Neutron detector signal reading method, device, system and neutron detector

Abstract

The present invention relates to the field of neutron detection technology, and discloses a neutron detector signal readout method, device, system and neutron detector, the method comprising: obtaining waveform sampling data of each channel of the neutron detector collected by a multi-channel high-speed continuous sampling module when a trigger signal module outputs a trigger signal; counting the number of pulses exceeding a first threshold value in each channel within a preset time length according to the waveform sampling data; selecting a discrimination channel according to the number of pulses exceeding the first threshold value in each channel and judging whether the current detection event is a neutron event or a gamma event according to the waveform sampling data of the discrimination channel; if the current detection event is a neutron event, calculating the neutron position according to the number of pulses exceeding the first threshold value in each channel. The present invention can simultaneously realize neutron incident position measurement and neutron / gamma ray discrimination, simplifying the complexity of the back-end electronics of the neutron detector and the detector system.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron detection, and in particular to a neutron detector signal readout method, device, system and neutron detector. Background Art

[0002] Due to its unique electrical and magnetic properties, neutrons have become ideal probes for studying the microstructure and dynamic properties of matter, and are widely used in many disciplines such as condensed matter physics, nanoscience, protein structure, and material chemistry. In the study of material structure based on neutron scattering technology, it is necessary to use a two-dimensional position-sensitive neutron detector to measure the scattered neutrons, thereby providing effective information for analyzing the structure of the material. This type of detector must have the advantages of high counting rate, high detection efficiency, high position resolution, and high neutron / gamma suppression ratio. Based on 3 He gas neutron detector is the most commonly used and mature neutron detection method. 3 He gas resources are in short supply and expensive, and there is an urgent need to develop alternatives 3 He's new neutron detector is used to meet various scientific research needs.

[0003] In the prior art, the two-dimensional position-sensitive neutron detector is mainly a scintillator neutron position detector. Neutrons generate charged particles through nuclear reactions, causing the scintillator to emit light. The photodetector then performs photoelectric conversion on the scintillation photons to obtain electrical signals, which are then transmitted to the electronics system and data acquisition system. By analyzing the electrical signal, the position of the scintillator where the neutron nuclear reaction occurs, that is, the position of the incident neutron, can be inferred. However, since gamma rays are accompanied in the process of measuring incident neutrons, and the detector measuring neutrons is also very sensitive to gamma rays, the related technology only realizes neutron position measurement through the electronics system, but cannot simultaneously realize neutron / gamma ray discrimination. Summary of the invention

[0004] In view of this, the present invention provides a neutron detector signal readout method, device, system and neutron detector to solve the technical problem that the prior art cannot simultaneously realize neutron / gamma ray discrimination and neutron position measurement.

[0005] In a first aspect, the present invention provides a neutron detector signal readout method, comprising: acquiring waveform sampling data of each channel of the neutron detector collected by a multi-channel high-speed continuous sampling module when a trigger signal module outputs a trigger signal; counting the number of pulses exceeding a first threshold value of each channel within a preset time length according to the waveform sampling data; selecting a discrimination channel according to the number of pulses exceeding the first threshold value of each channel and judging whether the current detection event is a neutron event or a gamma event according to the waveform sampling data of the discrimination channel; if the current detection event is a neutron event, calculating the neutron position according to the number of pulses exceeding the first threshold value of each channel.

[0006] The neutron detector signal readout method of the present invention obtains waveform sampling data of each channel of the neutron detector collected by a multi-channel high-speed continuous sampling module when a trigger signal module outputs a trigger signal, and counts the number of pulses exceeding a first threshold value in each channel within a preset time length according to the waveform sampling data, selects a discrimination channel according to the number of pulses exceeding the first threshold value in each channel, and judges whether the current detection event is a neutron event or a gamma event according to the waveform sampling data of the discrimination channel; if the current detection event is a neutron event, the neutron position is calculated according to the number of pulses exceeding the first threshold value in each channel, and the neutron incident position measurement and neutron / gamma ray discrimination can be realized simultaneously, and the neutron incident position and neutron / gamma ray discrimination results are directly outputted, thereby simplifying the complexity of the back-end electronics and the detector system of the neutron detector and reducing the cost of the neutron detector.

[0007] Optionally, if the current detection event is a neutron event, the neutron position is calculated based on the number of pulses in each channel that exceeds the first threshold, including: if the current detection event is a neutron event, the number of pulses in each channel that exceeds the first threshold is reduced by adding rows and columns to obtain the total number of pulses in several horizontal and vertical channels; the neutron position is calculated based on the total number of pulses in the horizontal and vertical channels.

[0008] In this way, reducing the number of channels by adding rows and columns can reduce the amount of calculation and improve calculation efficiency.

