BS IEC 60846-2:2015 pdf free download.Radiation protection instrumentation – Ambient and/or directional dose equivalent (rate) meters and/or monitors for beta, X and gamma radiation.
All indicated dose values shall be corrected for non-linear response and, if necessary, for the effect of the influence quantity dose rate.
Where more than one detector is utilized, then these requirements shall apply to each detector.
NOTE The range of the response —29 % to ÷67 % corresponds to the range of the correction factor 1,00 ± 0.40,
The range of the response —37.5 % to 150% corresponds to the range of the correction factor 1,00 ± 0,60.
8.4.3.3 Method of test
The tests with X-rays should be performed using the narrow-spectrum series of radiation qualities of ISO 4037-1, however if very high dose rates are required, the wide-spectrum series or high air kerma rate series may be required.
In order to minimize the number of measurements, in a first step the minimum rated photon energy is determined where both requirements on energy and angular dependence of response are met:
• The energy dependence of response for angles of incidence of a = 0° normalized to its value at ‘37Cs gamma energy, R(E. 0°), is measured and plotted versus the photon energy at the points of the mean energies (fluence weighted) of the used X-ray spectra, E.
• The photon energy where the variation of the relative response falls outside —29 % to +67 % (for 80 keV up to 1,5 MeV) or outside —37,5% to +150 % (for 1,5 MeV up to 7 MeV) is determined.
• For the radiation quality with the mean energy above the lower photon energy thus determined, the relative response is measured for all angles between 0° and 180° at 15° intervals in two perpendicular planes containing the reference direction through the reference point of the dose equivalent (rate) meter.
— If for this radiation quality, all variations of the relative response are between —29 % to +67% (for 80 keV up to 1,5 MeV and 0° to ±60° and 180° to (180°±60°)) and between
—37,5 % to *150 % (for 80 keV up to 1,5 MeV and ±60° to ±120°; however at 90° the variation of the relative response is allowed to be as low as —50 %) and between
—37,5 % to 150 % (for 1,5 MeV up to 7 MeV and 0° to ±60° and 180° to (180°±60°), the procedure shall be repeated with the radiation quality with the next lower mean photon energy.
— Otherwise, the radiation quality with the higher mean energy shall be chosen.
For both radiation qualities used in the test, all measured responses are plotted as a function of photon energy in a lin-log graph. Each two responses belonging together shall be connected by a straight line. The minimum and maximum rated photon energy is obtained by the intersection of the straight line with the specified limits at the highest photon energy.
In a second step, further radiation qualities in the rated range of use shall be chosen to prove that all normalized responses R(E.a) are within its specified limits. One radiation quality is determined by the maximum energy of the rated range of use. If the normalized responses R(E, 0°) determined before have extreme values in the rated range, then the corresponding radiation qualities are further values for these tests concerning the angle of incidence, otherwise at least one quality shall be chosen within the rated range.
In principle, it is desirable that this test be performed at the same dose equivalent (rate) for each radiation quality. In practice, this may not be possible, in which case, the indicated dose equivalent (rate) for each radiation quality shall be corrected for the relative response at the indicated dose equivalent (rate) (see 6.10 of IEC 60846-1:2009).BS IEC 60846-2 pdf download.