CN112649837B

CN112649837B - Particle identification method, electronic readout system and neutron detector

Info

Publication number: CN112649837B
Application number: CN202011368463.5A
Authority: CN
Inventors: 赵斌清; 王采林
Original assignee: Songshan Lake Materials Laboratory
Current assignee: Songshan Lake Materials Laboratory
Priority date: 2020-11-27
Filing date: 2020-11-27
Publication date: 2021-09-17
Anticipated expiration: 2040-11-27
Also published as: CN112649837A

Abstract

The embodiment of the application provides a particle identification method, an electronics reading system and a neutron detector, wherein the method is applied to the electronics reading system of the neutron detector, the electronics reading system comprises a position measuring module, a discrimination module, a clock synchronization module and a processing module, the electronics reading system takes an anode signal and a dynode signal of a multi-anode photomultiplier as input signals, the type of a particle event is determined based on the dynode signal, and the incident position of the particle is calculated based on multi-channel peak data corresponding to the anode signal. Under the condition that the clock synchronization module provides synchronization signals for the position measurement module, the screening module and the processing module, the processing module simultaneously realizes online measurement of the incident position of the particle and screening of the neutron/gamma event according to multi-channel peak data output by the position measurement module, multi-channel trigger signals and waveform sampling data output by the screening module.

Description

Particle identification method, electronic readout system and neutron detector

Technical Field

The application relates to the technical field of radiation detection, in particular to a particle identification method, an electronics reading system and a neutron detector.

Background

Neutrons are one of the basic particles constituting atomic nuclei, have the characteristics of no electricity, strong penetrability, capability of distinguishing light elements, isotopes, adjacent elements and the like, and non-destructiveness, and the characteristics enable scattered neutrons to become one of ideal probes for researching the microstructure and the dynamic property of a substance.

Scattered neutrons require the use of position sensitive neutron detectors to measure the change in energy and momentum of the scattered neutrons, providing useful information for material structure analysis.

Currently, for most spallation neutron sources, a scintillator detector is used for the measurement of the scattered neutrons. The scintillator detector is mainly composed of ZnS-⁶The device comprises a LiF scintillation screen, a wave-shift optical fiber array, a photoelectric conversion device and a readout electronics system (also called an electronics readout system). After the incident neutrons react with the scintillator in the scintillator detector, the signals are processed by the wave-shift optical fiber array, the photoelectric conversion device and the read-out electronic system, the processed signals are transmitted to a computer end by the read-out electronic system for data analysis, and finally the position of the incident neutrons is obtained by analysis at the computer end. However, since a large amount of gamma (gamma) ray background is associated with the process of measuring incident neutrons and a detector for measuring neutrons is sensitive to gamma rays, the realization of neutron/gamma ray discrimination becomes a key technology of a neutron detection process.

In the conventional technology, a detector for measuring neutrons does not have the capability of discriminating neutrons/gamma rays, the detector is only used for reacting and processing particles passing through the detector, then the processed data is sent to a computer terminal, and the computer terminal performs complex analysis on the data from the detector through specific software.

Disclosure of Invention

The application aims to provide a particle identification method, an electronics reading system and a neutron detector, which can solve the problem that the neutron detector in the prior art cannot realize neutron/gamma ray discrimination and on-line measurement of action positions at the same time.

In a first aspect, an embodiment of the present application provides a particle identification method, which is applied to an electronics readout system of a neutron detector, where the neutron detector includes a multi-anode photomultiplier and the electronics readout system, the electronics readout system includes a position measurement module, a discrimination module, a clock synchronization module, and a processing module, and the method includes:

the clock synchronization module provides synchronization signals for the position measurement module, the screening module and the processing module;

the position measurement module receives an anode signal of the multi-anode photomultiplier, performs gain correction on each channel of the multi-anode photomultiplier, and outputs a multi-channel trigger signal and multi-channel peak data corresponding to a first event, wherein the first event is an event related to the anode signal;

the discriminating module receives dynode signals of the multi-anode photomultiplier and performs signal conversion on the dynode signals to obtain waveform sampling data corresponding to a second event, wherein the second event is an event related to the dynode signals, and the second event is a neutron event or a gamma event;

the processing module determines the particle incident position of the first event and the event type of the second event according to the multi-channel peak data, the multi-channel trigger signal and the waveform sampling data, and determines whether the first event and the second event are the same incident particle event.

By the above method, a solution is proposed that allows particle identification by an electronic readout system of the neutron detector. The electronic reading system takes an anode signal and a dynode signal of a multi-anode photomultiplier as input signals, obtains a multi-channel trigger signal and multi-channel peak data corresponding to the anode signal through a position measuring module, obtains waveform sampling data corresponding to the dynode signal through a screening module, and processes the multi-channel trigger signal, the multi-channel peak data and the waveform sampling data through a processing module of the electronic reading system, so that the action position of a first event corresponding to the anode signal can be measured, the incident position of particles can be obtained, the type of particles can be identified for a second event corresponding to the dynode signal, and the second event corresponding to the dynode signal is determined to be a neutron event or a gamma event. Under the condition that the clock synchronization module provides synchronization signals for the position measurement module, the screening module and the processing module, the processing module can perform correlation processing on data output by the position measurement module and the screening module, so that whether the first event and the second event are the same particle incident event or not is judged, and neutron/gamma ray screening and action position online measurement can be simultaneously realized on the basis.

In an alternative embodiment, the clock synchronization module provides synchronization signals to the position measurement module, the screening module, and the processing module, and includes: the clock synchronization module outputs two groups of clock signals with the same frequency and the same phase by adopting an internal voltage-controlled oscillation mode, provides one group of clock signals in the two groups of clock signals with the same frequency and the same phase to the position measurement module and the processing module, and provides the other group of clock signals in the two groups of clock signals with the same frequency and the same phase to the discrimination module and the processing module.

Through respectively providing clock signals with the same frequency and the same phase for the position measuring module, the screening module and the processing module in the implementation mode, the processing module is favorable for performing correlation processing on data output by the position measuring module and the screening module, and the processing module is favorable for simultaneously realizing online measurement and neutron/gamma ray screening on a neutron incident position.

In an alternative embodiment, the determining, by the processing module, the particle incident position of the first event and the event type of the second event according to the multi-channel peak data, the multi-channel trigger signal, and the waveform sampling data, and determining whether the first event and the second event are the same incident particle event includes: the processing module calculates a particle incident position of the first event according to the multi-channel peak data; the processing module discriminates the second event according to the waveform sampling data and determines the event type of the second event; and the processing module judges whether the first event and the second event are the same incident particle event or not according to the multi-channel peak data, the multi-channel trigger signal and the waveform sampling data.

Through the content related to the processing module in the implementation mode, the implementation mode that the neutron/gamma ray discrimination and the on-line measurement of the action position can be simultaneously realized by the electronic reading system of the neutron detector is provided, and the condition that the gamma ray is mistaken for the incident neutron to obtain the wrong incident position of the neutron can be avoided.

In an optional embodiment, the processing module performs event screening on the second event according to the waveform sampling data, and determines an event type of the second event, including: the processing module performs multi-window integral calculation on the waveform sampling data of the second event to obtain electric charge obtained by integral of each window; and the processing module calculates a charge ratio according to the charge of each window and determines the event type of the second event according to the interval of the charge ratio.