[0009] Optionally, the calculating the neutron position according to the total number of pulses in the horizontal and vertical channels includes: using a center of gravity method to calculate the neutron position according to the total number of pulses in the horizontal and vertical channels, wherein the calculation formula is:

[0010]

[0011] Where (X, Y) is the two-dimensional coordinate of the neutron, E i is the total number of pulses in the i-th channel in the horizontal or vertical direction, (x,y) i is the channel position of the i-th channel in the horizontal direction or the vertical direction, and N is the number of channels in the horizontal direction or the vertical direction.

[0012] In this method, the center of gravity method is used to calculate the neutron position, which can quickly obtain the approximate position of the neutron, and is suitable for preliminary positioning or rapid response scenarios.

[0013] Optionally, the calculating the neutron position according to the total number of pulses in the horizontal and vertical channels includes: using an energy weighted method to calculate the neutron position according to the total number of pulses in the horizontal and vertical channels, wherein the calculation formula is:

[0014]

[0015] Where (X, Y) is the two-dimensional coordinate of the neutron, E i is the total number of pulses in the i-th channel in the horizontal or vertical direction, (x,y) i is the channel position of the i-th channel in the horizontal direction or vertical direction, N is the number of channels in the horizontal direction or vertical direction, and K is the weighting coefficient.

[0016] In this approach, an energy-weighted method is used to take into account the differences in pulse energies of different channels, thereby improving the accuracy of neutron position estimation.

[0017] Optionally, the calculating of the neutron position according to the total number of pulses in the horizontal and vertical channels includes: using a position weighted iteration method to generate an initial neutron position, performing position weighted iteration according to the initial neutron position, stopping the iteration after the number of iterations meets an iteration stop target, and obtaining the neutron position, wherein the calculation formula of the position weighted iteration is:

[0018]

[0019] Where (X, Y) is the two-dimensional coordinate of the neutron, E i is the total number of pulses in the i-th channel in the horizontal or vertical direction, (x,y) i is the channel position of the i-th channel in the horizontal or vertical direction, N is the number of channels in the horizontal or vertical direction, K is the weighting coefficient, e is a natural constant, and j is the number of iterations.

[0020] The neutron position is iteratively optimized by the position weighted iteration method, which improves the positioning accuracy, and the calculation efficiency and accuracy can be balanced by controlling the number of iterations.

[0021] Optionally, the method of selecting a discrimination channel according to the number of pulses exceeding the first threshold in each channel and judging whether the current detection event is a neutron event or a gamma event according to the waveform sampling data of the discrimination channel includes: taking the channel with the largest number of pulses exceeding the first threshold as the discrimination channel, and dividing the waveform sampling data of the discrimination channel into several continuous intervals; counting the number of pulses of the waveform sampling data exceeding a third threshold in a second interval; if the number of pulses exceeding the third threshold in the second interval is greater than a set number, the current detection event is a neutron event, and if the number of pulses exceeding the third threshold in the second interval is less than or equal to a set number, the current detection event is a gamma event.

[0022] The event type is determined by counting the number of pulses exceeding the third threshold in the second interval, thereby improving the accuracy of event type recognition and avoiding misjudgment.

[0023] Optionally, the trigger signal module includes a low-noise amplifier circuit and a discrimination circuit, and the multi-channel high-speed continuous sampling module includes a multi-channel direct connection circuit and a multi-channel high-speed continuous sampling analog-to-digital conversion circuit; correspondingly, the acquisition of waveform sampling data of each channel of the neutron detector collected by the multi-channel high-speed continuous sampling module when the trigger signal module outputs a trigger signal includes: amplifying the dynode signal of the neutron detector through the low-noise amplifier circuit, and outputting a trigger signal to control the multi-channel high-speed continuous sampling module to start sampling when the amplified dynode signal is greater than a second threshold through the discrimination circuit; collecting the anode signal of each channel of the neutron detector through the multi-channel direct connection circuit, and converting the anode signal into a digital signal based on the trigger signal through the multi-channel high-speed continuous sampling analog-to-digital conversion circuit; receiving the digital signal and using the digital signal as the waveform sampling data of each channel of the neutron detector.

[0024] In this method, the low-noise amplifier circuit reduces the noise interference of the signal, the discrimination circuit improves the accuracy of the trigger signal, the multi-channel direct connection circuit and the analog-to-digital conversion circuit ensure the high-speed acquisition and digital processing of the signal, and the trigger signal is generated according to the dynode signal to control the sampling, thereby achieving accurate sampling and providing a high-quality data source for subsequent data analysis.

[0025] In a second aspect, the present invention provides a neutron detector signal reading device, comprising: a waveform acquisition module, used to acquire waveform sampling data of each channel of the neutron detector collected by a multi-channel high-speed continuous sampling module when a trigger signal module outputs a trigger signal; a pulse number statistics module, used to count the number of pulses exceeding a first threshold value of each channel within a preset time length according to the waveform sampling data; an event judgment module, used to select a discrimination channel according to the number of pulses exceeding the first threshold value of each channel and judge whether the current detection event is a neutron event or a gamma event according to the waveform sampling data of the discrimination channel; a position detection module, used to calculate the neutron position according to the number of pulses exceeding the first threshold value of each channel if the current detection event is a neutron event.

