Thermo Scientific RO-20, Руководство по эксплуатации

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2-2 RB-XXX-XXXXXX E RO-20
Löw 08.10.2008
2.3 Operation the Instrument
2.3.1 Checking the Zero Setting
The zero setting of the RO-20 may be checked in any radiation field by selecting the Zero position of
the Function Switch.
If a minor offset from zero exists on the most sensitive range when in a known insignificant field, the
Zero Knob may be used to remove the offset. Zero need not be reset when using the higher ranges.
2.3.2 Minimizing Deflection
When switching from the R/h ranges to the mR/h ranges, transient noise may cause a temporary de-
flection of the meter. The deflection can be minimized by first selecting 500 mR/h, letting the needle
settle, and then switching to the lower ranges.
2.3.3 Ion Chamber
The effective center of the ion chamber is marked by dimples at the front and sides of the RO-20.
Because the ion chamber is vented to the atmosphere, it is sensitive to changes in atmospheric pres-
sure.
Table 2-1 and Table 2-2 give correction factors to be applied if the RO-20 is used at an elevation
other than the elevation at which it was calibrated. Normal atmospheric pressure variations at one lo-
cation are small enough to be ignored.
The chamber output signal is fully temperature compensated. No additional temperature correction is
necessary.
2.3.4 Radiation Overexposure
The RO-20 will not be damaged by exposing it to radiation fields that exceed the full-scale level. Ex-
treme overexposure may cause a minor shift of the Zero position and a small temporary offset on the
most sensitive range. Resetting the Zero Knob may be necessary.
2.3.5 Electronic Circuitry
The chamber bias battery holds the electronic circuitry at 36 volts negative with respect to chassis
potential. Do not short any part of the circuitry to the chassis parts or damage may occur.