Through the processing content of the waveform sampling data in the implementation manner, the event type of the second event can be determined, so that neutron/gamma ray discrimination is realized.

In an optional embodiment, the determining, by the processing module, whether the first event and the second event are the same incident particle event according to the multi-channel peak data, the multi-channel trigger signal, and the waveform sampling data includes: based on a synchronous signal provided by the clock synchronization module, the processing module determines a target channel from a plurality of channels according to the multi-channel peak data and determines two timing times corresponding to the target channel according to the multi-channel trigger signal, wherein the target channel is a two-dimensional channel with the largest charge peak value in the plurality of channels; the processing module calculates the pulse starting time of the waveform sampling data; and the processing module compares the pulse starting time with the two timing times and judges whether the first event and the second event are the same incident particle event or not according to the comparison result.

Through the content of comparison with the pulse starting time, the two timing times and the corresponding time in the implementation mode, a detailed processing mode capable of associating the online measurement of the incident position of the particle with the particle type identification is provided, and the neutron/gamma ray discrimination and the online measurement of the action position can be simultaneously realized.

In an alternative embodiment, the processing module is a field programmable gate array, and when a first expression is satisfied between the pulse start time and the two timing times, the processing module determines that the first event and the second event are the same incident particle event; the first expression includes: Δ t | | t-t₁|-|t-t₂||<Δ T; where Δ t is the calculated event time difference, t represents the pulse start time corresponding to the waveform sampling data, and t is the pulse start time corresponding to the waveform sampling data₁、t₂Respectively representing two timing times corresponding to the target channel, and delta T is a set time difference.

An implementation is thereby provided in which it may be determined whether the first event and the second event are the same event.

In an optional embodiment, the position measurement module includes a first amplification circuit, a slow-forming amplification circuit, a fast-forming amplification circuit, a threshold trigger circuit, a sample-and-hold circuit, and a first sampling circuit, and the position measurement module receives the anode signals of the multi-anode photomultiplier, performs gain correction on each channel of the multi-anode photomultiplier, and outputs a multi-channel trigger signal and multi-channel peak data corresponding to a first event, and includes: for the anode signal of each channel of the multi-anode photomultiplier, the first amplification circuit receives the anode signal and performs gain correction on the current channel based on the anode signal to obtain two first amplification signals; the first amplifying circuit respectively sends the two paths of first amplifying signals to the slow forming amplifying circuit and the fast forming amplifying circuit; the fast forming amplifying circuit sends an intermediate signal obtained after fast forming processing of one path of first amplifying signal to the threshold value triggering circuit, and the threshold value triggering circuit outputs a triggering pulse as a triggering signal of a current channel when detecting the intermediate signal exceeding a set threshold value; the slow forming amplifying circuit sends an intermediate signal obtained after the slow forming processing of the other path of first amplifying signal to the sampling holding circuit, and the first sampling circuit performs analog-digital conversion on the signal output by the sampling holding circuit and outputs peak data of the current channel.

Through the implementation mode, the implementation mode capable of obtaining the peak data and the trigger signals of each channel of the multi-anode photomultiplier is provided, and the position measurement module can be used for performing gain correction on each channel of the neutron detector to obtain multi-channel peak data.

In an optional embodiment, the screening module includes a low-noise amplifying circuit, a single-end to differential circuit, and a second sampling circuit, and the screening module receives a dynode signal of the multi-anode photomultiplier, and performs signal conversion on the dynode signal to obtain waveform sampling data corresponding to a second event, including: the low-noise amplifying circuit receives and amplifies the dynode signal to obtain a second amplified signal, and the second amplified signal is sent to the single-ended to differential circuit; and the single-ended to differential conversion circuit converts the second amplified signal into a differential signal and then sends the differential signal into the second sampling circuit, and the second sampling circuit performs analog-digital conversion on the differential signal and then outputs the waveform sampling data.

Through the implementation mode, the implementation mode capable of obtaining the waveform sampling data corresponding to the dynode signals is provided, and the discrimination capability of neutron/gamma rays can be improved.

In a second aspect, an electronic readout system is provided in an embodiment of the present application, and is applied to a neutron detector, where the neutron detector includes a multi-anode photomultiplier tube, and the electronic readout system includes: the device comprises a position measuring module, a discrimination module, a clock synchronization module and a processing module;

the clock synchronization module is used for providing synchronization signals for the position measurement module, the screening module and the processing module;

the position measurement module is used for receiving anode signals of the multi-anode photomultiplier, performing gain correction on each channel of the multi-anode photomultiplier, and outputting a multi-channel trigger signal and multi-channel peak data corresponding to a first event, wherein the first event is an event related to the anode signals;

the discriminating module is used for receiving dynode signals of the multi-anode photomultiplier and performing signal conversion on the dynode signals to obtain waveform sampling data corresponding to a second event, wherein the second event is an event related to the dynode signals, and the second event is a neutron event or a gamma event;

the processing module is configured to determine a particle incident position of the first event and an event type of the second event according to the multi-channel peak data, the multi-channel trigger signal, and the waveform sampling data, and determine whether the first event and the second event are the same incident particle event.

With the electronic readout system provided by the second aspect, the particle identification method provided by the first aspect can be performed, and the electronic readout system takes the anode signal and the dynode signal of the multi-anode photomultiplier as input signals, so that neutron/gamma ray discrimination and action position online measurement can be simultaneously realized, and the condition that the gamma ray is mistaken for an incident neutron and an incorrect neutron incident position is obtained can be avoided.

In an optional embodiment, the clock synchronization module is configured to output two sets of clock signals with the same frequency and the same phase by using an internal voltage-controlled oscillation mode, provide one of the two sets of clock signals with the same frequency and the same phase to the position measurement module and the processing module, and provide the other of the two sets of clock signals with the same frequency and the same phase to the screening module and the processing module. Thereby, the measurement accuracy can be improved.

In an alternative embodiment, the position measurement module includes a first amplification circuit, a slow-form amplification circuit, a fast-form amplification circuit, a threshold trigger circuit, a sample-and-hold circuit, and a first sampling circuit; the input end of the first amplifying circuit is used for receiving an anode signal of the multi-anode photomultiplier; two output ends of the first amplifying circuit are respectively connected with the input ends of the slow forming amplifying circuit and the fast forming amplifying circuit; the output end of the fast shaping amplifying circuit is connected with the threshold trigger circuit, and the threshold trigger circuit is used for outputting a trigger signal to the processing module; the output end of the slow forming amplifying circuit is connected with the sampling holding circuit, the sampling holding circuit is connected with the first sampling circuit, and the first sampling circuit is used for outputting peak data to the processing module.

The implementation manner of the position measurement module is provided, and based on the position measurement module, gain correction can be performed on each channel of the multi-anode photomultiplier tube, and data support can be provided for the data processing process of the processing module.

In an optional embodiment, the screening module comprises a low noise amplification circuit, a single-ended to differential circuit, and a second sampling circuit; the input end of the low-noise amplifying circuit is used for receiving the dynode signal; the output end of the low-noise amplifying circuit is connected with the input end of the single-end to differential circuit; the output end of the single-ended to differential conversion circuit is connected with the second sampling circuit, and the second sampling circuit is used for outputting the waveform sampling data to the processing module; wherein the sampling rate of the second sampling circuit is greater than 100 MSPS.

