
4-4
DRAFT 9/15/03
4.1 Daily Maintenance
4.1.1 Sensitivity Check
1. Press the READ STANDARD LEAK button.
2. Compare the value displayed on the HOME screen (Section 2.4 “979 Touch Panel
Home Screen” on page 2-8) to the value of the known calibrated leak displayed on the
SYSTEM INFORMATION screen (Section 2.5 “979 System Information Screen” on
page 2-12) or in the CALIBRATED LEAK Set-Up screen (Figure 2-6 on page 2-12).
3. If the values do not match, press the CALIBRATE button to perform an automated
calibration and then repeat step 1. If specification is still not met, Manual Tuning may
be required. See Section 3.1.2 “Manual Spectube Tuning” on page 3-4.
4.2 Recalibrate the Internal Calibrated Leak
Helium calibrated leaks typically degrade at 3 percent per year. The calibrated leak sup-
plied with your 979 must be checked at least once a year to ensure it is at the value stated
on its tag. Failure to check the leak could result in unreliable testing. You can arrange for
testing and re-calibration at a lab of your choice.
Vacuum Technologies provides NIST-traceable calibrated leak testing and verification ser-
vices. You can contact Customer Service at 1-800-8VARIAN to arrange for recalibration.
4.3 Spectrometer Tube Overhaul
Spectrometer tube overhaul consists of removing, cleaning, and re-installing the 979 Spec-
trometer Tube. There are four basic sub-assemblies in the spectrometer tube. Table 4-3 lists
the tools and parts required during overhaul. Removal instructions follow in the order
below.
❑
Thermocouple Button (TC)
❑
Ion Source
❑
Preamplifier
❑
Magnetic Assembly
Summary of Contents for 979 Series
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