SiPM readout-based double-beta plastic scintillator detector

Abstract

The utility model relates to a double-beta plastic scintillator detector based on SiPM readout. The double-beta plastic scintillator detector comprises two hollow plastic scintillators, a SiPM array and a corresponding signal readout circuit, an inflation pipeline, a valve, a reflecting film and a light shielding layer. The two hollow plastic scintillators are stacked away from light; the SiPM array is coupled to the side surface of the hollow plastic scintillator, and the signal-to-noise ratio of the detector is improved by using the SiPM array partition according with the noise reduction technology; the two hollow plastic scintillators pasted with the reflecting films and the light shielding layers are packaged in a stainless steel shell to form a dual-channel beta plastic scintillator detector so as to realize synchronous high-sensitivity measurement of different radioactive gases. According to the utility model, the two hollow plastic scintillators are packaged into the double-beta detector, so that synchronous high-sensitivity measurement of different radioactive gases can be realized. The SiPM is assembled on the side wall of the scintillator, and two oppositely arranged gamma detectors can be adopted for measurement, so that the gamma ray detection efficiency is improved, and the detection sensitivity is further improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to atmospheric radiation environmental monitoring and nuclear facility safe operation monitoring technical field, concretely relates to a kind of double beta plastic scintillator detector based on SiPM reading, for radioactive gas activity measurement. BACKGROUND

[0002] Atmospheric radioactive gas monitoring is an important part of nuclear test ban verification and environmental radioactive radiation monitoring. Because of reactor operation discharge, medical and industrial isotope production and use, nuclear accident leakage, etc., various radioactive gas isotopes are produced and released, resulting in complex sources of atmospheric radioactive gas, multiple complex superposition of nuclide types and concentrations in time and space, i.e. representative existence of single component sample in time and space difference. The development of simultaneous measurement technology of different radioactive gases not only enriches the monitoring means, but also makes up for the problem of insufficient time coverage of single component monitoring.

[0003] The existing inert gas xenon measurement methods and corresponding detectors, as well as measurement methods and detection equipment, have advantages in improving detection sensitivity, but do not involve detectors for simultaneous measurement of multiple radioactive gases.

[0004] Compared with single component radioactive gas nuclide measurement, simultaneous measurement of different radioactive nuclides will produce background interference and reduce detection sensitivity. INVENTION CONTENTS

[0005] The utility model provides a kind of double beta plastic scintillator detector based on SiPM reading, and the technical problems to be solved are: solve the problem that different radioactive nuclides are simultaneously measured and produce background interference, reduce detection sensitivity.

[0006] In order to solve the above technical problems, the utility model provides a kind of double beta plastic scintillator detector based on SiPM reading, characterized by: including two hollow plastic scintillators, SiPM array and gas charging pipeline;Two hollow plastic scintillators are stacked and packaged as a whole in the lightproof state;The outer part of the two hollow plastic scintillators 1 is composed of scintillator material, and the inside of the scintillator is a hollow sealed space;Two hollow plastic scintillators have through holes on one side wall connected with the gas charging pipeline, and the other three side surfaces of the hollow plastic scintillator except the side surface of the gas charging pipeline are coupled with the SiPM array.

[0007] Further, the shape of the scintillator is a cuboid.

[0008] Further, the SiPM array is divided into N units, N is greater than or equal to 2, and the signals of each unit are added separately;When the SiPM of N units has signals at the same time, the signals of N units are added again to output as 1-way signal, which is the output signal of the detector.

[0009] Further, the hollow plastic scintillator has a reflective film covering the rest of the outer region except the region coupled with the SiPM array.

[0010] Further, the two hollow plastic scintillators have a heat insulation layer placed on the side where the gas filling pipeline is introduced.

[0011] Further, the gas filling pipeline is provided with a torsion-proof holder.

[0012] Further, the two light-proof stacked hollow plastic scintillators have carbon fiber windows attached to the end faces except the plane where the SiPM array and the gas filling pipeline are located, and the whole is packaged in a shell.

[0013] Further, the hollow plastic scintillator has a cylindrical cavity in the middle.

[0014] Further, the two hollow plastic scintillators are filled with different gases.

[0015] Further, a PCB circuit board is arranged above the side where the gas filling pipeline is located.

[0016] Beneficial effects: The utility model discloses a detector design and multiple coincidence / anti-coincidence technical means, eliminate cosmic rays and radioactive gas mutual interference, can realize different radioactive gas nucleuses simultaneous measurement, can improve the sensitivity of radioactive gas nucleuses detection greatly, and obtain more abundant monitoring information.

[0017] The hollow plastic scintillator is coupled with the SiPM array on the side, the SiPM array partition coincidence noise reduction technology is used to improve the signal-to-noise ratio of the detector, two hollow plastic scintillators with reflective film and light-proof layer are packaged into a stainless steel shell to form a double-channel beta detector, and synchronous high-sensitivity measurement of different radioactive gases is realized.

