Chapter 10 Servicing the Shielding
Mini-Switch LB 471
Chapter 10. Servicing the Shielding
10.1 Checking Shielding and Source
For safety reasons it has to be possible to shut off the active beam
any time. Depending on the operating conditions, the performance
test has to be repeated in adequate intervals
, at the latest every
six months. In case of malfunction or sluggishness of the rotary
shutter the radiological safety officer and the manufacturer have to
be notified immediately.
10.1.1 Testing the Locking Mechanism
This test ensures that the locking mechanism functions correctly,
the shutter is closed and the source completely shielded if the de-
vice handle of cylinder indicates “Closed”. This is very important to
avoid radiation exposure if for whatever reason (e.g. due to a bro-
ken shaft in a point source shielding) “Closed” is indicated alt-
hough the shutter is still open. The radiation protection agency
stipulates that this test be performed in intervals of no more than
6 months. Maybe you will be called upon to present the corre-
sponding documentation on tests carried out in the past and also a
time schedule for upcoming tests.
Notify the process control station that the measuring point is
out of operation during the test.
Read off current count rate on the evaluation unit and write it
down.
Move shutter to the position “Closed” and watch if the dis-
played count rate goes back to zero or a very low background
level (write down data).
Repeat this process 5 times and write down the results every
time.
Make sure that the shutter is freely movable.
Notify the radiological safety officer about the result.
In case of errors or doubt – please contact the service depart-
ment of BERTHOLD TECHNOLOGIES.
Document test including date, device model and serial number,
test results, name of tester. The regulatory authority may re-
quest a copy of the documentation.
In the USA: every six months
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