A coding multiplexing method for reading array-type plastic scintillator detectors

Abstract

The present application discloses a coding multiplexing method for reading out an array type plastic scintillator detector, and relates to the field of particle detection technology. The method includes designing the cross-sectional shape, arrangement mode and numbering of each plastic flash bar in a one-dimensional plastic flash bar array, so that it meets the requirement that when the detected particle hits the array type plastic scintillator detector, it must hit at least two plastic flash bars with continuous positions and continuous numbers; according to the cross-sectional shape, arrangement mode and numbering of each plastic flash bar, determine the coding parameters based on the detector channel and the signal readout channel; generate a coding table according to the coding parameters; establish a detection readout framework according to the coding table, perform particle detection on the detected particle, and reversely infer the hit detector channel according to the number corresponding to the signal readout channel that receives the signal during the detection process. The present application can reduce the number of required signal readout channels and reduce the complexity and cost of the electronic system.

Description

Technical Field

[0001] The present application relates to the field of particle detection technology, and in particular to a coding multiplexing method applied to readout of an array-type plastic scintillator detector. Background Art

[0002] Plastic scintillator is a solid solution of organic scintillating material in plastic, usually composed of matrix scintillating material and wave shifter. Plastic scintillator has the advantages of strong plasticity, short luminescence decay time, stable performance, high mechanical strength, easy storage, good radiation resistance, etc. It can measure β rays, X rays, gamma rays, protons, neutrons and other rays or particles, and is widely used in particle measurement, such as TOF (Time Of Flight) experiment, EAS (Energy during Avalanche for Single pulse) experiment, shower calorimeter and medical imaging.

[0003] Plastic scintillator detectors are a type of detector that uses particles to deposit energy in plastic scintillators to make the substances in them produce fluorescence for particle detection. They are also one of the most widely used ionizing radiation detectors. In order to improve the position resolution of plastic scintillator detectors, a common practice is to divide the plastic scintillator into smaller units, wrap each unit (to avoid light and increase reflectivity), and then form an array to form an array-type plastic scintillator detector. The most common one is a one-dimensional array composed of rectangular plastic flash strips. However, in order to improve the position resolution of plastic scintillator detectors, it is often necessary to reduce the strip width of the plastic flash strip. According to the traditional signal readout method, each plastic flash strip requires a photoelectric conversion device to convert its optical signal into an electrical signal. Among them, SiPM (Silicon PhotoMultiplier, silicon photomultiplier tube) and PMT (PhotoMultiplier Tube, photomultiplier tube) are commonly used, and then the signal is collected and transmitted to the subsequent signal processing system through an electronic channel. In the application process, in order to achieve better position resolution, the strip width will be reduced. Under the condition of the same detector area, the number of plastic flash strips will increase, and the required photoelectric conversion devices and electronic channels will also increase greatly. Accordingly, the complexity, cost, and power consumption of the entire electronic system for signal readout will also increase. Therefore, how to reduce the number of required photoelectric conversion devices and electronic channels to reduce the complexity, cost, and power consumption of the electronic system is an urgent problem to be solved.

[0004] At present, the direct coding readout scheme can be used as a reference implementation scheme for compressing the number of photoelectric conversion devices and electronic channels for the readout of array-type plastic scintillator detectors. The direct coding readout scheme is to encode the detector channels (corresponding to the plastic scintillator detector whose main body is the plastic scintillator strip) and map the set of detector channels to the set of signal readout channels (corresponding to the plastic scintillator detector whose main body is the electronic channel or the photoelectric conversion device plus the electronic channel) according to the coding rules, so as to directly multiplex the electronic channels (and the photoelectric conversion device) to achieve the compression of the number of electronic channels (and the photoelectric conversion device). Among them, both encoding and decoding are based on the characteristic that the detector channels hit by particles are continuous, that is, when a particle hits a layer of detectors, it must hit at least two continuous detector channels. The coding scheme should meet the following three conditions: (1) One signal readout channel reads multiple detector channels; (2) A pair of continuous detector channels is uniquely mapped to a pair of disordered signal readout channels; (3) The two detector channels mapped to the same signal readout channel are far enough apart that they will not receive the signal of the same particle event at the same time. Then, the particle impact position can be uniquely inferred based on the signal readout channel number of the readout particle event signal. By designing the shape and arrangement of the plastic flash bar array to ensure the continuity of the detector channel response when the particle to be measured hits, the influence of false events on the results can be well avoided, further improving the detector accuracy.

[0005] Based on this, in view of the problem in the prior art that as the position resolution requirements of array-type plastic scintillator detectors become higher, the number of plastic scintillator strips increases, the number of required signal readout channels increases accordingly, and the complexity and cost of the electronic system increase accordingly, how to provide a coding multiplexing method that can reduce the number of required signal readout channels and reduce the complexity and cost of the electronic system has become a technical problem that needs to be urgently solved in this field. Summary of the invention

[0006] The purpose of the present application is to provide a coding multiplexing method for readout of an array-type plastic scintillator detector, which can reduce the number of required signal channels and reduce the complexity and cost of the detection system.

[0007] To achieve the above objectives, this application provides the following solutions.