The realization mode about screening the module is provided through the realization mode, the high-resolution requirement on the neutron/gamma ray can be met, and the improvement of the identification accuracy is facilitated.

In an optional embodiment, the low noise amplifying circuit includes a low noise amplifier, a first resistor, a feedback resistor, and a feedback capacitor; the first resistor is connected with the input end of the low noise amplifier, the output end of the low noise amplifier is connected with the input end of the low noise amplifier through the feedback resistor, and the feedback capacitor is connected with the feedback resistor in parallel.

Through the implementation mode, the feedback capacitor is connected in parallel with the feedback resistor of the low-noise amplifier, so that common-mode interference can be reduced, circuit noise is reduced, and waveform digitization precision is improved.

In an alternative embodiment, the single-ended to differential circuit comprises a radio frequency transmission line converter. Therefore, circuit noise can be reduced, and the discrimination capability of neutron/gamma rays is improved.

In a third aspect, embodiments of the present application provide a neutron detector including a multi-anode photomultiplier tube and the electronics readout system of the second aspect.

Through the neutron detector provided by the third aspect, the neutron detector can simultaneously realize neutron/gamma ray screening and online position measurement through the electronics reading system, the performance of the neutron detector is improved, and the calculation complexity of the back-end data of the detector can be reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.

Fig. 1 is a schematic view of a neutron detector provided in an embodiment of the present application.

Fig. 2 is a schematic diagram of an electronic readout system according to an embodiment of the present application.

FIG. 3 is a schematic diagram of an electronic readout system in one example provided by an embodiment of the present application.

Fig. 4 is a schematic topology diagram of a low noise amplifier circuit in an example provided by an embodiment of the present application.

Fig. 5 is a schematic topology diagram of a single-ended to differential circuit in an example provided by an embodiment of the present application.

Fig. 6 is a schematic diagram illustrating an operating principle of a clock synchronization module according to an embodiment of the present application.

Fig. 7 is a functional block diagram of a processing module according to an embodiment of the present disclosure.

Fig. 8 is a schematic diagram of a particle identification method according to an embodiment of the present application.

Fig. 9 is a schematic diagram of pulse division in an example provided by an embodiment of the present application.

Fig. 10 is a schematic diagram of a charge ratio distribution corresponding to a particle event in an example provided by an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

Before describing the technical solution, for the convenience of understanding, the term "background" is described: the measurement background of the detector refers to a non-to-be-measured signal which is measured by the radiation detector and is superposed with a to-be-measured signal. All radiation detectors produce some background signal due to the presence of cosmic rays and natural radioactivity in the environment. These background signals vary significantly depending on the size and type of detector, and also vary with the degree of shielding around the detector. The measurement background of the detector includes a radiation background and a noise background.

Since a great amount of gamma ray background (gamma ray background is a radiation background) is accompanied in the process of measuring neutrons, and a detector for measuring neutrons is sensitive to gamma rays, the gamma rays are easily mistaken for incident neutrons to be measured in the prior art.

In view of the above, the following embodiments are provided by the inventor to improve, and the principle of the embodiment of the present application can simultaneously realize the discrimination of neutron/gamma ray and the measurement of neutron incident position on an electronic system of a neutron detector, and the discrimination of neutron/gamma ray and the online measurement of neutron incident position can be performed by the neutron detector itself, so that the performance of the neutron detector can be improved, the calculation complexity of the back-end data of the neutron detector can be reduced, and the neutron detector system can be simplified.

To facilitate understanding of the technical solutions provided by the embodiments of the present application, a neutron detector provided by the embodiments of the present application will be described below, and the neutron detector includes an electronic readout system provided by the embodiments of the present application, and the electronic readout system can be used for executing the particle identification method provided by the embodiments of the present application (the portions related to the method will be described later).

Referring to fig. 1, fig. 1 is a schematic view of a neutron detector 100 according to an embodiment of the present disclosure.

As shown in fig. 1, the neutron detector 100 includes: a scintillation screen 110, a wave-shifting fiber array 120, a multi-anode photomultiplier tube 130, and an electronics readout system 140.

The scintillation screen 110 is provided with a sensitive detection material, the sensitive detection material is a scintillator, and the scintillator contains⁶Li, the scintillation screen 110 may be ZnS @⁶ LiF scintillator screen 110.

In measuring incident neutrons, the operating principles of the neutron detector 100 may include: incident neutrons and scintillators⁶Li undergoing a nuclear reaction to produce alpha particles and³h nucleus, alpha particles and³the H-nuclei interact with the scintillator to produce scintillation photons. The scintillation photons are absorbed by the wave-shifting fiber array 120 and re-emitted, before being transmitted to the multi-anode photomultiplier 130 coupled to the fiber end-face. The multi-anode photomultiplier tube 130 converts the received optical signals into electrical signals and transmits the converted electrical signals to an electronics readout system 140.

An electronic readout system 140 provided by an embodiment of the present application will be described in detail below.

Referring to fig. 2, fig. 2 is a schematic diagram of an electronic reading system 140 according to an embodiment of the present disclosure. The electronics readout system 140 is applied, among other things, to neutron detectors that include multi-anode photomultipliers.

As shown in fig. 2, the electronic readout system 140 includes: a position measurement module 141, a screening module 142, a clock synchronization module 143, and a processing module 144.

The clock synchronization module 143 is configured to provide synchronization signals to the position measurement module 141, the screening module 142, and the processing module 144.

The position measuring module 141 is configured to receive an anode signal (a in fig. 2 indicates an anode signal) of the multi-anode photomultiplier, perform gain correction on each channel of the multi-anode photomultiplier, and output a multi-channel trigger signal and multi-channel peak data corresponding to the first event. Wherein the first event is an event associated with the anode signal.

The discriminating module 142 is configured to receive a dynode signal (where "B" in fig. 2 represents the dynode signal) of the multi-anode photomultiplier, and perform signal conversion on the dynode signal to obtain waveform sampling data corresponding to the second event. The second event is an event associated with the dynode signal. The second event is a neutron event or a gamma event.

Dynode (dynode), also called dynode, is located between the anode (anode) and cathode (cathode) of the photomultiplier tube.

The processing module 144 is configured to determine a particle incident position of the first event and an event type of the second event according to the multi-channel peak data, the multi-channel trigger signal, and the waveform sampling data, and determine whether the first event and the second event are the same incident particle event.

The working principle of the electronic reading system 140 provided by the embodiment of the present application includes: the anode signal and dynode signal of the multi-anode photomultiplier are used as input signals, the position measuring module 141 outputs a multi-channel trigger signal and multi-channel peak data associated with the anode signal of the multi-anode photomultiplier, the discriminating module 142 outputs waveform sampling data associated with the dynode signal, and the processing module 144 processes, calculates and analyzes the waveform sampling data according to the multi-channel trigger signal, the multi-channel peak data and the waveform sampling data. The processing module 144 may perform online measurement of the action position of the first event corresponding to the anode signal to obtain the particle incident position, and may perform particle type identification of the second event corresponding to the dynode signal to determine whether the second event corresponding to the dynode signal is a neutron event or a gamma event.