[0026] In a third aspect, the present invention provides a neutron detector signal readout system, comprising a trigger signal module, a multi-channel high-speed continuous sampling module and a processing module, wherein the trigger signal module is used to generate a trigger signal, the multi-channel high-speed continuous sampling module is used to collect waveform sampling data of each channel of the neutron detector according to the trigger signal, and the processing module is used to execute the neutron detector signal readout method as described in the first aspect of the present invention and any one of the first aspects.

[0027] In a fourth aspect, the present invention provides a neutron detector, comprising the neutron detector signal readout system as described in the third aspect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 is a schematic flow chart of a neutron detector signal readout method according to an embodiment of the present invention;

[0030] Figure 2 is a schematic structural diagram of a neutron detector signal readout system according to an embodiment of the present invention;

[0031] Figure 3 1 is a waveform diagram of waveform sampling data of a single channel according to an embodiment of the present invention;

[0032] Figure 4 is a schematic diagram of channel reduction after row and column addition in an embodiment of the present invention;

[0033] Figure 5 is a signal schematic diagram of a trigger signal according to an embodiment of the present invention;

[0034] Figure 6 is a schematic diagram of neutron imaging according to an embodiment of the present invention;

[0035] Figure 7 It is a structural block diagram of a neutron detector signal reading device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0037] At present, the existing scintillator neutron detector system can only realize the neutron incident position measurement, does not include the neutron / gamma ray discrimination function, and cannot calculate the neutron incident position calculation and neutron / gamma ray discrimination in real time. Based on this, the embodiments of the present invention propose a neutron detector signal readout method, device, system and neutron detector.

[0038] According to an embodiment of the present invention, a neutron detector signal reading method embodiment is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0039] In this embodiment, a neutron detector signal readout method is provided, which is applied to a processing module, such as a field programmable gate array (FPGA) processing module. The embodiment of the present invention mainly comprises a neutron detector signal readout system through a processing module, a trigger signal module and a multi-channel high-speed continuous sampling module, and realizes neutron detector signal readout through the neutron detector signal readout system.

[0040] like Figure 1 As shown, the process of the neutron detector signal reading method includes the following steps:

[0041] Step S101 , acquiring waveform sampling data of each channel of the neutron detector collected by the multi-channel high-speed continuous sampling module when the trigger signal module outputs a trigger signal.

[0042] Specifically, the trigger signal module determines whether to generate a trigger signal based on a characteristic signal output by the neutron detector itself, such as a sum signal after adding up all channels, or a dynode signal output by the light detector.

[0043] The photodetector is a detection unit in the neutron detector that performs photoelectric conversion on neutron signals. The photodetector can be a photodetector array, position sensitive photomultiplier tubes (PSPMT), microchannel plates (MCP), avalanche photodiode (APD) array, silicon photomultiplier (SiPM), multi-pixel photon counter (MPPC), photomultiplier tubes (PMT).

[0044] In one example, the photodetector is a lithium glass crystal coupled to a single pixel with an area of ​​6×6 mm. 2 The neutron detector has an optical detector array composed of 8×8 multi-anode photomultiplier tubes, and all optical detector channels of the neutron detector are arranged in two dimensions in the horizontal and vertical directions.

[0045] When the dynode signal of the light detector exceeds the set threshold, a square wave signal is generated, which is used as the trigger signal for the neutron detector to collect data. The first falling edge or rising edge of the trigger signal is used as the starting time for counting the number of pulses, and waveform sampling data of each channel of the neutron detector is collected, so that the waveform sampling data includes the statistical period.

[0046] Step S102, counting the number of pulses exceeding a first threshold in each channel within a preset time period according to the waveform sampling data.

[0047] Specifically, the waveform sampling data is pulse counted with the first falling edge or rising edge of the trigger signal. The pulse statistics duration can be terminated until the trigger signal generated by the next event, or the statistics duration can be set to count the number of pulses exceeding the first threshold in each channel within a period of time and record the specific value, which is used for subsequent identification of whether the current detection event is a neutron event or a gamma event, and for calculation of the neutron incidence position.

[0048] Step S103 , selecting a discrimination channel according to the number of pulses in each channel exceeding the first threshold value and judging whether the current detection event is a neutron event or a gamma event according to the waveform sampling data of the discrimination channel.

[0049] Specifically, the waveform sampling data of the channel with the largest number of pulses exceeding the first threshold is counted to determine the number of pulses exceeding the second threshold within a trigger signal statistical interval. When the number of pulses exceeding the second threshold is greater than a set number, for example, greater than 2, it is determined to be a neutron event, otherwise it is a gamma event.

