Gamma radioactive gas body source absolute detection efficiency calibration device and method

Abstract

The invention discloses a gamma radioactive gas body source absolute detection efficiency calibration device and method. The device comprises a standard face source, a solid small face source, a solid big face source, a gas big face source, a gas body source and a detector. When the height H of the inner cavity of the gas big face source is smaller than a certain specific value Y, the gamma ray absolute detection efficiency deviation of the solid big face source and the gas big face source is smaller than 0.5%, and the detection efficiency of the solid big face source and the detection efficiency of the gas big face source are equivalent within 0.5%. The value Y is taken to prepare the gas big face source, the equivalent detection efficiency of the gas big face source is obtained through the solid big face source with the detection efficiency easy to measure, and the detection efficiency of the gas body source can be obtained through the ratio of the size of the gas big face source to the size of the gas body source. The absolute detection efficiency calibration of any gas body source with an unchanged shape is achieved by ingeniously utilizing quality transition, efficiency equivalency, size transition and other methods. The device and method are convenient and easy to achieve.

Description

technical field [0001] The invention relates to an absolute detection efficiency calibration technology of a gamma ray radioactive source in the application field of nuclear technology, in particular to an absolute detection efficiency calibration device and method of a gamma radioactive gas source. Background technique [0002] In the application field of nuclear technology, the gamma ray gas source is one of the main measurement objects. The HPGe gamma spectrometer is a relative measurement system. The gas source emits gamma rays. The HPGe gamma spectrometer detects the gamma rays and can obtain the characteristic gamma ray full-energy peaks of each radionuclide in the gas source. To accurately measure the activity of the gas source In addition to the nuclear parameters, the calibration value of the absolute detection efficiency of the HPGe gamma spectrometer to detect the relevant gamma rays is also required. Compared with the absolute detection efficiency calibration of...

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Problems solved by technology

This method has high requirements on the precise description of point source and volume source size, source position and detector structure. If the description of volume source structure and size is not accurate, the result of relying on theoretical calculation will bring large deviations.

At home and abroad, software such as LabSOCS or Monte Carlo simulation calculations are also used to realize the passive calibration of gas sources, which saves the process of using standard gas source calibrations and improves work efficiency, but this method has large errors

On the other hand, the literature (Tian Zining et al. Research on Self-absorption Correction Technology of Soil Sample γ Spectrum Analysis, Radiation Protection, 2013) adopts the surface source calibration technology, and conducts experiments at different height h from the crystal to determine the absolute detection efficiency of the surface source as The height change relationship ε(h), the absolute detection efficiency of the gas source is obtained by integral. This method has cumbersome steps and is closely related to factors such as whether the change in the position of the surface source is uniform, the number of selected positions, etc., and is not suitable for high-accuracy measurement.

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