A high signal-to-noise ratio vacuum Compton detector sensitivity calibration system

Abstract

The application provides a high signal-to-noise ratio vacuum Compton detector sensitivity calibration system, and mainly solves the technical problem that the sensitivity measurement uncertainty of the sensitivity calibration system is high due to the low signal-to-noise ratio of the vacuum Compton detector in the existing sensitivity calibration system. The system comprises a connector and a compensation module; the compensation module comprises a compensation shell, a compensation combined core arranged in the compensation shell, an insulating block arranged on the side of the compensation combined core, and a compensation signal head arranged on the outer side of the compensation shell; the input end of the connector is connected with the other end of the signal line, the first output end of the connector is connected with the input end of the galvanometer, the second output end is connected with one end of the compensation signal head, the compensation signal head is arranged on the compensation shell, and the other end is connected with the compensation combined core through a lead wire; the compensation combined core comprises a plurality of compensation cores connected in sequence; one of the compensation cores close to the compensation signal head is connected with the other end of the compensation signal head through a lead wire.

Description

Technical Field

[0001] This invention relates to a detector sensitivity calibration system, specifically a high signal-to-noise ratio vacuum Compton detector sensitivity calibration system. Background Technology

[0002] The Vacuum Compton Detector (VCD) is a radiation detector designed based on the Compton scattering effect of gamma rays with materials. It has advantages such as ultra-low sensitivity, fast time response, and wide pulse linear range, and has been widely used in the measurement of high-intensity pulsed gamma rays.

[0003] In pulsed radiation measurement, sensitivity is a key characteristic of pulsed radiation detectors, directly reflecting the intensity information of pulsed rays. Therefore, reducing the uncertainty of sensitivity measurement plays an important role in improving the accuracy and reliability of pulsed gamma ray intensity measurement. The factors affecting the uncertainty of sensitivity measurement mainly include the uncertainty of ray dose rate measurement, the uncertainty of detector position measurement, and the uncertainty of detector output current measurement. Among these, the uncertainty of detector output current measurement is the most significant, and the uncertainty of detector output current measurement mainly depends on the signal-to-noise ratio of detector output current.

[0004] The existing sensitivity calibration system suffers from high sensitivity measurement uncertainty due to the low signal-to-noise ratio of the vacuum Compton detector. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problem that the low signal-to-noise ratio of the vacuum Compton detector in existing sensitivity calibration systems leads to high uncertainty in sensitivity measurement, and to provide a high signal-to-noise ratio vacuum Compton detector sensitivity calibration system.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A high signal-to-noise ratio vacuum Compton detector sensitivity calibration system, wherein the vacuum Compton detector to be calibrated includes an emitter, two end caps respectively connected to the two ends of the emitter, a signal lead connected to the emitter at one end, and a detector signal head connected to the other end of the signal lead;

[0008] Includes a signal line and a galvanometer; one end of the signal line is connected to the detector signal head;

[0009] Its special feature is:

[0010] The connecting head and the compensation module are further included; the compensation module includes a compensation shell, a compensation combined core arranged in the compensation shell, an insulating block arranged on the circumferential side of the compensation combined core, and a compensation signal head arranged on the outer side of the compensation shell;

[0011] The input end of the connecting head is connected with the other end of the signal line, the first output end of the connecting head is connected with the input end of the ammeter, the second output end is connected with one end of the compensation signal head, the compensation signal head is arranged on the compensation shell, and the other end is connected with the compensation combined core through a lead wire;

[0012] The compensation combined core includes a plurality of compensation cores connected in sequence; one compensation core close to the compensation signal head is connected with the other end of the compensation signal head through the lead wire;

[0013] Definition: the total number of the plurality of compensation cores from one end of the connecting lead wire to the other end away from the connecting lead wire is N, 2≤N≤5, and respectively N1, N2, …, NN; definition: from the end cap in the vacuum Compton detector to be calibrated, sequentially through the emitter, the signal lead-out wire, the detector signal head to the signal line, each section of the same continuous conductive material is a conductive section, and the total number of the conductive sections is M, 2≤M≤5, and respectively M1, M2, …, MM;

[0014] Then N=M, and the conductive material of the compensation cores N1, N2, …, NN is the same as that of the conductive sections M1, M2, …, MM, and is used for compensating the contact potential difference introduced by different core materials.

[0015] Further, an installation cavity is arranged in the insulating block, and the compensation combined core is arranged in the installation cavity, and the lead wire is connected with the compensation core through the insulating block;

[0016] The outer circumferential side of the insulating block is matched with the inner wall of the compensation shell, and is used for supporting the compensation combined core.

