Functional Test of the GRAETZ Dose Rate Alarm Units

Insert the batteries (observe right polarity!). The green battery control LED flashes, indicating the batteries are OK. Otherwise, the batteries have to be replaced.

Check the GM-tube under the influence of ambient background radiation: within 2 minutes approx. 1 count has to be triggered. The red LED flashes and an acoustic alarm sounds. Due to the statistically varying dose rate of ambient background radiation the background counts are spread irregularly, too.

The green battery control LED flashes, indicating the accumulator is OK. Otherwise, the accumulator has to be recharged by means of the recharger unit GRAETZ "462 L".

Check the GM-tube under the influence of ambient background radiation: within 2 minutes approx. 1 count has to be triggered. The red LED flashes and an acoustic alarm sounds. Due to the statistically varying dose rate of ambient background radiation the background counts are spread irregularly, too.

Control the battery contacts in the battery compartment. They have to be non-corrosive and dry.
Visual check of the membrane in the sound transmission aperture. It may not be damaged.

Insert the batteries (observe right polarity!). Turn the switch to "TEST". The instrument must trigger a permanent signal, the LED has to light up. In case of an alarm sound and a flashing LED, the batteries have to be replaced.
Turn the switch to alarm threshold 25 µSv/h. The LED will flash in irregular intervals being a permanent control of the detector, the electronics and the battery voltage.
For additional measurements exceeding ambient background radiation a radioactive test source (e. g. GRAETZ "PS 9") is needed. Generally, ¹³⁷Cs with an activity of 333 kBq is used. The half life of Caesium is 30 years. Remove the test source from the lead storage container and hold it onto the point shaped marking (= position of the GM-tube). When perfectly working, the alarm thresholds 25 µSv/h and 40 µSv/h will trigger an alarm signal. After the control measurements the test source has to be put into the storage container again.

Control the battery contacts in the battery compartment. They have to be non-corrosive and dry.

Use a set-screw to untwist the knob of the "ON"-switch. Remove the spring ring and the cover. Take care that the membrane over the sound transmission aperture is not damaged. After the test cover, spring ring and knob have to be mounted again.

Insert the batteries (observe right polarity!) and set switch to "TEST". The instrument must trigger an alarm signal. The LED must not light up. If the LED lights up and no alarm signal is triggered, the batteries have to be replaced.

For additional tests a radioactive test source (e. g. GRAETZ PS 9) is needed. Generally, ¹³⁷Cs with an activity of 333 kBq is used. The half life of Caesium is 30 years. Remove the test source from the lead storage container and put it onto the ring-like marking situated beside the fixing clip. When the device is perfectly working, the alarm signal will be triggered when reaching the alarm thresholds 25 and 50 µSv/h. After the control measurements the test source has to be put into the storage container again.

Visual control regarding damages on the outside of the instrument. If the housing is damaged, don't put the alarm lamp into operation.

Set the knob for selecting the alarm thresholds to "Test". The green battery control LED must light up at all adjusted alarm thresholds. If the LED does not, the built-in accumulator has to be recharged (recharger unit is supplied together with the GWL 10m).

The functional test of the complete electronics will be started in the switch position "Test", too. When the device is perfectly working, the alarm signal will be triggered in the same way as if an alarm threshold is exceeded.

Functional Test of GRAETZ Dose Rate Alarm Units: GammaSmart, GammaSmart V.Ex, GammaTest C, GAMMATEST 1 and GWL 10m