INFICON Front Load Single Sensor - Manual (Page 70)

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Front Load Single and Dual Sensors Operating Manual
4.3.2 Cleaning the Crystal Holder
In dielectric coating applications, the crystal seating surface of the crystal holder
may require periodic cleaning. Since most dielectrics are insulators, any material
buildup on this surface from an evaporation process can cause a poor electrical
contact between the crystal and the crystal holder. Material buildup will also cause
a reduction in thermal transfer from the crystal to the sensor body. A poor electrical
contact or poor thermal transfer will result in noisy operation and early crystal
failure.
Cleaning may be accomplished by following three steps:
1 Gently buffing the crystal seating surface in the crystal holder with a white,
#7445 Scotch-Brite™ cleaning pad (see
Figure 4-5 ).
2 Washing the crystal seating surface in the crystal holder in an ultrasonic bath
in soap solution.
3 Thorough rinsing of the crystal seating surface in the crystal holder with
deionized water and drying, or by ultrasonic cleaning and deionized water
rinsing only.
NOTE: The crystal holder seating surface is machined to a very fine finish
(16 micro inches rms). This high quality finish is essential to provide good
electrical and thermal contact with the crystal.
CAUTION
Applying excessive force during cleaning or using overly
abrasive cleaning materials may damage this finish and
reduce sensor performance.
Figure 4-5 Crystal holder cleaning
Clean or polish
these surfaces.
Remove all oxides.
Do not scratch.