[0050] In one example, the waveform sampling data of the channel with the largest number of pulses exceeding the first threshold can be divided into multiple intervals, and the number of pulses exceeding the second threshold in one of the intervals can be counted. When the number of pulses exceeding the second threshold in the interval is greater than a set number, it is determined to be a neutron event, otherwise it is a gamma event.

[0051] Step S104: If the current detection event is a neutron event, the neutron position is calculated according to the number of pulses in each channel exceeding the first threshold.

[0052] Specifically, when the number of pulses exceeding the first threshold is greater, the neutron positions are denser near the channel position, and the neutron positions are calculated based on this.

[0053] The neutron detector signal readout method of the embodiment of the present invention obtains the waveform sampling data of each channel of the neutron detector collected by the multi-channel high-speed continuous sampling module when the trigger signal module outputs the trigger signal, and counts the number of pulses exceeding the first threshold of each channel within a preset time length according to the waveform sampling data, selects the identification channel according to the number of pulses exceeding the first threshold of each channel, and judges whether the current detection event is a neutron event or a gamma event according to the waveform sampling data of the identification channel; if the current detection event is a neutron event, the neutron position is calculated according to the number of pulses exceeding the first threshold of each channel, and the neutron incident position measurement and neutron / gamma ray discrimination can be realized simultaneously, and the neutron incident position and neutron / gamma ray discrimination results are directly output, which simplifies the complexity of the back-end electronics and the detector system of the neutron detector and reduces the cost of the neutron detector.

[0054] In one embodiment, the trigger signal module includes a low noise amplifier circuit and a discrimination circuit, and the multi-channel high-speed continuous sampling module includes a multi-channel direct connection circuit and a multi-channel high-speed continuous sampling analog-to-digital conversion circuit.

[0055] Correspondingly, in step S101, the waveform sampling data of each channel of the neutron detector collected by the multi-channel high-speed continuous sampling module when the trigger signal module outputs the trigger signal is obtained, including:

[0056] Step S1011, amplifying the dynode signal of the neutron detector by a low-noise amplifier circuit, and outputting a trigger signal to control the multi-channel high-speed continuous sampling module to start sampling when the amplified dynode signal is greater than a second threshold by a discrimination circuit;

[0057] Step S1012, collecting anode signals of each channel of the neutron detector through a multi-channel direct connection circuit, and converting the anode signals into digital signals based on the trigger signal through a multi-channel high-speed continuous sampling analog-to-digital conversion circuit;

[0058] Step S1013, receiving the digital signal and using the digital signal as waveform sampling data of each channel of the neutron detector.

[0059] Specifically, the low-noise amplifier circuit reduces noise interference and performs signal amplification, thereby reducing the noise interference of the signal. The discrimination circuit outputs a trigger signal when the amplified dynode signal is greater than the second threshold, thereby improving the accuracy of the trigger signal.

[0060] The multi-channel direct connection circuit is used to collect the anode signal of each channel, and the analog-to-digital conversion circuit converts the collected anode signal from an analog signal to a digital signal based on the trigger signal to obtain waveform sampling data. Figure 5 As shown in the figure, the waveform sampling data starts with the first falling edge or rising edge of the trigger signal and ends with the falling edge or rising edge of the trigger signal generated by the next event.

[0061] The embodiment of the present invention ensures high-speed acquisition and digital processing of signals, and provides a high-quality data source for subsequent data analysis.

[0062] In one embodiment, in step S104, if the current detection event is a neutron event, the neutron position is calculated according to the number of pulses in each channel exceeding the first threshold, including:

[0063] Step S1041, if the current detection event is a neutron event, the number of pulses exceeding the first threshold in each channel is reduced by row and column addition to obtain the total number of pulses in a number of horizontal and vertical channels;

[0064] Step S1042, calculating the neutron position according to the total number of pulses in the horizontal and vertical channels.

[0065] Exemplarily, the photodetector in the neutron detector is a photodetector array composed of 8×8 multi-anode photomultiplier tubes. All photodetector channels of the neutron detector are arranged in two dimensions in the horizontal and vertical directions. The anode signal of each photodetector channel is output through a multi-channel direct connection circuit, and then the pulse waveform data of each channel is collected through a multi-channel high-speed continuous sampling analog-to-digital conversion circuit. The number of pulses exceeding a first threshold is counted. The first threshold is generally several mV. In the embodiment of the present invention, Figure 3 The voltage shown in the figure is 10mV.

[0066] like Figure 4 As shown in the figure, the horizontal direction is the X direction, the vertical direction is the Y direction, and the X direction and the Y direction are perpendicular to each other. The pulse counts of each channel are added up and reduced to the total pulse counts of 8 X directions and 8 Y directions, i.e., the vertical direction channels. Then, the pulse counts of the above 16 channels are used to calculate the neutron position by using the centroid method, energy weighted method or position weighted iteration method.

[0067] The embodiment of the present invention reduces the number of channels by adding rows and columns, which can reduce the amount of calculation and improve the calculation efficiency.

