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03-914647-00:4
Electron Capture Detector
Chemical contaminants may deposit on the components of the detector
assembly as the ECD is operated. In many cases, you can remove
contaminants deposited on the radioactive foil or cell ceramic insulators by
heating.
Refer to the Radiation Safety Manual (P/N 03-913999-00) for detector repair,
radioactive decontamination, foil replacement, and leak-test information.
Note: Although all heated zones on the 3800 have a potential upper
temperature of 450
°
C, Varian recommends that you do not operate the ECD
above 420
°
C. (The radioactive source temperature is less than 400
°
C even
when the detector set temperature is 450
°
C.)
Thermal
Cleaning
With
Carrier
Gas
Use N
2
or Ar/CH
4
as the carrier gas to thermally clean the ECD. Refer to Table 2
on page 39 for flow rates.
1
With carrier gas and makeup gas flowing through the ECD
cell, increase the
DETECTOR TEMP
to 400
°
C.
WA R N IN G :
R A D IATIO N S O U R C E
Do not attempt to chemically clean the source. Submerging the cell in liquid or running
a liquid through the cell will cause radioactivity to migrate, contaminate the exterior of
the cell, and damage the insulators. The cleaning of the radioactive ECD source can by
performed only by an NRC licensee. Cleaning of the ECD source by persons other than
registered NRC licensees is strictly forbidden by law.
C A U T IO N
AVOID FOIL DAMAGE. The carrier gas must be flowing through
the detector cell before setting the
DETECTOR TEMP
above room
temperature. Failure to do so may damage the radioactive foil,
which is not covered by warranty.
