Device and method for evaluating relative light output performance of large-size scintillation crystal

Abstract

The invention belongs to the field of nuclear radiation detection, and particularly relates to a device and method for evaluating the relative light output performance of a large-size scintillation crystal, and the device comprises a flexible clamp, a collimation radioactive source, a light limiting valve, a photomultiplier tube, a shielding container, a shading cover, a high-voltage power supply, an energy disperse spectroscopy, and a computer. The collimation radioactive source is placed right above the flexible clamp; the flexible clamp is placed right above the photomultiplier tube; the light limiting valve covers one surface, in contact with the flexible clamp, of the photomultiplier; during a test period, the light source is placed in the shading container and is sealed by a shading cover; a wire outlet hole is formed in the bottom of the shading container, and a connecting wire of the photomultiplier penetrates through the wire outlet hole to be connected with the high-voltage power supply and the multiple energy dispersive spectrometers; and the energy disperse spectroscopy is connected with the computer. According to the invention, the problems in measurement of the large-size scintillation crystal are solved, and the measurement accuracy is ensured.

Description

Technical Field

[0001] The present invention belongs to the field of nuclear radiation detection, and in particular relates to a device and method for evaluating the relative light output performance of large-size scintillation crystals. Background Art

[0002] The light output performance of scintillation crystals is a key indicator of their detection efficiency, directly impacting the signal-to-noise ratio, energy resolution, and sensitivity of radiation detectors. High light output enhances the ability to extract weak signals and improves detection accuracy, making it suitable for medical imaging (such as PET), high-energy physics experiments, nuclear radiation monitoring, and security inspections. The relative light output method is often used in scintillation crystal light output testing. This method is simple, quick, and suitable for testing large quantities of crystals.

[0003] However, testing the relative light output of large scintillator crystals presents several challenges: 1) It is difficult to find photomultiplier tubes that match the size of the crystals. 2) Crystal sizes can vary. For example, after a crystal ingot is cut into uniformly thick wafers, factory testing is required. In this case, the wafers have consistent thickness but varying diameters. How can we eliminate discrepancies in test results caused by varying light reflections from the crystal edges due to varying sizes? Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a device and method for evaluating the relative light output performance of large-sized scintillation crystals.

[0005] In one aspect, the present invention provides an apparatus for evaluating the relative light output performance of large-scale scintillation crystals, comprising: a flexible fixture, a collimated radiation source, a light-limiting valve, a photomultiplier tube, a shielding container, a light-shielding cover, a high-voltage power supply, an energy spectrometer, and a computer;

[0006] The flexible fixture is composed of a highly elastic material sleeve and a rigid plug; a large-sized crystal is placed from the rear end of the flexible fixture, and the rigid plug is used to push the crystal to the bottom and avoid light;

[0007] The collimated radiation source is placed directly above the flexible fixture when in use;

[0008] The flexible clamp is placed directly above the photomultiplier tube when in use;

[0009] The light limiting valve is a black film with a hole in the middle. The side of the photomultiplier tube that contacts the flexible clamp is covered with the light limiting valve, which is used to limit the geometric range of light entering;

[0010] The flexible fixture, collimated radiation source, light limiting valve, and photomultiplier tube are placed inside the light-shielding container and sealed by a light-shielding cover;

[0011] The bottom of the light-shielding container is provided with a wire outlet hole, and the connecting wire of the photomultiplier tube passes through the wire outlet hole to be connected to the high-voltage power supply and the multi-channel spectrometer;

[0012] The energy spectrometer is connected to the computer.

[0013] In another aspect, the present invention provides a method for evaluating the relative light output performance of a large-scale scintillation crystal, comprising:

[0014] S1: Insert the scintillation crystal from the rear end of the flexible sleeve and use a rigid plug to push the crystal to the bottom of the fixture to wrap it tightly;

[0015] S2: Place the light-limiting valve at the center of the photomultiplier tube to ensure that only the center can receive light.

[0016] S3: Connect the high voltage power supply, multi-channel spectrometer, and computer;

[0017] S4: Place the collimated radiation source at the center of the flexible fixture and cover it with a light shield;

[0018] S5: Turn on the voltage and start measuring. Find the full energy peak position and compare it with the full energy peak position of the standard block to obtain the relative light output.

[0019] Beneficial effects of the present invention:

[0020] The present invention designs a flexible fixture that effectively reduces side photon reflections of large-sized crystals and mitigates the impact of crystal size on light output performance. Through the fixture design, the light output performance of large-sized crystals of different sizes can be measured under the same measurement conditions, and the light output performance of large-sized crystals can be evaluated under conditions of different crystal sizes.

[0021] The present invention reduces photon reflection by adding an ultra-black coating inside the fixture, thereby reducing reflection differences caused by different crystal sizes. A light limiter is added above the photomultiplier tube to reduce differences in fluorescence caused by radiation excitation at different positions. This fully considers the impact of crystal edge reflection caused by size differences when testing crystals of different sizes.