[0017] Further, the material of the insulating block is polyethylene.

[0018] Further, the plurality of compensation cores are coaxially arranged and have the same structure.

[0019] Further, the wire core material of the lead wire, the conductor material of the connecting head and the conductive material of the internal circuit board of the ammeter are the same, and are all aluminum materials, and the core material of the input end of the ammeter and the core material of the signal line are the same;

[0020] N=M=3, and respectively N1, N2, N3 and M1, M2, M3; and the conductive material of the compensation cores N1, N2, N3 is the same as that of the conductive sections M1, M2, M3.

[0021] Further, the to-be-calibrated vacuum Compton detector further comprises a detector shell, two insulating ceramic columns, an incident window and an exit window oppositely arranged on two side walls of the detector shell, and a detector signal head arranged outside the detector shell.

[0022] The emitter and the end cap are arranged inside the detector shell, the axial direction of the emitter is perpendicular to the opening direction of the incident window, one end of each of the two insulating ceramic columns is connected with the two end caps respectively, and the other end of each of the two insulating ceramic columns is connected with the inner wall of the detector shell.

[0023] One end of the detector signal head is connected with the emitter through a signal lead-out wire, and the other end of the detector signal head is connected with a signal line; the material of the signal lead-out wire and the material of the detector signal head are the same as the material of the signal line.

[0024] Further, the material of the end cap is stainless steel, the material of the emitter is iron, and the material of the signal line is copper.

[0025] Further, the material of the detector shell is stainless steel; the thickness of the emitter is 2mm, and the diameter of the emitter is 50mm; and the vacuum degree inside the detector shell is lower than 0.01Pa.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] 1. The present application can compensate the contact potential difference introduced by different materials along the current transmission path in the sensitivity calibration system by designing the compensation combination core with multiple compensation cores, reduce the dark current introduced by the metal contact potential difference, and thus improve the signal-to-noise ratio of the vacuum Compton detector and reduce the measurement uncertainty of the sensitivity of the detector.

[0028] 2. The present application only needs to adaptively adjust the core material through which the current flows in the sensitivity calibration system with different structures, so as to achieve the purpose of suppressing the dark current, and has relatively wide applicability. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a structural schematic view of a high signal-to-noise ratio vacuum Compton detector sensitivity calibration system of the present application;

[0030] Figure 2 is a structural schematic view of a vacuum Compton detector in an embodiment of a high signal-to-noise ratio vacuum Compton detector sensitivity calibration system of the present application;

[0031] Figure 3 is a structural schematic view of a compensation module in an embodiment of a high signal-to-noise ratio vacuum Compton detector sensitivity calibration system of the present application;

[0032] Figure 4It is the dark current waveform chart when the emitter is iron material in a high signal-to-noise ratio vacuum Compton detector sensitivity calibration system embodiment of the present application;

[0033] Figure 5 It is the dark current waveform chart when the emitter is aluminum material in a high signal-to-noise ratio vacuum Compton detector sensitivity calibration system embodiment of the present application.

[0034] In the figure, 1 is a vacuum Compton detector, 11 is an emitter, 12 is an end cap, 13 is a detector shell, 14 is a detector signal head, 15 is an insulating ceramic column, 2 is a signal line, 3 is a current meter, 4 is a connecting head, 5 is a compensation module, 51 is a compensation shell, 52 is a compensation core, 53 is an insulating block, 54 is a compensation signal head, 6 is a lead wire, and 7 is a signal lead-out wire. DETAILED DESCRIPTION

[0035] In order to make the purpose, advantages and characteristics of the present application clearer, a high signal-to-noise ratio vacuum Compton detector sensitivity calibration system of the present application is further described in detail below in combination with the drawings and specific embodiments. The advantages and characteristics of the present application will be clearer according to the following specific embodiments. It should be noted that: the drawings are all very simplified and use non-precise proportions, and are only used to facilitate and clarify the purpose of assisting in the description of the embodiments of the present application; secondly, the structures shown in the drawings are often part of the actual structures.

[0036] The vacuum Compton detector belongs to a passive device, and the dark current can reach 10fA-100fA, close to the dark current level introduced by the metal contact potential difference (~0.1eV order of magnitude); as Figure 4 and Figure 5 shown, respectively give the waveform chart of the dark current in the vacuum Compton detector when using iron and aluminum materials as the emitter, it can be seen that when using aluminum material as the emitter, the dark current of the detector is significantly reduced, and thus it can be known that the contact potential difference of different metal materials has a great influence on the size of the dark current in the vacuum Compton detector.