[0068] In one embodiment, the method of calculating the neutron position in the above step S1042 is:

[0069] The centroid method is used to calculate the neutron position based on the total number of pulses in the horizontal and vertical channels, where the calculation formula is:

[0070]

[0071] Where (X, Y) is the two-dimensional coordinate of the neutron, E i is the total number of pulses in the i-th channel in the horizontal or vertical direction, (x,y) iis the channel position of the i-th channel in the horizontal direction or the vertical direction, and N is the number of channels in the horizontal direction or the vertical direction.

[0072] In this method, the center of gravity method is used to calculate the neutron position, which can quickly obtain the approximate position of the neutron, and is suitable for preliminary positioning or rapid response scenarios.

[0073] In one embodiment, the method of calculating the neutron position in the above step S1042 is:

[0074] The energy-weighted method is used to calculate the neutron position based on the total number of pulses in the horizontal and vertical channels, where the calculation formula is:

[0075]

[0076] Where (X, Y) is the two-dimensional coordinate of the neutron, E i is the total number of pulses in the i-th channel in the horizontal or vertical direction, (x,y) i is the channel position of the i-th channel in the horizontal direction or vertical direction, N is the number of channels in the horizontal direction or vertical direction, and K is the weighting coefficient.

[0077] In this approach, an energy-weighted method is used to take into account the differences in pulse energies of different channels, thereby improving the accuracy of neutron position estimation.

[0078] In one embodiment, the method of calculating the neutron position in the above step S1042 is:

[0079] The position weighted iteration method is used to generate the initial position of the neutron. The position weighted iteration is performed according to the initial position of the neutron. The iteration is stopped when the number of iterations meets the iteration stop target to obtain the neutron position. The calculation formula of the position weighted iteration is:

[0080]

[0081] Where (X, Y) is the two-dimensional coordinate of the neutron, E i is the total number of pulses in the i-th channel in the horizontal or vertical direction, (x,y) i is the channel position of the i-th channel in the horizontal or vertical direction, N is the number of channels in the horizontal or vertical direction, K is the weighting coefficient, e is a natural constant, and j is the number of iterations.

[0082] Specifically, the initial position of the neutron is generated by the center of gravity method or energy weighted method in the above embodiment, which can reduce the number of iterations. The neutron position is iteratively optimized by the position weighted iteration method, which improves the positioning accuracy, and the calculation efficiency and accuracy can be balanced by controlling the number of iterations.

[0083] The position weighted iteration method is used to calculate the neutron position. The incident neutrons are shielded by a long narrow-slit boron carbide neutron shielding plate. The actual measurement results of neutron position imaging are as follows: Figure 6 As shown, it is proved that the neutron detector signal reading method of the embodiment of the present invention is feasible and the position measurement is accurate.

[0084] It should be noted that when the centroid method, energy weighted method and position weighted iteration method are used to calculate the neutron position, only the number of pulses exceeding the first threshold is needed, and no complex electronic structure is required, and no amplification processing is required for each anode signal. It is only necessary to convert the anode signal into a digital signal and output it directly, which can greatly reduce the structure and cost of the neutron detector.

[0085] In one embodiment, step S103, selecting a discrimination channel according to the number of pulses in each channel exceeding a first threshold and judging whether the current detection event is a neutron event or a gamma event according to waveform sampling data of the discrimination channel, includes:

[0086] Step S1031, taking the channel with the largest number of pulses exceeding the first threshold T1 as the identification channel CHm, and dividing the waveform sampling data of the identification channel CHm into a number of continuous intervals (S1, S2, S3, ..., Sn);

[0087] Step S1032, counting the number of pulses of the waveform sampling data exceeding the third threshold value T3 in the second interval S2, and recording the number of pulses exceeding the third threshold value T3 in the second interval S2 as N1.

[0088] Step S1033, if the number of pulses exceeding the third threshold value T3 in the second interval S2 is greater than the set number N, that is, N1>N, then the current detection event is a neutron event; if the number of pulses exceeding the third threshold value T3 in the second interval S2 is less than or equal to the set number N, that is, N1≤N, then the current detection event is a gamma event.

[0089] Specifically, based on the trigger signal, first select the channel with the largest number of pulses exceeding the first threshold value T1 as the identification channel CHm of the neutron gamma event. Then, starting from the trigger signal moment, divide the waveform sampling data corresponding to the identification channel CHm into multiple intervals, such as the first interval S1 with a time interval of 100ns, the second interval S2 with a time interval of 200ns, the third interval S3 with a time interval of 200ns, and the fourth interval S4 until the end of the waveform. After the intervals are divided, the neutron pulse count exceeding the third threshold value T3 in the second interval S2 is counted, and the specific value is recorded as N1. Taking the set number N=2 as an example, if the number of pulses counted in this interval is at least greater than 2, that is, N1>2, it is determined to be a neutron event. If the number of pulses exceeding the third threshold value in the second interval is less than or equal to the set number, that is, N1≤2, then the current detection event is a gamma event.