[0018] 1. The utility model discloses two hollow plastic scintillators are packaged into a double beta detector, and synchronous high-sensitivity measurement of different radioactive gases can be realized.

[0019] 2. The SiPM is assembled on the side wall of the scintillator, two opposite gamma detectors can be used for measurement, the gamma ray detection efficiency is improved, and the detection sensitivity is improved. DETAILED DESCRIPTION

[0020] Figure 1 It is a double beta plastic scintillator detector structure diagram based on SiPM reading out;

[0021] Figure 2 It is a double beta plastic scintillator detector assembly diagram based on SiPM reading out;

[0022] Figure 3 It is a double beta plastic scintillator detector based on SiPM reading out;

[0023] Figure 4 The schematic diagram of a beta-gamma coincidence system composed of a double-beta plastic scintillator detector and HPGe detectors;

[0024] Figure 5 The 133 The two-dimensional coincidence spectrum of Xe 81keV gamma rays and beta rays with a maximum energy of 346keV;

[0025] Figure 6 The 85 The two-dimensional coincidence spectrum of Kr 514keV gamma rays and beta rays with a maximum energy of 178keV;

[0026] Wherein: 1 - hollow plastic scintillator; 2 - SiPM array (silicon photomultiplier) ; 3 - air charging pipeline; 4 - PCB circuit board; 5 - thermal insulation layer; 6 - anti-twist holder; 7 - signal interface; 8 - shell; 9 - carbon fiber window; 10 - power interface; 11 - double-beta plastic scintillator detector; 12 - two sets of HPGe detectors; 13 - two preamplifiers; 14 - two main amplifiers; 15 - two high voltages; 16 - OR logic circuit; 17 - anti-cosmic ray detector output signal; 18 - digital coincidence instrument; 19 - computer; 20 - liquid nitrogen recondensation refrigeration device; 21 - valve. DETAILED DESCRIPTION

[0027] In order to make the purpose, content and advantages of the utility model more clearly, the specific embodiment of the utility model is described in further detail below.

[0028] The utility model discloses a double-beta plastic scintillator detector based on SiPM reading, including two hollow plastic scintillators 1, SiPM array 2, air charging pipeline 3, valve 21, reflective film and light -proof layer, two hollow plastic scintillators light -proof and place in stacks.

[0029] The two hollow plastic scintillators 1 are all composed of scintillator material outside, and the scintillator shape is cuboid, and the inside is hollow sealed space.

[0030] Two hollow plastic scintillators are connected with air charging pipeline according to need and leave through -hole in a side wall.

[0031] The hollow plastic scintillator is coupled with SiPM array on the remaining three side surfaces except the side surface where the air charging pipeline is located, and the SiPM array partition coincidence noise reduction technology is utilized to improve the signal-to-noise ratio of the detector.

[0032] The PCB circuit board is provided with a signal reading circuit, which is used for processing and outputting the SiPM array signals of the two hollow plastic scintillators, and the SiPM array is divided into N units (N is greater than or equal to 2), and the signals of each unit are added separately; when the SiPMs of the N units have signals at the same time, the signals of the N units are added again to output as a 1-way signal as the output signal of the detector.

[0033] Except the region coupled with the SiPM array, the remaining external region of the hollow plastic scintillator is covered with a reflective film.

[0034] Heat insulation layers are arranged on the sides of the two hollow plastic scintillators leading the inflation pipeline to reduce the temperature change caused by the heat of the circuit board; a twist-preventing clamp is arranged at the inflation pipeline to avoid the peeling and air leakage caused by the twist of the inflation pipeline.

[0035] The two hollow plastic scintillators, the SiPM array, the corresponding signal reading circuit and the reflective film are all encapsulated in a light-proof layer to avoid light, and the light-proof layer has a through hole through which the inflation pipeline passes, and the inflation pipeline is connected with a valve.

[0036] The two light-proof hollow plastic scintillators are stacked, and carbon fiber windows are attached to the remaining two surfaces except the plane where the SiPM array and the inflation pipeline are located; power supply, signal and inflation interfaces are left after encapsulation.

[0037] In the utility model, the hollow plastic scintillator is a cuboid with the size of 65mm*65mm*14mm, and a cylindrical cavity with the size of Φ60mm*10mm is arranged in the middle of the interior, which is used for filling radioactive gas samples; except the side where the inflation pipeline is located, the remaining three sides of the scintillator are coupled with 30 (2*10*3) SiPM arrays 2 with the size of 6mm*6mm; the heat insulation layer 5 is used for preventing the change of the SiPM amplification caused by the heat of the PCB circuit board 4 and other electronic devices; the twist-preventing clamp 6 is used for preventing the peeling and air leakage of the detector caused by the rotation of the stainless steel pipe; the inflation pipeline 3 is adhered to the scintillator 1 with epoxy glue to ensure that the gas filled in the cavity of the scintillator does not leak; the carbon fiber windows 9 are arranged on the two end surfaces of the double-beta plastic scintillator detector to reduce the absorption of gamma rays.