[0037] In order to compensate for the contact potential difference introduced by the core material of different materials between the front end and the terminal of the sensitivity calibration system, thereby reducing the dark current, as Figures 1-3 shown, the present application provides a high signal-to-noise ratio vacuum Compton detector sensitivity calibration system, which comprises a signal line 2, a current meter 3, a connecting head 4 and a compensation module 5.

[0038] As Figure 2As shown, the vacuum Compton detector 1 to be calibrated includes a detector housing 13, an entrance window and an exit window disposed opposite each other on two side walls of the detector housing 13, a detector signal head 14 disposed on the outside of the detector housing 13, an emitter 11 disposed inside the detector housing 13, two end caps 12, and two insulating ceramic pillars 15; the two end caps 12 are respectively connected to the two ends of the emitter 11; the axial direction of the emitter 11 is perpendicular to the opening direction of the entrance window, and one end of each of the two insulating ceramic pillars 15 is connected to the two end caps 12, and the other end is respectively connected to... The inner wall of the detector housing 13 is connected; one end of the detector signal head 14 is connected to the emitter 11 via the signal lead 7, and the other end is connected to the signal line 2; the signal line 2 is a coaxial cable, and the material of the signal lead 7 is the same as that of the signal line 2; the end cap 12 is made of stainless steel; the detector housing 13 is made of stainless steel, and the inside of the detector housing 13 is evacuated to a vacuum level of less than 0.01 Pa; the emitter 11 is made of iron, and the emitter 11 has a circular plate structure with a thickness of 2 mm and a diameter of 50 mm.

[0039] like Figure 3 As shown, the compensation module 5 includes a compensation housing 51, a compensation assembly core disposed within the compensation housing 51, an insulating block 53 disposed around the compensation assembly core, and a compensation signal head 54 disposed outside the compensation housing 51. One end of the signal line 2 is connected to the signal output terminal of the vacuum Compton detector 1. The input terminal of the connector 4 is connected to the other end of the signal line 2. The first output terminal of the connector 4 is connected to the input terminal of the ammeter 3, and the second output terminal is connected to one end of the compensation signal head 54. The compensation signal head 54 is disposed on the compensation housing 51, and the other end is connected to the compensation assembly core via a lead wire 6. An installation cavity is provided inside the insulating block 53, and the compensation assembly core is disposed in the installation cavity. The outer periphery of the insulating block 53 is adapted to the inner wall of the compensation housing 51 to support the compensation assembly core. The insulating block 53 is made of polyethylene.

[0040] The compensation combination core comprises a plurality of compensation cores 52 connected in sequence; the plurality of compensation cores 52 are coaxially arranged and have the same structure; the thickness of the plurality of compensation cores 52 can be designed according to the size of the compensation shell 51 and the size of the installation cavity in the insulation block 53, and the thickness is preferably thin; one compensation core 52 close to the compensation signal head 54 is connected with the compensation signal head 54 through the lead wire 6; it is defined that the total number of the plurality of compensation cores 52 from one end of the connecting lead wire 6 to the other end away from the connecting lead wire 6 is N, 2≤N≤5, which are respectively N1, N2, …, NN; it is defined that from the end cap 12 of the vacuum Compton detector 1 to be calibrated, through the emitter 11, the signal lead-out wire 7, the detector signal head 14 and the signal wire 2 in sequence, one section of the same conductive material is a conductive section, and the total number of the conductive sections is M, 2≤M≤5, which are respectively M1, M2, …, MM; then N=M, and the conductive material of the compensation cores 52 N1, N2, …, NN is the same as that of the conductive sections M1, M2, …, MM, for compensating the contact potential difference introduced by the core material of different materials; in this embodiment, the core material of the lead wire 6, the conductor material of the connecting head 4 and the conductive material of the internal circuit board of the ammeter 3 are the same, which are all aluminum materials, the core material of the input end of the ammeter 3 is the same as that of the signal wire 2; N=M=3, which are respectively N1, N2, N3 and M1, M2, M3; and the conductive material of the compensation cores 52 N1, N2, N3 is the same as that of the conductive sections M1, M2, M3; it should be noted that the material of the above-mentioned compensation combination core is only a preferred embodiment of the present application based on one kind of existing sensitivity calibration system, and in other embodiments of the present application, the compensation combination core with corresponding material can also be set by the person skilled in the art according to the specific setting of the core material in the sensitivity calibration system, so as to achieve the purpose of the contact potential difference introduced by the core material of different materials.