It should be noted that, when the clock synchronization module 143 provides synchronization signals for the position measurement module 141, the screening module 142, and the processing module 144, the processing module 144 may perform correlation processing on data output by the position measurement module 141 and the screening module 142, so as to determine whether the first event and the second event are the same particle incident event. If the processing module 144 identifies that the second event is a neutron event and determines that the first event and the second event are the same particle incident event, it can be known that the incident particle location of the first event is indeed the neutron incident location. If the second event is identified as a gamma event, and the first event and the second event are determined to be the same particle incident event, the incident particle position of the first event can be known not to be the action position of the neutron incident particle but to be the action position of the gamma ray. Therefore, the above-mentioned electronic readout system 140 can simultaneously realize neutron/gamma ray discrimination and on-line measurement of action position, and can avoid that the gamma ray is mistaken for the incident neutron, so as to obtain the wrong incident position of the neutron.

The "action site" refers to a site where a neutron particle reacts with a scintillator and reacts, or a site where a gamma ray reacts with a scintillator and reacts.

The electronic readout system 140 and the neutron detector 100 provided by the application can bring the following beneficial effects: compared with the implementation mode that the external device performs a complex analysis processing process through some analysis software to identify the neutron event and the gamma event after the electronic reading system sends all the sampled data to the external device (the external device can be a computer, a mobile terminal or a server) in the prior art, in the embodiment of the application, the electronic reading system 140 of the neutron detector 100 can simultaneously realize the particle event discrimination and the on-line measurement of the action position, so that the performance of the whole neutron detector 100 can be improved, and the calculation complexity of the external device at the rear end of the neutron detector 100 can be simplified.

Where the electronic readout system 140 of the embodiments of the present application includes or is coupled to a display, the particle event screening results and the action location online measurements can be displayed on the display.

The four modules (the position measurement module 141, the discrimination module 142, the clock synchronization module 143, and the processing module 144) included in the electronic readout system 140 in the embodiment of the present application will be described in detail below.

With respect to the position measurement module 141:

the position measurement module 141 may include a plurality of processing channels for respectively receiving the multi-channel anode signals of the multi-anode photomultiplier tube and outputting a set of single-channel trigger signals and single-channel peak data based on each of the multi-channel anode signals. The position measurement module 141 may derive multi-channel trigger signals and multi-channel peak data for the multi-channel anode signals. The number of processing channels of the position measurement module 141 is the same as the number of channels for outputting the anode signal in the multi-anode photomultiplier tube, so that the position measurement module 141 can output the multi-channel trigger signal and the multi-channel peak data matching the number of channels of the multi-anode photomultiplier tube. The particular number of channels should not be construed as limiting the application.

As an implementation of the position measurement module 141, as shown in fig. 3, the position measurement module 141 may include a first amplifying circuit with adjustable gain, a slow-forming amplifying circuit, a fast-forming amplifying circuit, a threshold triggering circuit, a sample-and-hold circuit, and a first sampling circuit.

Wherein the input terminal of the first amplifying circuit is used for receiving an anode signal of the multi-anode photomultiplier (the 'A' in FIG. 3 represents the anode signal). Two output ends of the first amplifying circuit are respectively connected with input ends of the slow forming amplifying circuit and the fast forming amplifying circuit. The output end of the fast shaping amplifying circuit is connected to a threshold trigger circuit, and the threshold trigger circuit is configured to output a trigger signal to the processing module 144. The output end of the slow-forming amplifying circuit is connected to the sample-and-hold circuit, the sample-and-hold circuit is connected to the first sampling circuit, and the first sampling circuit has an analog-to-digital signal conversion function and is configured to output peak data to the processing module 144.

In the position measurement module 141, a first amplification circuit is used to perform gain correction on the anode signal of each channel. Taking the example that the first amplifying circuit is a multi-channel gain-adjustable amplifying circuit, the position measuring module 141 takes the multi-channel anode signals of the multi-anode photomultiplier as input signals, and performs gain correction on the anode signals of each channel through the multi-channel gain-adjustable amplifying circuit. The first amplifying circuit can be realized by an amplifier with a feedback function, and the gain adjustment can be realized by adjusting the feedback resistance of the amplifier (based on the principle, the gain of each channel can be adjusted). The first amplifying circuit can also directly adopt resistors with different resistance values to realize gain correction according to the gain data of each channel.

In the position measurement module 141, the fast-forming amplification circuit and the slow-forming amplification circuit have different time constants, and both the fast-forming amplification circuit and the slow-forming amplification circuit can be realized by using an amplifier having a feedback function. When an amplifier with a feedback capacitor and a feedback resistor is used for building a fast-forming amplifying circuit and a slow-forming amplifying circuit, the pulse rise time of an output waveform can be changed by adjusting the values of the feedback capacitor and the feedback resistor.

In one example, the time constant of the fast shaping amplification circuit may be less than 30 nanoseconds and the time constant of the slow shaping amplification circuit may be between 30 nanoseconds and 300 nanoseconds. Illustratively, a fast-forming amplification circuit and a slow-forming amplification circuit can be built by adopting an amplifier with the model number AD 8002. It is understood that, according to actual needs, those skilled in the art may change the values of the feedback capacitor and the feedback resistor to change the time constant of the amplifying circuit.

In the position measuring module 141, the threshold trigger circuit is used to measure time information, and may output a trigger pulse when detecting that the fast shaping amplifier circuit outputs an intermediate signal exceeding a set threshold. Illustratively, the threshold trigger circuit can be implemented by a chip with models of NINO2 and LM 111.

In the position measurement module 141, the sample-and-hold circuit may perform charge sample-and-hold by using a peak-hold sampling circuit, or may perform charge sample-and-hold by integrating using an integrating circuit. Illustratively, the sample-and-hold circuit may be a chip of model PKD01EY, LTC 6244.

In the position measurement module 141, a first sampling circuit is used to convert an analog signal into a digital signal, so that peak data is sampled. The peak data may be fed to the processing module 144 for the processing module 144 to calculate the particle incident location from the multi-channel peak data.

In one example, the first sampling circuit may be a multi-channel analog-to-digital conversion circuit, and an 8-channel MAX186 chip may be selected for signal conversion. And multi-channel peak data matched with the number of channels of the multi-anode photomultiplier can be obtained through the multi-channel first sampling circuit.

Alternatively, the position measurement module 141 may be a circuit built by discrete components, or may be an integrated chip, for example, the content related to the position measurement module 141 in the embodiment of the present application may be implemented by using an integrated chip capable of outputting a multi-channel trigger signal and a multi-channel peak signal. Illustratively, the company Weercoc, Catiroc series, Maroc series, and Photoroc series of integrated chips can be used.

The operation principle of the position measurement module 141 includes: and receiving the anode signal by the first amplifying circuit, and carrying out gain correction on the current channel based on the anode signal to obtain two paths of first amplifying signals. The two paths of first amplified signals are respectively marked as a first signal and a second signal. The first signal and the second signal are sent to a fast shaping amplifying circuit and a slow shaping amplifying circuit, respectively. The fast forming amplifying circuit sends an intermediate signal obtained after the first signal is subjected to fast forming processing to the threshold value triggering circuit, and the threshold value triggering circuit outputs a triggering pulse as a triggering signal of the current channel when detecting the intermediate signal exceeding a set threshold value. And the slow shaping amplifying circuit sends an intermediate signal obtained after the second signal is subjected to slow shaping processing to the sampling hold circuit. The first sampling circuit performs analog-to-digital conversion on the signal output by the sampling holding circuit and outputs peak data of the current channel.