[0090] The third threshold value can be set according to actual conditions. In one example, the third threshold value is equal to the first threshold value, both of which are 10 mV.

[0091] The event type is determined by counting the number of pulses exceeding the third threshold in the second interval, thereby avoiding sampling errors in the sampling start period, improving the accuracy of event type identification, avoiding misjudgment, and reducing the statistical interval and the statistical amount.

[0092] The embodiment of the present invention also provides a neutron detector signal reading system, such as Figure 2 As shown, it includes a trigger signal module, a multi-channel high-speed continuous sampling module and a processing module. The trigger signal module is used to generate a trigger signal, the multi-channel high-speed continuous sampling module is used to collect waveform sampling data of each channel of the neutron detector according to the trigger signal, and the processing module is used to execute the neutron detector signal reading method as in the above-mentioned embodiment of the present invention.

[0093] Specifically, the trigger signal module includes a low-noise amplifier circuit and a discrimination circuit.

[0094] The multi-channel high-speed continuous sampling module includes a multi-channel direct connection circuit and a multi-channel high-speed continuous sampling analog-to-digital conversion circuit; the processing module adopts a programmable logic array processor, including multi-channel pulse counting and neutron / gamma ray discrimination. The pulse counts of each channel exceeding the first threshold are first counted through the above-mentioned neutron detector signal readout method, and the channel with the most pulse counts is selected for neutron gamma ray discrimination. After determining that it is a neutron event, the pulse count data of each channel of the event are used to calculate the incident neutron position using the center of gravity method, energy weighted method or position weighted iteration method.

[0095] The neutron detector signal readout system of the embodiment of the present invention can realize online neutron incident position measurement and neutron / gamma ray discrimination. Its electronic structure is simpler and more reliable than the scheme of using waveform peak value to calculate the incident neutron position and time type discrimination. It simplifies the detector system, eliminates the need to amplify the signals of each anode, and can directly output the signals, which is also less costly.

[0096] The neutron detector signal readout system of the embodiment of the present invention can be integrated with multiple channels, has good electronic upgrade and expansion capabilities, and is suitable for application scenarios with a large number of neutron detector channels.

[0097] Furthermore, an embodiment of the present invention also provides a neutron detector, including the neutron detector signal readout system as in the above embodiment.

[0098] The neutron detector converts the optical signal into an electrical signal, including a dynode signal and an anode signal, through a photodetector, and then sends the dynode signal and the anode signal to the neutron detector signal readout system for processing.

[0099] The embodiment of the present invention also provides a neutron detector signal reading device, such as Figure 7 As shown, including:

[0100] The waveform acquisition module 701 is used to acquire waveform sampling data of each channel of the neutron detector collected by the multi-channel high-speed continuous sampling module when the trigger signal module outputs a trigger signal;

[0101] The pulse number counting module 702 is used to count the number of pulses exceeding the first threshold value in each channel within a preset time length according to the waveform sampling data;

[0102] An event determination module 703 is used to select a discrimination channel according to the number of pulses in each channel exceeding a first threshold value and to determine whether the current detection event is a neutron event or a gamma event according to waveform sampling data of the discrimination channel;

[0103] The position detection module 704 is used to calculate the neutron position according to the number of pulses exceeding the first threshold in each channel if the current detection event is a neutron event.

[0104] The neutron detector signal readout device of the embodiment of the present invention obtains the waveform sampling data of each channel of the neutron detector collected by the multi-channel high-speed continuous sampling module when the trigger signal module outputs the trigger signal, and counts the number of pulses exceeding the first threshold of each channel within a preset time length according to the waveform sampling data, selects a discrimination channel according to the number of pulses exceeding the first threshold of each channel, and judges whether the current detection event is a neutron event or a gamma event according to the waveform sampling data of the discrimination channel; if the current detection event is a neutron event, the neutron position is calculated according to the number of pulses exceeding the first threshold of each channel, and can simultaneously realize neutron incident position measurement and neutron / gamma ray discrimination, and directly outputs the neutron incident position and neutron / gamma ray discrimination results, thereby simplifying the complexity of the back-end electronics and the detector system of the neutron detector and reducing the cost of the neutron detector.

[0105] Further, the position detection module 704 includes:

[0106] A channel reduction module, for reducing the number of channels by adding the number of pulses exceeding the first threshold in each channel by row and column, if the current detection event is a neutron event, to obtain the total number of pulses in a number of horizontal and vertical channels;

[0107] The position calculation module is used to calculate the neutron position according to the total number of pulses in the horizontal and vertical channels.

[0108] Furthermore, the position calculation module is also used for:

[0109] The centroid method is used to calculate the neutron position based on the total number of pulses in the horizontal and vertical channels, where the calculation formula is:

[0110]

[0111] Where (X, Y) is the two-dimensional coordinate of the neutron, E i is the total number of pulses in the i-th channel in the horizontal or vertical direction, (x,y) i is the channel position of the i-th channel in the horizontal direction or the vertical direction, and N is the number of channels in the horizontal direction or the vertical direction.