Claims

1. A high signal-to-noise ratio vacuum Compton detector sensitivity calibration system, the vacuum Compton detector (1) to be calibrated comprising an emitter (11), two end caps (12) connected to the emitter (11) respectively, a signal lead-out wire (7) connected to the emitter (11) at one end, and a detector signal head (14) connected to the other end of the signal lead-out wire (7); comprising a signal line (2) and an ammeter (3); one end of the signal line (2) is connected to the detector signal head (14); characterized in that: it further comprises a connecting head (4) and a compensation module (5); the compensation module (5) comprises a compensation shell (51), a compensation combined core arranged in the compensation shell (51), an insulating block (53) arranged on the side of the compensation combined core, and a compensation signal head (54) arranged on the outside of the compensation shell (51); the input end of the connecting head (4) is connected to the other end of the signal line (2), the first output end of the connecting head (4) is connected to the input end of the ammeter (3), and the second output end is connected to one end of the compensation signal head (54); the compensation signal head (54) is arranged on the compensation shell (51), and the other end is connected to the compensation combined core through a lead wire (6); the compensation combined core comprises a plurality of compensation cores (52) connected in sequence; one of the compensation cores (52) close to the compensation signal head (54) is connected to the other end of the compensation signal head (54) through the lead wire (6); a plurality of compensation cores (52) are coaxially arranged; definition: the total number of the plurality of compensation cores (52) from one end of the connecting lead wire (6) to the other end away from the connecting lead wire (6) is N, 2≤N≤5, respectively N1, N2, …, NN; definition: from the end cap (12) in the vacuum Compton detector (1) to be calibrated, in turn through the emitter (11), the signal lead-out wire (7), the detector signal head (14) to the signal line (2), each continuous and same section of conductive material is a conductive section, and the total number of conductive sections is M, 2≤M≤5, respectively M1, M2, …, MM; then N=M, and the conductive material of the compensation cores (52) N1, N2, …, NN is the same as the conductive material of the conductive sections M1, M2, …, MM, which is used to compensate the contact potential difference introduced by different core materials.

2. The high signal-to-noise ratio vacuum Compton detector sensitivity calibration system according to claim 1, characterized in that: an installation cavity is formed in the inside of the insulating block (53), and the compensation combined core is arranged in the installation cavity; the lead wire (6) passes through the insulating block (53) and is connected to the compensation core (52); the outer periphery of the insulating block (53) is matched with the inner wall of the compensation shell (51) to support the compensation combined core.

3. The high signal-to-noise ratio vacuum Compton detector sensitivity calibration system according to claim 2, characterized in that: the material of the insulating block (53) is polyethylene.

4. The high signal-to-noise ratio vacuum Compton detector sensitivity calibration system according to any one of claims 1-3, characterized in that: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The core material of the lead wire (6), the conductor material of the connector (4) and the conductive material of the circuit board inside the ammeter (3) are all aluminum materials, and the core material of the input end of the ammeter (3) is the same as the core material of the signal line (2). N=M=3, respectively N1, N2, N3, and M1, M2, M3, and the conductive material of the compensation core (52) is the same as the conductive material of the M1, M2, M3 conductive section.

5. The high signal-to-noise ratio vacuum Compton detector sensitivity calibration system according to claim 4, wherein: The vacuum Compton detector (1) to be calibrated further comprises a detector shell (13), two insulating ceramic columns (15), an incident window and an exit window oppositely arranged on two side walls of the detector shell (13), and a detector signal head (14) arranged outside the detector shell (13); The emitter (11) and the end cap (12) are both arranged inside the detector shell (13); the axial direction of the emitter (11) is perpendicular to the opening direction of the incident window, one end of each of the two insulating ceramic columns (15) is connected with the two end caps (12) respectively, and the other end of each of the two insulating ceramic columns (15) is connected with the inner wall of the detector shell (13) respectively; One end of the detector signal head (14) is connected with the emitter (11) through a signal lead-out wire (7), and the other end of the detector signal head (14) is connected with the signal line (2); the material of the signal lead-out wire (7) and the material of the detector signal head (14) are the same as the material of the signal line (2).

6. The high signal-to-noise ratio vacuum Compton detector sensitivity calibration system according to claim 5, wherein: The material of the end cap (12) is stainless steel, the material of the emitter (11) is iron, and the material of the signal line (2) is copper.

7. The high signal-to-noise ratio vacuum Compton detector sensitivity calibration system according to claim 6, wherein: The material of the detector shell (13) is stainless steel; the thickness of the emitter (11) is 2mm, and the diameter of the emitter (11) is 50mm; and the vacuum degree inside the detector shell (13) is lower than 0.01Pa.

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