Instruction Manual MIC type EC-912
Revision no.4
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Maintenance and service
Periodic maintenance
Measuring Ionization Chamber (MIC)
The MIC should be cleaned at regular intervals since smoke deposits in the ionization chamber
especially on the radioactive source and the electrode assembly can affect the measuring
characteristics. Smoke deposits on the radioactive source will increase the clean air chamber
resistance while smoke on the electrode assembly may cause leakage currents.
Cleaning of the radioactive source:
The holder for the radioactive source may be unscrewed for cleaning, without dis-mounting other parts
of the MIC, by loosening the locking screw (refer to Fig. A.1.2 in Annex 1) and unscrewing the source
holder. Make sure that the serial number of the source corresponds to the ionization chamber (see
note in Section 5.2).
Fig. 5.1.1
Holder with radioactive source
The following procedure and precautions should be followed for radiation pro-tection reasons:
a)
Never touch the surface of the radioactive source (see Fig. 5.1.1) with your fingers, use
disposable gloves during the work.
b)
Avoid scratching the surface with hard metal tools or the like.
c)
Keep a distance of at least 10 cm from the unscrewed source holder to your eyes.
d)
Do not take the source holder apart.
e)
Clean the surface of the source with paper tissues wetted with alcohol. Do not touch the
tissues with your fingers, use plastic tweezers.