4pi multi-wire proportional chamber for 4pi beta-gamma coincidence measurement

Abstract

The invention discloses a 4pi multi-wire proportional chamber for 4pi beta gamma coincidence measurement. The 4pi multi-wire proportional chamber comprises a frame, an upper cover plate, a lower coverplate, a supporting plate and anode wires; the upper cover plate covers the top surface of the frame, and the lower cover plate covers the bottom surface of the frame; a guide groove matched with thesupporting plate is formed in the side surface of the frame; the supporting plate is used for placing a radioactive source, and the supporting plate penetrates through the guide groove and is mountedin the frame; the interior of the frame is divided into an upper chamber and a lower chamber by the supporting plate; the anode wires are arranged in the upper chamber and the lower chamber; and thetwo ends of the anode wires are fixed on the frame. According to the 4pi multi-wire proportional chamber for 4pi beta gamma coincidence measurement, the source preparation difficulty of an absolute radioactive activity measurement method for 4pi beta gamma coincidence measurement is reduced, and the 4pi beta gamma coincidence measurement method can be used for directly measuring the radioactive activity of a large-area radioactive source similar to a plane source.

Description

technical field [0001] The invention relates to the technical field of ionizing radiation measurement, in particular to a 4π multi-wire proportional chamber for 4πβ-γ coincidence measurement. Background technique [0002] The 4πβ-γ coincidence measurement method is an absolute measurement method for measuring radioactivity. Because this method adopts coincidence technology, it has extremely high accuracy for most β-γ nuclides, so the main metrology institutions (National Metrology Institutes, NIMs) in each country have established corresponding 4πβ-γ coincidence measurement devices, And use it as a reference device for radioactivity measurement in a country. The 4πβ-γ coincidence measurement device contains two types of detectors, respectively detecting two types of radioactive particles emitted during the same decay process. Among them, the detector used to detect β particles is called a β detector, and the detector used to detect γ particles is called a γ detector. [0...

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Problems solved by technology

The 4π proportional counter adopts the arrangement of a single anode wire, and its electric field distribution is divergent. Therefore, for a radioactive source with a large area, the detection efficiency of radioactive substances at different positions in the source is not consistent, which affects the measurement results.

[0004] In order to make the influence of the area of ​​the radioactive source negligible, it is usually necessary to control the source diameter of the radioactive source within 3mm when preparing the radioactive source to be tested, so it has high technical difficulty

In addition, for the planar sources used in nuclear technology applications such as medical treatment, isotope production, environmental monitoring, and industrial control, the source diameter is usually greater than 10 mm, so the 4πβ-γ conformance measurement method cannot be used without destroying the radioactive source. Direct measurement of its radioactivity

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