[0112] Furthermore, the position calculation module is also used for:

[0113] The energy-weighted method is used to calculate the neutron position based on the total number of pulses in the horizontal and vertical channels, where the calculation formula is:

[0114]

[0115] Where (X, Y) is the two-dimensional coordinate of the neutron, E i is the total number of pulses in the i-th channel in the horizontal or vertical direction, (x,y) i is the channel position of the i-th channel in the horizontal direction or vertical direction, N is the number of channels in the horizontal direction or vertical direction, and K is the weighting coefficient.

[0116] Furthermore, the position calculation module is also used for:

[0117] The position weighted iteration method is used to generate the initial position of the neutron. The position weighted iteration is performed according to the initial position of the neutron. The iteration is stopped when the number of iterations meets the iteration stop target to obtain the neutron position. The calculation formula of the position weighted iteration is:

[0118]

[0119] Where (X, Y) is the two-dimensional coordinate of the neutron, E i is the total number of pulses in the i-th channel in the horizontal or vertical direction, (x,y) i is the channel position of the i-th channel in the horizontal or vertical direction, N is the number of channels in the horizontal or vertical direction, K is the weighting coefficient, e is a natural constant, and j is the number of iterations.

[0120] Furthermore, the event determination module 703 includes:

[0121] A channel selection module, used for selecting the channel with the largest number of pulses exceeding the first threshold as a discrimination channel, and dividing the waveform sampling data of the discrimination channel into a number of continuous intervals;

[0122] An interval pulse statistics module, used for counting the number of pulses of the waveform sampling data exceeding the third threshold in the second interval;

[0123] The interval pulse judgment module is used to determine that if the number of pulses exceeding the third threshold in the second interval is greater than the set number, the current detection event is a neutron event; if the number of pulses exceeding the third threshold in the second interval is less than or equal to the set number, the current detection event is a gamma event.

[0124] Furthermore, the trigger signal module includes a low-noise amplifier circuit and a discrimination circuit, and the multi-channel high-speed continuous sampling module includes a multi-channel direct connection circuit and a multi-channel high-speed continuous sampling analog-to-digital conversion circuit;

[0125] Correspondingly, the waveform acquisition module 701 includes:

[0126] A trigger signal generating module is used to amplify the dynode signal of the neutron detector through a low-noise amplifier circuit, and output a trigger signal through a discrimination circuit to control the multi-channel high-speed continuous sampling module to start sampling when the amplified dynode signal is greater than a second threshold;

[0127] A sampling and conversion module, used to collect anode signals of each channel of the neutron detector through a multi-channel direct connection circuit, and convert the anode signals into digital signals based on a trigger signal through a multi-channel high-speed continuous sampling analog-to-digital conversion circuit;

[0128] The data receiving module is used to receive digital signals and use the digital signals as waveform sampling data of each channel of the neutron detector.

[0129] In the embodiments provided in the present application, it should be understood that the disclosed systems and methods can be implemented in other ways. The embodiments described above are only schematic. For example, the division of modules is only a logical function division. There may be other division methods in actual implementation. For example, some modules and circuits can be combined or integrated to form an independent part. Each module can exist independently, or two or more modules can be integrated to form an independent part.

[0130] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A neutron detector signal reading method, characterized in that: include: Acquire waveform sampling data of each channel of the neutron detector collected by the multi-channel high-speed continuous sampling module when the trigger signal module outputs a trigger signal; Counting the number of pulses exceeding a first threshold value in each channel within a preset time length according to the waveform sampling data; Selecting a discrimination channel according to the number of pulses in each channel exceeding the first threshold value and judging whether the current detection event is a neutron event or a gamma event according to the waveform sampling data of the discrimination channel; If the current detection event is a neutron event, the neutron position is calculated according to the number of pulses in each channel exceeding the first threshold; The selecting a discrimination channel according to the number of pulses in each channel exceeding the first threshold and judging whether the current detection event is a neutron event or a gamma event according to the waveform sampling data of the discrimination channel includes: Using the channel with the largest number of pulses exceeding the first threshold as a discrimination channel, and dividing the waveform sampling data of the discrimination channel into a plurality of continuous intervals; Counting the number of pulses of the waveform sampling data exceeding a third threshold in the second interval; If the number of pulses exceeding the third threshold in the second interval is greater than the set number, the current detection event is a neutron event; if the number of pulses exceeding the third threshold in the second interval is less than or equal to the set number, the current detection event is a gamma event.

2. The neutron detector signal reading method according to claim 1, characterized in that: If the current detection event is a neutron event, calculating the neutron position according to the number of pulses in each channel exceeding the first threshold value includes: If the current detection event is a neutron event, the number of pulses in each channel exceeding the first threshold is reduced by row and column addition to obtain the total number of pulses in a number of horizontal and vertical channels; The neutron position is calculated based on the total number of pulses in the horizontal and vertical channels.