[0022] The present invention comprehensively applies radiology, materials, mechanics and other interdisciplinary technologies to solve the problems faced by large-sized scintillation crystals in measurement and ensure the accuracy of measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 is a cross-sectional view of the flexible clamp and crystal of the present invention;

[0025] Figure 3This is a diagram of the flexible clamp and crystal assembly of the present invention. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] A device and method for testing the relative light output of large-scale crystals, such as Figure 1 As shown, the device is mainly divided into the following parts: 1-high voltage power supply, 2-shielding container, 3-flexible clamp and crystal, 4-light limiting valve, 5-photomultiplier tube, 6-light shield, 7-multi-channel spectrometer, 8-computer, 9-collimated radiation source, 10-crystal cake, 11-flexible sleeve, 12-rigid plug;

[0028] like Figure 2 As shown, the flexible fixture is composed of a highly elastic material sleeve (such as liquid silicone) and a rigid plug. The inside of the sleeve is coated with an ultra-black coating that can effectively absorb photons and prevent photons from reflecting at the edges.

[0029] like Figure 3 As shown, the crystal is placed from the rear end of the flexible fixture, and a rigid plug is used to push the crystal to the bottom and protect it from light.

[0030] The collimated radiation source is wrapped with lead blocks, and the internal radiation source is 137 Cs, which can provide a vertical downward gamma ray, is placed just above the flexible fixture when in use.

[0031] The light limiting valve is a black film with a hole in the middle, which covers the photomultiplier tube and is used to limit the geometric range of light entering.

[0032] The light-shielding container and light-shielding cover are made of stainless steel and are used to protect against light.

[0033] The high-voltage power supply is used to provide high voltage. The photomultiplier tube converts the optical signal into an electrical signal. The multi-channel spectrometer is used to process the electrical signal and cooperate with the host computer to form an energy spectrum.

[0034] The light output test method for large-size scintillator crystals is as follows:

[0035] Insert the scintillation crystal from the rear end of the flexible sleeve and use the rigid plug to push the crystal to the bottom of the fixture to make it tightly packed.

[0036] Place the light-limiting valve in the center of the photomultiplier tube to ensure that only the center can receive light.

[0037] Connect the high voltage power supply, multi-channel energy spectrometer, and computer.

[0038] Place the collimated radiation source in the center of the flexible fixture and cover it with a light shield.

[0039] Turn on the voltage and start measuring. Find the full energy peak position and compare it with the full energy peak position of the standard block to get the relative light output.

[0040] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A device for evaluating the relative light output performance of large-scale scintillation crystals, characterized in that: Including; flexible fixture, collimated radiation source, light limiting valve, photomultiplier tube, shielding container, light shielding cover, high voltage power supply, energy spectrometer, computer; The flexible fixture is composed of a highly elastic material sleeve and a rigid plug; a large-sized crystal is placed from the rear end of the flexible fixture, and the rigid plug is used to push the crystal to the bottom and protect it from light; The collimated radiation source is placed directly above the flexible fixture when in use; The flexible clamp is placed directly above the photomultiplier tube when in use; The light limiting valve is a black film with a hole in the middle. The side of the photomultiplier tube that contacts the flexible clamp is covered with the light limiting valve, which is used to limit the geometric range of light entering; The flexible fixture, collimated radiation source, light limiting valve, and photomultiplier tube are placed inside the light-shielding container and sealed by a light-shielding cover; The bottom of the light-shielding container is provided with a wire outlet hole, and the connecting wire of the photomultiplier tube passes through the wire outlet hole to be connected to the high-voltage power supply and the multi-channel spectrometer; The energy spectrometer is connected to the computer.

2. The device for evaluating the relative light output performance of large-scale scintillation crystals according to claim 1, characterized in that: The interior of the sleeve is coated with an ultra-black coating that can effectively absorb photons and prevent them from reflecting at the edges.

3. The device for evaluating the relative light output performance of large-scale scintillation crystals according to claim 1, characterized in that: The collimated radiation source is wrapped with a lead block on the outside, and the internal radiation source is 137 Cs, which provides a vertically downward gamma ray.

4. The device for evaluating the relative light output performance of large-scale scintillation crystals according to claim 1, characterized in that: The light-shielding container and light-shielding cover are made of stainless steel and are used to protect against light.

5. The device for evaluating the relative light output performance of large-sized scintillation crystals according to claim 1, characterized in that: The photomultiplier tube converts the optical signal into an electrical signal, and the multi-channel energy spectrometer is used to process the electrical signal and form an energy spectrum diagram in cooperation with the host computer.

6. A method for evaluating the relative light output performance of large-scale scintillation crystals, the method being implemented based on the apparatus of claims 1-5, characterized in that: include: S1: Insert the scintillation crystal from the rear end of the flexible sleeve and use a rigid plug to push the crystal to the bottom of the fixture to wrap it tightly; S2: Place the light-limiting valve at the center of the photomultiplier tube to ensure that only the center can receive light. S3: Connect the high voltage power supply, multi-channel spectrometer, and computer; S4: Place the collimated radiation source at the center of the flexible fixture and cover it with a light shield. S5: Turn on the voltage and start measuring. Find the full energy peak position and compare it with the full energy peak position of the standard block to obtain the relative light output.

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