In an application scenario, a circuit topology structure formed by the first amplifying circuit, the slow forming amplifying circuit, the fast forming amplifying circuit, the threshold triggering circuit, the sample-and-hold circuit and the first sampling circuit can be used as a circuit topology structure for processing a single-channel anode signal. (for the first amplifying circuit processing anode signals of different channels, different gains can be set to amplify anode signals of corresponding channels). In another application scenario, a circuit topology structure formed by the first amplifying circuit, the slow-forming amplifying circuit, the fast-forming amplifying circuit, the threshold triggering circuit, the sample-and-hold circuit and the first sampling circuit can be used as a circuit topology structure for processing a multi-channel anode signal.

Through the implementation manner described above with respect to the position measurement module 141, gain correction can be performed on each channel of the multi-anode photomultiplier, and a trigger signal corresponding to an anode signal of the multi-anode photomultiplier and peak data corresponding to the anode signal of the multi-anode photomultiplier are obtained, which can provide data support for the data processing procedure of the processing module 144.

With respect to the screening module 142:

as shown in fig. 3, the discrimination module 142 may include a low noise amplification circuit, a single-ended to differential circuit, and a second sampling circuit. The input end of the low-noise amplifying circuit is used for receiving the dynode signal. The output end of the low-noise amplifying circuit is connected with the input end of the single-end-to-differential circuit. The output end of the single-ended to differential conversion circuit is connected to the second sampling circuit, and the second sampling circuit is configured to output the waveform sampling data to the processing module 144.

In the discrimination module 142, the low-noise amplification circuit has a feedback function. As shown in FIG. 4, the low noise amplifier circuit may include a low noise amplifier U, a first amplifierResistance R_GA feedback resistor R_FA feedback capacitor C_F. A first resistor R_GConnected with the input end of a low noise amplifier U, the output end of the low noise amplifier U passes through a feedback resistor R_FA feedback capacitor C connected with the input end of the low noise amplifier U_FAnd a feedback resistor R_FAnd (4) connecting in parallel. IN fig. 4, "IN" is the input terminal of the amplifier circuit, to which the dynode signal is inputted, and "OUT 1" is the output signal of the amplifier circuit, which is inputted to the input terminal of the single-ended to differential circuit.

Wherein the feedback resistance R of the low noise amplifier U is used_FUpper parallel feedback capacitor C_FThe method can reduce common mode interference, reduce circuit voltage noise and improve waveform digitization precision.

Illustratively, the low noise amplifier U may be an operational amplifier chip with a model number of AD8021, AD8099, or AD8045, or may be a transimpedance amplifier such as HMC799LP3E, OPA380, or the like.

In the discrimination module 142, the single-ended to differential circuit may use a differential amplifier to convert a single-ended signal into a differential signal, or may directly convert the single-ended signal into a differential signal through a radio frequency transmission line converter (see fig. 5). The radio frequency transmission line converter can reduce circuit noise and improve the discrimination capability for neutron/gamma rays.

As shown in FIG. 5, the single-ended to differential circuit may include a radio frequency transmission line converter, which may be a model TC1-1T +, ETC1-1-13, or the like. Taking as an example a converter with model TC1-1T +, the primary side (PRI) of the converter is used to access the differential signal to be converted (e.g. "OUT 1" in fig. 4) and the secondary Side (SEC) of the converter is used to output the differential signal. The tap on the secondary side of the converter is connected to ground by a capacitor C1 to ground. The two output terminals on the secondary side of the converter output differential signals through the second resistors (i.e., R2, R2 'in fig. 5) and the filter capacitors (i.e., C2, C2' in fig. 5): OUT _ N and OUT _ P.

The signal output by the low-noise amplifying circuit can be amplified through the single-ended to differential circuit, so that the differential signal output by the single-ended to differential circuit can be matched with the input voltage range of the second sampling circuit at the rear end.

In the discrimination module 142, the second sampling circuit is an analog-to-digital conversion circuit that can perform high-speed continuous sampling. The sampling rate of the second sampling circuit may be greater than 100 MSPS. Illustratively, the second sampling circuit can be realized by analog-to-digital conversion chips with the types of LTC2262-14 and LTC 2175-14. The second sampling circuit may send the sampled waveform sample data after analog-to-digital conversion to the processing module 144 for subsequent calculation. The second sampling circuit has a high sampling rate and can meet the high resolution requirement on neutron/gamma rays.

The working principle of the screening module 142 provided by the embodiment of the application includes: based on the low-noise amplifying circuit, the single-end to differential circuit and the second sampling circuit which are sequentially connected in series, the low-noise amplifying circuit receives and amplifies the dynode signal to obtain a second amplified signal, and the second amplified signal is sent to the single-end to differential circuit. The single-ended to differential conversion circuit converts the second amplified signal into a differential signal, and then sends the differential signal to the second sampling circuit, and the second sampling circuit performs analog-to-digital conversion on the differential signal and outputs waveform sampling data for providing to the processing module 144.

With respect to the clock synchronization module 143:

as shown in fig. 3 or fig. 6, the clock synchronization module 143 may include a crystal oscillator and a clock generator. The clock generator can be input to the clock reference of the system through a uniform differential clock source (or a crystal oscillator), and can be realized by adopting a phase-locked loop (PLL) chip. Illustratively, the clock synchronization module 143 may be implemented by a chip of AD9516, CDCM7005, or the like.

As shown in fig. 6, the clock synchronization module 143 can output two sets of clock signals with the same frequency and the same phase by using an internal voltage controlled oscillation mode (the internal voltage controlled oscillation mode can be implemented by a register configuration), and provide one of the two sets of clock signals with the same frequency and the same phase to the position measurement module 141 and the processing module 144, and provide the other of the two sets of clock signals with the same frequency and the same phase to the discrimination module 142 and the processing module 144. The two sets of clock signals with the same frequency and phase may be generated by a clock generator, and the clock generator may further provide the system clock signal and other standby clock signals to the processing module 144. Thereby being beneficial to improving the measurement accuracy.

For example, the "clk _1_ 1" and the "clk _1_ 2" in fig. 6 are a set of clock signals with the same frequency and phase, and the "clk _2_ 1" and the "clk _2_ 2" are another set of clock signals with the same frequency and phase. The clock synchronization module 143 may provide clock signals clk _1_1 and clk _1_2 to a first sampling module and processing module 144, respectively, of the position measurement module 141 and may also provide clk _2_1 and clk _2_2 to a second sampling module and processing module 144, respectively, of the screening module 142. The processing module 144 may obtain the data output by the position measurement module 141 and the screening module 142 according to clk _1_2 and clk _2_ 2.

With respect to the processing module 144:

as shown in fig. 7, the processing module 144 may include a discrimination calculation module 1441, a time measurement module 1442, and a location calculation module 1443. The processing module 144 may be a Field Programmable Gate Array (FPGA), among others.

A discrimination calculation module 1441, configured to obtain the waveform sampling data output by the discrimination module 142, and discriminate an event type of the second event based on the waveform sampling data.

A position calculating module 1443, configured to acquire the multi-channel peak data output by the position measuring module 141, and calculate a particle incident position of the first event based on the multi-channel peak data.

