This International Standard establishes methods for performance testing, calibration and usage of Nal (TI) detector systems for the measurement of gamma-ray energies and emission rates of radionuclides and the assay for radioactivity.
This standard provides a standardized basis for the calibration and usage of sodium iodide detector systems for the measurement of gamma-ray emission rates of radionuclides. Typical applications include radionuclide identification and assay in various industrial, environmental, and medical applications. A thallium activated sodium iodide detector system consists of three major components: a scintillating medium that produces photons of light when ionizing radiation interacts with it; one or more photomultipliers or photodiodes, optically coupled to the scintillator, which converts the light photons to an amplified electrical pulse or pulses; and associated electronic instrumentation which powers the photomultiplier and processes the output signal.
Both energy calibration and efficiency calibration are covered. The following three techniques are considered:
a) total spectrum counting (see 4.1) which employs a system that counts all pulses above a low-energy threshold (see 6.1, 6.2 and 6.3);
b) single-channel analyzer counting (see 4.2) which employs a system with a counting window which establishes upper and lower energy boundaries (see 6.1, 6.2, and 6.3);
c) multichannel analyzer counting (see 4.3) which employs a system in which multiple counting windows are utilized. This technique allows measurements for which the continuum under the full-energy peak may be subtracted without introducing unacceptable error. In case of overlapping peaks in the spectrum, it is realized that a multichannel analyzer (MCA) with access to a spectrum-stripping program is necessary. This case is not covered by this standard.
IEC 61453:1997 history
2007IEC 61453:2007 Nuclear instrumentation - Scintillation gamma ray detector systems for the assay of radionuclides - Calibration and routine tests
1997IEC 61453:1997 Nuclear instrumentation - Thallium activated sodium iodide detector systems for assay of radionuclides - Calibration and usage