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Date: 22 October 2021
Doserate instrument tests
Tests are carried out in accordance with the industry Good Practice Guide, GPG14, “The examination, testing & calibration of portable radiation protection instruments”. Any deviations from type test values (where available) and any significant change in an instrument’s response is reported clearly on the certificate
Instruments' responses to high doserates and alarm settings
It is necessary to test instruments up to the maximum doserate they are likely to encounter in practice. This may be in excess of the maximum indication on the display.
One of the tests carried out is to confirm that the display indicates off-scale for approximately 30 seconds during the high doserate test.
Alarm levels (visual/audible) are checked when appropriate.
A single Cs-137 (662keV) source is used to provide a full range of traceable air kerma rates to confirm:
- the instrument has a linear response over the full scale
- the response of the monitor to high-energy radiations
An Am-241 source (60keV photon) is used to confirm the energy response of the instrument does not vary significantly from the type test data. Faults in the construction of a detector can be identified using this test.
This test is carried out on any new instrument or an instrument that has had a significant repair since a previous calibration to confirm the correct assembly of a detector. For example, energy compensation filters may be missing from a compensated Geiger-Muller detector.
We appreciate that users of electronic personal dosemeters, that do not come under the legislation of radiation protection instrumentation, may also require an annual test. A range of tests carried out in accordance with Good Practice Guide 113 “The examination and testing of electronic personal dosemeters” is available for these types of dosemeters but we also offer a functional check whereby the dosemeter undergoes a limited range of tests for a reduced price. Full details are available on request.
For further information, please contact:
- General enquiries: Tracie Such
- Technical enquiries: Joanne Johnson, John Lewis
63 Melchett Road
Kings Norton Business Centre
Telephone: 0121 371 7000