The time measuring module 1442 is configured to obtain the waveform sampling data and the multi-channel trigger signal output by the position measuring module 141, and determine whether the first event and the second event are the same incident particle event based on the waveform sampling data and the multi-channel trigger signal.

Wherein, based on the processing results of the discrimination calculation module 1441, the time measurement module 1442, and the position calculation module 1443, the processing module 144 may output the event type of the second event and the particle incident position of the first event. When the first event and the second event are the same event, the processing module 144 may output the event type and the particle incident position for the same particle event at the same time.

For additional computational details regarding the processing module 144, reference may be made to the description of the embodiments of the present application in relation to the particle identification methods provided below.

The particle identification method provided by the embodiment of the present application will be described in detail below.

Referring to fig. 8, fig. 8 is a flowchart illustrating a particle identification method according to an embodiment of the present application, which can be applied to the electronic readout system and the neutron detector. With regard to the details of the structure of the electronic readout system and the neutron detector, reference may be made to the relevant matters in the foregoing description, and the structure of the electronic readout system and the neutron detector will not be explained below.

As shown in FIG. 8, the method includes steps S21-S24.

S21: the clock synchronization module provides synchronization signals for the position measurement module, the screening module and the processing module.

The synchronous signals can be two groups of clock signals with the same frequency and the same phase, which are output by the clock synchronization module in an internal voltage-controlled oscillation mode. For further details of the clock synchronization module, reference may be made to the aforementioned contents related to the clock synchronization module 143 (e.g., fig. 6), which is not described herein again.

S22: the position measurement module receives anode signals of the multi-anode photomultiplier, performs gain correction on each channel of the multi-anode photomultiplier, and outputs multi-channel trigger signals and multi-channel peak data corresponding to a first event.

S23: the discriminating module receives dynode signals of the multi-anode photomultiplier, and performs signal conversion on the dynode signals to obtain waveform sampling data corresponding to a second event.

S24: the processing module determines the particle incident position of the first event and the event type of the second event according to the multi-channel peak data, the multi-channel trigger signal and the waveform sampling data, and determines whether the first event and the second event are the same incident particle event.

The position measuring module and the discrimination module can respectively determine corresponding sampling periods according to the synchronous signals provided by the clock synchronization module, so as to output data (multi-channel trigger signals, multi-channel peak data and waveform sampling data) which can be provided for the processing module. The processing module can acquire the contents output by the position measuring module and the discrimination module according to the synchronous signals provided by the clock synchronization module, and can calculate multichannel peak value data, multichannel trigger signals and waveform sampling data according to the system clock provided by the clock synchronization module.

The processing module may output a particle incident location and an event type. Under the condition that the processing module is connected with the display, the screened event type and the detected particle incidence position can be displayed on the display, so that a user can know the event type and the particle incidence position of the current event in time.

By the method of S21-S24 described above, a solution is proposed that allows particle identification by the electronic readout system of the neutron detector. Based on the method, the electronic reading system can perform on-line measurement on the action position of a first event corresponding to the anode signal, can perform particle type identification on a second event corresponding to the dynode signal, can correlate the contents of the two events by judging whether the first event and the second event are the same particle incident event or not, and can simultaneously realize neutron/gamma ray discrimination and on-line measurement on the action position on the basis of the correlation, so that the situation that the gamma ray is mistakenly considered as the incident neutron to obtain the wrong neutron incident position can be avoided. When the method is applied to the neutron detector, the data calculation complexity of the rear end of the neutron detector can be simplified.

Optionally, step S24 of the above method may include sub-steps S241-S243. S241 may be performed by a position calculation module of the processing module, S242 may be performed by a discrimination calculation module of the processing module, and S243 may be performed by a time measurement module of the processing module.

S241: the processing module calculates a particle incident position of the first event from the multi-channel peak data.

S242: and the processing module is used for carrying out event screening on the second event according to the waveform sampling data and determining the event type of the second event.

S243: and the processing module judges whether the first event and the second event are the same incident particle event or not according to the multi-channel peak data, the multi-channel trigger signal and the waveform sampling data.

Through the above S241 to S243, when the online measurement of the particle incident position and the particle type identification are performed, the online measurement result of the particle incident position and the particle type identification result are associated with each other, thereby simultaneously realizing the neutron/gamma ray discrimination and the online measurement of the action position.

As an implementation manner of the above S241, the processing module may calculate the peak data of all channels output by the position measurement module by using a gravity center method to calculate the particle incident position of the first event. Thereby the incident position of the particles can be measured on line.

Taking the example of a multi-anode photomultiplier having 2n channels (n is a positive integer, which may be 32, for example), the position measurement module may output 2n trigger signals and 2n peak data according to the anode signals of the 2n channels. The 2n peak data includes peak data in a first direction and peak data in a second direction, where the number of channels in the first direction and the number of channels in the second direction may be the same or different.

Illustratively, the 2n peak data includes peak data of n channels in the first direction and peak data of n channels in the second direction. With x_i、y_iRespectively represents the channel numbers in the first direction and the second direction, i is more than or equal to 1 and less than or equal to n, and Q is used_xi、Q_yiThe peak data of each channel in the first direction and the second direction are respectively expressed, and the particle incidence position of the first event is calculated by (x, y) according to the following expression:

as one implementation of S242 described above, S242 may include sub-steps S2421-S2422.

S2421: and the processing module performs multi-window integral calculation on the waveform sampling data of the second event to obtain electric charges obtained by integrating each window.

S2422: the processing module calculates a charge ratio according to the charges of the windows, and determines an event type of the second event according to an interval where the charge ratio is located.

With respect to S2421-S2422, the processing module can screen the waveform digitized data (waveform sampling data) sampled by the screening module through the second sampling module.

Taking the pulse waveform of the waveform sampling data of two events in one example shown in fig. 9 as an example, the two events correspond to pulse 1 and pulse 2, respectively, and one of the two events is a gamma event and the other is a neutron event.

For a single event which needs to be screened currently, the processing module can divide the pulse waveform of the current event according to the set window number. Taking setting two windows as an example, the pulse waveform can be divided into two segments, and the waveforms at two ends in the two windows are respectively subjected to integral operation to obtain the electric charges corresponding to the two windows: q1, Q2. Then, the charge ratio Q2/Q1 of the current event can be calculated according to the charges Q1 and Q2 corresponding to the two windows. For neutron and gamma events, the theoretically calculated charge ratio Q2/Q1 will be distributed over different intervals (e.g., the charge ratio distribution results shown in FIG. 10).

In practical applications, the charge ratio distribution regions corresponding to the neutron event and the gamma event respectively are related to a scintillator and a photoelectric conversion device at the front end of an electronic readout system, and when incident particles are taken as an event each time, a ratio can be obtained for each event, and after statistical analysis is performed on the charge ratios of multiple neutron events and multiple gamma events, the charge ratio distribution result shown in fig. 10 can be obtained. As shown in fig. 10, the charge ratio of neutron events and gamma events are distributed in different intervals.

In the two sets of statistics shown in fig. 10 (left set, right set), the right set may reflect the charge ratio distribution area of neutron events, the left set may reflect the charge ratio distribution area of gamma events, and the ordinate in fig. 10 may be the number of events. It should be noted that pulse 1 and pulse 2 in fig. 10 are not equivalent to pulse 1 and pulse 2 in fig. 9, pulse 1 in fig. 10 reflects the charge ratio distribution result of multiple gamma events, pulse 2 in fig. 10 reflects the charge ratio distribution result of multiple neutron events, and pulse 1 or pulse 2 in fig. 9 is the waveform sampling result of a single event.