3. The neutron detector signal reading method according to claim 2, characterized in that: The method of calculating the neutron position according to the total number of pulses in the horizontal and vertical channels includes: The centroid method is used to calculate the neutron position based on the total number of pulses in the horizontal and vertical channels, where the calculation formula is: Where (X, Y) is the two-dimensional coordinate of the neutron, E i is the total number of pulses in the i-th channel in the horizontal or vertical direction, (x,y) i is the channel position of the i-th channel in the horizontal direction or the vertical direction, and N is the number of channels in the horizontal direction or the vertical direction.

4. The neutron detector signal reading method according to claim 2, characterized in that: The method of calculating the neutron position according to the total number of pulses in the horizontal and vertical channels includes: The energy-weighted method is used to calculate the neutron position based on the total number of pulses in the horizontal and vertical channels, where the calculation formula is: Where (X, Y) is the two-dimensional coordinate of the neutron, E i is the total number of pulses in the i-th channel in the horizontal or vertical direction, (x,y) i is the channel position of the i-th channel in the horizontal direction or vertical direction, N is the number of channels in the horizontal direction or vertical direction, and k is the weighting coefficient.

5. The neutron detector signal reading method according to claim 2, characterized in that: The method of calculating the neutron position according to the total number of pulses in the horizontal and vertical channels includes: The position weighted iteration method is used to generate the initial position of the neutron, and the position weighted iteration is performed according to the initial position of the neutron. The iteration is stopped after the number of iterations meets the iteration stop target to obtain the neutron position, wherein the calculation formula of the position weighted iteration is: Where (X, y) is the two-dimensional coordinate of the neutron, e i is the total number of pulses in the Ith channel in the horizontal or vertical direction, (x, y) i is the channel position of the i-th channel in the horizontal or vertical direction, N is the number of channels in the horizontal or vertical direction, K is the weighting coefficient, e is a natural constant, and J is the number of iterations.

6. The neutron detector signal reading method according to claim 1, characterized in that: The trigger signal module includes a low-noise amplifier circuit and a discrimination circuit, and the multi-channel high-speed continuous sampling module includes a multi-channel direct connection circuit and a multi-channel high-speed continuous sampling analog-to-digital conversion circuit; Correspondingly, the waveform sampling data of each channel of the neutron detector collected by the multi-channel high-speed continuous sampling module when the trigger signal module outputs the trigger signal includes: Amplifying the dynode signal of the neutron detector by the low-noise amplifier circuit, and outputting a trigger signal by the discrimination circuit when the amplified dynode signal is greater than a second threshold value to control the multi-channel high-speed continuous sampling module to start sampling; The anode signal of each channel of the neutron detector is collected by the multi-channel direct connection circuit, and the anode signal is converted into a digital signal based on the trigger signal by the multi-channel high-speed continuous sampling analog-to-digital conversion circuit; The digital signal is received and used as waveform sampling data of each channel of the neutron detector.

7. A neutron detector signal reading device, characterized in that: include: A waveform acquisition module is used to acquire waveform sampling data of each channel of the neutron detector collected by the multi-channel high-speed continuous sampling module when the trigger signal module outputs a trigger signal; A pulse number statistics module, used for counting the number of pulses exceeding a first threshold value in each channel within a preset time length according to the waveform sampling data; An event judgment module, used for selecting a discrimination channel according to the number of pulses in each channel exceeding the first threshold value and judging whether the current detection event is a neutron event or a gamma event according to the waveform sampling data of the discrimination channel; A position detection module, configured to calculate the neutron position according to the number of pulses in each channel exceeding the first threshold value if the current detection event is a neutron event; The event judgment module includes: A channel selection module, used for selecting the channel with the largest number of pulses exceeding the first threshold as a discrimination channel, and dividing the waveform sampling data of the discrimination channel into a number of continuous intervals; An interval pulse statistics module, used for counting the number of pulses of the waveform sampling data exceeding the third threshold in the second interval; The interval pulse judgment module is used to determine that if the number of pulses exceeding the third threshold in the second interval is greater than the set number, the current detection event is a neutron event; if the number of pulses exceeding the third threshold in the second interval is less than or equal to the set number, the current detection event is a gamma event.

8. A neutron detector signal readout system, characterized in that: It includes a trigger signal module, a multi-channel high-speed continuous sampling module and a processing module. The trigger signal module is used to generate a trigger signal. The multi-channel high-speed continuous sampling module is used to collect waveform sampling data of each channel of the neutron detector according to the trigger signal. The processing module is used to execute the neutron detector signal reading method as described in any one of claims 1 to 6.

9. A neutron detector, characterized in that: Comprising the neutron detector signal readout system as claimed in claim 8.

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