[0038] The 85 Kr and 133 Xe are filled into the two hollow plastic scintillators 21-1 and 21-2 of the double-beta plastic scintillator detector based on SiPM reading, and a beta-gamma coincidence system is established by using the double-beta plastic scintillator detector based on SiPM reading and the HPGe detector of the utility model (as shown in Figure 4), wherein the double beta plastic scintillator detector 11 is placed between two sets of HPGe detectors 12-1 and 12-2, signals of preamplifiers 13-1 and 13-2 of the two sets of HPGe detectors are amplified by main amplifiers 14-1 and 14-2 respectively and then input into a digital coincidence unit 18 through an OR logic circuit 16; two high-voltage modules 15-1 and 15-2 are used to provide high voltage for the two sets of HPGe detectors respectively; and the output signal of the double beta plastic scintillator detector 11 and the output of the anti-cosmic ray detector 7 are both connected to the digital coincidence unit 18.

[0039] Two liquid nitrogen recondensation refrigeration devices 20-1 and 20-2 provide low-temperature working environments for the two sets of HPGe detectors respectively; and the double beta plastic scintillator detector and the two sets of HPGe detectors are both arranged in a lead shielding room 22 to shield environmental radioactive background.

[0040] By using 85 the coincidence relationship between the maximum energy 173.1 keV beta ray and the 514 keV gamma ray of Kr and 133 the coincidence relationship between the maximum energy 346 keV beta ray and the 81 keV gamma ray of Xe, the two kinds of gas are respectively filled into two hollow plastic scintillators of the double beta plastic scintillator detector, 133 Xe is measured by coincidence of the output signal I of the double beta plastic scintillator detector and the OR-added HPGe signal, and anticoincidence of the output signal II of the double beta plastic scintillator detector, so as to eliminate 85 the influence of Kr bremsstrahlung on 133 Xe measurement; 85 Kr is measured by coincidence of the output signal II of the double beta plastic scintillator detector and the OR-added HPGe signal, and anticoincidence of the output signal I of the double beta plastic scintillator detector, so as to reduce 133 the influence of Xe on 85 Kr measurement; and the anti-cosmic ray device can further reduce the influence of cosmic rays, thereby improving the detection sensitivity. Figures 5-6 The double beta plastic scintillator detector is used for measuring 85 Kr and 133 Xe gas samples, and the beta-gamma two-dimensional coincidence spectrum of the gas sample is obtained.

[0041] The above only describes preferred embodiments of the present application, and it should be noted that, for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A double-beta plastic scintillator detector based on SiPM readout, characterized by: It comprises two hollow plastic scintillators, a SiPM array and a gas filling pipeline; the two hollow plastic scintillators are light-proof and stacked together; the two hollow plastic scintillators are composed of scintillator materials on the outside and hollow sealed spaces on the inside; the two hollow plastic scintillators are connected with the gas filling pipeline through a through hole on a certain side wall; the hollow plastic scintillators are coupled with the SiPM array on the other three side walls except the side wall where the gas filling pipeline is located.

2. A double-beta plastic scintillator detector based on SiPM readout according to claim 1, characterized in that: The scintillator is in the shape of a cuboid.

3. A double-beta plastic scintillator detector based on SiPM readout according to claim 1, characterized in that: The SiPM array is divided into N units, N is greater than or equal to 2, and the signals of each unit are added separately; when the N units of SiPM have signals at the same time, the signals of the N units are added again to output as a one-way signal as the output signal of the detector.

4. The dual-beta plastic scintillator detector based on SiPM readout according to claim 1, characterized in that: The hollow plastic scintillator is covered with a reflective film in the remaining external area except the area coupled with the SiPM array.

5. A double-beta plastic scintillator detector based on SiPM readout according to claim 1, characterized in that: The side wall of the two hollow plastic scintillators where the gas filling pipeline is located is provided with a heat insulation layer.

6. A dual-beta plastic scintillator detector based on SiPM readout according to claim 1, characterized in that: The gas filling pipeline is provided with an anti-twist holder.

7. A dual-beta plastic scintillator detector based on SiPM readout according to claim 1, characterized in that: The two light-proof and stacked hollow plastic scintillators are provided with carbon fiber windows on the two end faces except the plane where the SiPM array and the gas filling pipeline are located; the whole is packaged in an outer shell.

8. A dual-beta plastic scintillator detector based on SiPM readout according to claim 1, characterized in that: The hollow plastic scintillator is internally provided with a cylindrical cavity.

9. A dual-beta plastic scintillator detector based on SiPM readout according to claim 1, characterized in that: Different gases are filled into the two hollow plastic scintillators.

10. A double-beta plastic scintillator detector based on SiPM readout according to claim 1, characterized in that: A PCB circuit board is arranged above the side wall where the gas filling pipeline is located, which is used for processing and outputting the SiPM array signal of the two hollow plastic scintillators.

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