In the embodiment of the present application, the charge ratio interval corresponding to the neutron event and the gamma event can be regarded as a prior value. After the processing module calculates the charge ratio Q2/Q1, the event type of the current event can be known by identifying the interval corresponding to which particle event the Q2/Q1 is in. This allows fast neutron/gamma ray discrimination.

As one implementation of S243 described above, S243 may include sub-steps S2431-S2433. S2431-S2433 may be performed by a time measurement module in the processing module, which may be a precision time measurement circuit in an FPGA.

S2431: based on a synchronous signal provided by the clock synchronization module, the processing module determines a target channel from the multiple channels according to the multi-channel peak data, and determines two timing times corresponding to the target channel according to the multi-channel trigger signal, wherein the target channel is a two-dimensional channel with the largest charge peak value in the multiple channels.

The target channel comprises a channel in a first direction and a channel in a second direction, namely the target channel is a two-dimensional channel. The time measuring module of the processing module can determine the timing time corresponding to each channel according to the trigger signals of all the channels output by the position measuring module. The timing determination can be accomplished by delay line interpolation (TDC) techniques in FPGAs.

S2432: the processing module calculates a pulse start time of the waveform sample data.

S2433: the processing module compares the pulse starting time with the two timing times and judges whether the first event and the second event are the same incident particle event or not according to the comparison result.

For ease of understanding, multi-anode photomultiplier still remainsThe tube has the above 2n channels as an example, and the processing module may determine the channel having the largest charge peak from each of the n channels in the first direction and the n channels in the second direction according to peak data of the 2n channels, so as to determine the target channel. Then, two timing times corresponding to the target channel can be determined according to the trigger signal matched with the target channel: t is t₁、t₂。

And for the waveform sampling data output by the discrimination module, the time measurement module of the processing module can detect the pulse waveform of the waveform sampling data by setting a sampling threshold, and when the rising edge of the pulse waveform of the waveform sampling data is detected to reach the set sampling threshold, the time when the rising edge reaches the set sampling threshold is taken as the pulse starting time t.

At the determined pulse start time t and two timing times t corresponding to the target channel₁、t₂Thereafter, whether the first event and the second time are the same incident particle event can be judged by the following first expression. Wherein, when the pulse start time t and two timing times t₁、t₂The first event and the second event are the same incident particle event when the first expression is satisfied.

The first expression includes: Δ t | | t-t₁|-|t-t₂||<ΔT。

Where Δ t is the calculated event time difference, t represents the pulse start time corresponding to the waveform sampling data, and t is the pulse start time corresponding to the waveform sampling data₁、t₂The two timing times corresponding to the target channels are respectively shown, and delta T is a set time difference.

If according to t₁、t₂And if the event time difference delta T calculated by the T is smaller than the set time difference delta T, the data collected by the position measurement module and the discrimination module correspond to the same event, namely, the first event and the second event are determined to be the same incident particle event.

Through the implementation mode of the S2431-S2433, the neutron detector can effectively correlate the online measurement of the incident position of the particle with the particle type identification, and when the first event and the second event are determined to be the same event, the neutron/gamma ray discrimination and the online measurement of the action position can be completed at the same time.

Optionally, in a case where the position measurement module includes a first amplifying circuit, a slow-shaping amplifying circuit, a fast-shaping amplifying circuit, a threshold triggering circuit, a sample-and-hold circuit, and a first sampling circuit, the S22 may include: S221-S224.

S221: for the anode signal of each channel of the multi-anode photomultiplier, the first amplification circuit receives the anode signal and performs gain correction on the current channel based on the anode signal to obtain two first amplification signals.

S222: the first amplifying circuit sends the two first amplifying signals to the slow forming amplifying circuit and the fast forming amplifying circuit respectively.

S223: the fast forming amplifying circuit sends an intermediate signal obtained after fast forming processing of one path of first amplifying signal to the threshold value triggering circuit, and the threshold value triggering circuit outputs a triggering pulse as a triggering signal of the current channel when detecting the intermediate signal exceeding a set threshold value.

S224: the slow forming amplifying circuit sends an intermediate signal obtained after the slow forming processing of the other path of first amplifying signal to the sample-and-hold circuit, and the first sampling circuit performs analog-digital conversion on the signal output by the sample-and-hold circuit and outputs peak data of the current channel.

For further details regarding S221-S224, reference is made to the above-mentioned related contents regarding the position measurement module 141.

Optionally, when the screening module includes a low-noise amplifying circuit, a single-ended to differential circuit, and a second sampling circuit, the step S23 may include: S231-S232.

S231: the low-noise amplifying circuit receives and amplifies the dynode signal to obtain a second amplified signal, and the second amplified signal is sent to the single-ended to differential circuit.

S232: the single-end-to-differential conversion circuit converts the second amplified signal into a differential signal, and then sends the differential signal to the second sampling circuit, and the second sampling circuit performs analog-digital conversion on the differential signal and outputs waveform sampling data.

For additional details regarding S231-S232, reference is made to the discussion above regarding the screening module 142.

For further details regarding the particle identification method in embodiments of the present application, reference may be made to the foregoing description of the electronics readout system or neutron detector.

In summary, according to the particle identification method, the electronic readout system, and the neutron detector provided in the embodiments of the present application, the electronic readout system uses the anode signal and the dynode signal of the multi-anode photomultiplier as input signals, and for the anode signal, the gain calibration can be performed on each channel of the multi-anode photomultiplier through the gain-adjustable amplification circuit included in the position measurement module, so as to ensure the gain consistency of each channel of the detector, and the particle incident position of the first event can be calculated through multi-channel peak data output by the position measurement module. When the type of the single event, namely the second event, is screened, the charge ratio is obtained by performing multi-window integration on the pulse waveform of the single event, and the event type of the second event is known based on the interval corresponding to the calculated charge ratio. Under the condition that a clock synchronization module is used for providing synchronization signals for a position measurement module, a discrimination module and a processing module, a trigger signal generated by the position measurement module is used as a timing signal, the processing module discriminates whether data acquired by the two modules belong to the same event or not by using a pulse starting signal output by the discrimination module according to a dynode signal and the trigger signal of the position measurement module, so that neutron/gamma ray discrimination and action position measurement processes are correlated, online measurement of particle type discrimination and particle incidence positions is realized, the performance of a neutron detector is improved, and the calculation complexity of the rear end of the neutron detector can be reduced.

The implementation principle provided by the embodiment of the application has better electronics upgrading and expanding capability and is suitable for signal acquisition and processing of the multi-anode photomultiplier with a large number of channels.

It should be noted that, in the description of the above embodiments, the specific chip model should not be construed as limiting the application.

In the embodiments provided in the present application, it should be understood that the disclosed system and method may be implemented in other ways. The above-described embodiments are merely illustrative, and for example, the division of a module is only one division of logic functions, and there may be other divisions in actual implementation, and for example, partial modules and circuits may be combined or may be integrated together to form an independent part, and each module may exist alone, or two or more modules may be integrated to form an independent part.

In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

The above embodiments are merely examples of the present application and are not intended to limit the scope of the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for particle identification, applied to an electronics readout system for a neutron detector, the neutron detector including a multi-anode photomultiplier tube and the electronics readout system, the electronics readout system including a position measurement module, a discrimination module, a clock synchronization module, and a processing module, the method comprising:

2. The method of claim 1, wherein the clock synchronization module provides synchronization signals to the position measurement module, the screening module, and the processing module, comprising:

the clock synchronization module outputs two groups of clock signals with the same frequency and the same phase by adopting an internal voltage-controlled oscillation mode, provides one group of clock signals in the two groups of clock signals with the same frequency and the same phase to the position measurement module and the processing module, and provides the other group of clock signals in the two groups of clock signals with the same frequency and the same phase to the discrimination module and the processing module.

3. The method of claim 1, wherein the processing module determines a particle incident location of the first event and an event type of the second event based on the multi-channel peak data, the multi-channel trigger signal, and the waveform sample data, and determines whether the first event and the second event are the same incident particle event, comprising:

the processing module calculates a particle incident position of the first event according to the multi-channel peak data;

the processing module discriminates the second event according to the waveform sampling data and determines the event type of the second event;

and the processing module judges whether the first event and the second event are the same incident particle event or not according to the multi-channel peak data, the multi-channel trigger signal and the waveform sampling data.

4. The method of claim 3, wherein the processing module event-discriminates the second event based on the waveform sample data and determines an event type of the second event, comprising:

the processing module performs multi-window integral calculation on the waveform sampling data of the second event to obtain electric charge obtained by integral of each window;

and the processing module calculates a charge ratio according to the charges of the windows and determines the event type of the second event according to the interval where the charge ratio is located.

5. The method of claim 3, wherein the processing module determining whether the first event and the second event are the same incident particle event based on the multi-channel peak data, the multi-channel trigger signal, and the waveform sample data comprises:

based on a synchronous signal provided by the clock synchronization module, the processing module determines a target channel from a plurality of channels according to the multi-channel peak data and determines two timing times corresponding to the target channel according to the multi-channel trigger signal, wherein the target channel is a two-dimensional channel with the largest charge peak value in the plurality of channels;

the processing module calculates the pulse starting time of the waveform sampling data;

and the processing module compares the pulse starting time with the two timing times and judges whether the first event and the second event are the same incident particle event or not according to the comparison result.

6. The method of claim 5, wherein the processing module is a field programmable gate array, and wherein the processing module determines that the first event and the second event are the same incident particle event when a first expression is satisfied between the pulse start time and the two timing times;

the first expression includes: Δ t | | t-t₁|-|t-t₂||<ΔT；

Where Δ t is the calculated event time difference, t represents the pulse start time corresponding to the waveform sampling data, and t is the pulse start time corresponding to the waveform sampling data₁、t₂Respectively representing two timing times corresponding to the target channel, and delta T is a set time difference.

7. The method of claim 1, wherein the position measurement module comprises a first amplifying circuit, a slow-forming amplifying circuit, a fast-forming amplifying circuit, a threshold triggering circuit, a sample-and-hold circuit, and a first sampling circuit, and the position measurement module receives the anode signals of the multi-anode photomultiplier, performs gain correction on each channel of the multi-anode photomultiplier, and outputs a multi-channel trigger signal and multi-channel peak data corresponding to a first event, and comprises:

for the anode signal of each channel of the multi-anode photomultiplier, the first amplification circuit receives the anode signal and performs gain correction on the current channel based on the anode signal to obtain two first amplification signals;

the first amplifying circuit respectively sends the two paths of first amplifying signals to the slow forming amplifying circuit and the fast forming amplifying circuit;

the fast forming amplifying circuit sends an intermediate signal obtained after fast forming processing of one path of first amplifying signal to the threshold value triggering circuit, and the threshold value triggering circuit outputs a triggering pulse as a triggering signal of a current channel when detecting the intermediate signal exceeding a set threshold value;

the slow forming amplifying circuit sends an intermediate signal obtained after the slow forming processing of the other path of first amplifying signal to the sampling holding circuit, and the first sampling circuit performs analog-digital conversion on the signal output by the sampling holding circuit and outputs peak data of the current channel.

8. The method according to claim 1, wherein the screening module includes a low-noise amplifying circuit, a single-ended to differential circuit, and a second sampling circuit, and the screening module receives a dynode signal of the multi-anode photomultiplier and performs signal conversion on the dynode signal to obtain waveform sampling data corresponding to a second event, and includes:

the low-noise amplifying circuit receives and amplifies the dynode signal to obtain a second amplified signal, and the second amplified signal is sent to the single-ended to differential circuit;

and the single-ended to differential conversion circuit converts the second amplified signal into a differential signal and then sends the differential signal into the second sampling circuit, and the second sampling circuit performs analog-digital conversion on the differential signal and then outputs the waveform sampling data.

9. An electronic readout system for a neutron detector, the neutron detector including a multi-anode photomultiplier tube, the electronic readout system comprising: the device comprises a position measuring module, a discrimination module, a clock synchronization module and a processing module;

10. An electronic reading system according to claim 9,

the clock synchronization module is used for outputting two groups of clock signals with the same frequency and the same phase by adopting an internal voltage-controlled oscillation mode, providing one group of clock signals with the same frequency and the same phase to the position measurement module and the processing module, and providing the other group of clock signals with the same frequency and the same phase to the discrimination module and the processing module.

11. The electronic readout system of claim 9 wherein the position measurement module comprises a first amplification circuit, a slow-form amplification circuit, a fast-form amplification circuit, a threshold trigger circuit, a sample-and-hold circuit, and a first sampling circuit;

the input end of the first amplifying circuit is used for receiving an anode signal of the multi-anode photomultiplier;

two output ends of the first amplifying circuit are respectively connected with the input ends of the slow forming amplifying circuit and the fast forming amplifying circuit;

the output end of the fast shaping amplifying circuit is connected with the threshold trigger circuit, and the threshold trigger circuit is used for outputting a trigger signal to the processing module;

the output end of the slow forming amplifying circuit is connected with the sampling holding circuit, the sampling holding circuit is connected with the first sampling circuit, and the first sampling circuit is used for outputting peak data to the processing module.

12. The electronic readout system of claim 9 wherein the discrimination module comprises a low noise amplification circuit, a single-ended to differential circuit, a second sampling circuit;

the input end of the low-noise amplifying circuit is used for receiving the dynode signal;

the output end of the low-noise amplifying circuit is connected with the input end of the single-end to differential circuit;

the output end of the single-ended to differential conversion circuit is connected with the second sampling circuit, and the second sampling circuit is used for outputting the waveform sampling data to the processing module;

wherein the sampling rate of the second sampling circuit is greater than 100 MSPS.

13. The electronic readout system of claim 12 wherein the low-noise amplification circuit comprises a low-noise amplifier, a first resistor, a feedback capacitor;

the first resistor is connected with the input end of the low noise amplifier, the output end of the low noise amplifier is connected with the input end of the low noise amplifier through the feedback resistor, and the feedback capacitor is connected with the feedback resistor in parallel.

14. The electronic readout system of claim 12 wherein said single-ended to differential circuit comprises a radio frequency transmission line converter.

15. A neutron detector, characterized by comprising a multi-anode photomultiplier tube and an electronics readout system according to any of claims 9 to 14.