[0008] The present application proposes a coding multiplexing method for reading out an array-type plastic scintillator detector. The array-type plastic scintillator detector includes a one-dimensional plastic flash bar array, and the one-dimensional plastic flash bar array includes a plurality of plastic flash bars. The coding multiplexing method for reading out an array-type plastic scintillator detector includes the following steps.

[0009] The cross-sectional shape, arrangement and numbering of each plastic flash strip in the one-dimensional plastic flash strip array are designed to meet the requirement that when the particles to be detected hit the array-type plastic scintillator detector, they must hit at least two plastic flash strips with continuous positions and continuous numbers.

[0010] According to the cross-sectional shape, arrangement and numbering of each plastic flash strip, the signals of multiple plastic flash strips are merged into one signal readout channel, and the coding parameters based on the detector channel and the signal readout channel are determined; the coding parameters include the shortest multiplexing period, the multiplexing rate, the number of detector channels and the number of signal readout channels. The shortest multiplexing period is the minimum difference in the numbers of two detector channels connected to the same signal readout channel, and the multiplexing rate is the ratio of the number of detector channels to the number of signal readout channels.

[0011] A coding table is generated according to the coding parameters; the coding table is used to represent the mapping relationship between the detector channel and the signal readout channel.

[0012] A detection readout framework is established according to the coding table to detect the particles to be detected. The detector channel that was hit is inferred based on the number corresponding to the signal readout channel that received the signal during the detection process.

[0013] Optionally, before the step of merging the signals of multiple plastic flash strips into one signal readout channel according to the cross-sectional shape, arrangement and numbering of each plastic flash strip, and determining the coding parameters based on the detector channel and the signal readout channel, the coding multiplexing method applied to the readout of the array-type plastic scintillator detector also includes the following steps.

[0014] Determine the signal readout channel multiplexing method and define the detector channel and signal readout channel.

[0015] Optionally, determining a signal readout channel multiplexing mode and defining a detector channel and a signal readout channel specifically includes the following steps.

[0016] For each plastic flash strip, a direct or indirect export method is used to export the optical signal generated by the plastic flash strip, and the signal readout channel is multiplexed; wherein, the indirect export method is to use a method including whole-strip burial or termination to couple the wavelength-shifted optical fiber with the plastic flash strip, and export the optical signal generated by the plastic flash strip to the photoelectric conversion device; the direct export method is to directly couple the plastic flash strip with the photoelectric conversion device, and directly detect the optical signal generated by the plastic flash strip.

[0017] The signal readout channel multiplexing method is a connection method of a wavelength shifting optical fiber coupled with a plastic flash strip, a photoelectric conversion device and an electronic channel, including the following two forms.

[0018] The first form is that a plurality of wavelength shifting optical fibers are connected to an optoelectronic conversion device, and the optoelectronic conversion device is further connected to an electronic channel.

[0019] The second form is that each plastic flash strip is coupled to a wavelength-shifting optical fiber and then connected to a photoelectric conversion device, and multiple photoelectric conversion devices are connected to the same subsequent electronic channel; or, the plastic flash strip is directly coupled to the photoelectric conversion device, and multiple photoelectric conversion devices are connected to the same subsequent electronic channel.

[0020] Based on the signal readout channel multiplexing method, detector channels and signal readout channels are defined, including the following two methods.

[0021] The first method is that when the signal readout channel multiplexing method is the first form, the channel path from each plastic flash strip to the wavelength-shifted optical fiber is defined as a detector channel, and the subsequent photoelectric conversion device and the electronic channel connected thereto are defined as a signal readout channel.

[0022] The second method is that when the signal readout channel multiplexing method is the second form, the channel path from each plastic flash strip to the photoelectric conversion device is defined as a detector channel, and the same electronic channel connecting multiple photoelectric conversion devices is defined as a signal readout channel.

[0023] Optionally, according to the cross-sectional shape, arrangement and numbering of each plastic flash strip, the signals of multiple plastic flash strips are merged into one signal readout channel, and the coding parameters based on the detector channel and the signal readout channel are determined, which specifically includes the following steps.

[0024] The number of plastic flash strips is determined based on the cross-sectional shape, arrangement and size of the plastic flash strips and the area of ​​the detector. The number of detector channels is equal to the number of plastic flash strips.

[0025] According to the number of plastic flash strips and the requirements for multiplexing rate, the signals of multiple plastic flash strips are merged into one signal readout channel, and the number of photoelectric conversion devices and the number of electronic channels are determined.

[0026] According to the number of photoelectric conversion devices and the number of electronic channels, the electronic channels are numbered to determine the number and number of signal readout channels.

[0027] The shortest reuse period is determined based on the physical properties of the particles to be tested and the cross-sectional shape, arrangement and numbering of the plastic flash strips.

[0028] Optionally, generating a coding table according to coding parameters specifically includes the following steps.

[0029] A coding table is generated according to the coding parameters and in combination with coding rules; the coding rules include a multiplexing rule and a unique continuity rule. The multiplexing rule is that one signal readout channel reads out multiple detector channels, and the unique continuity rule is that each pair of detector channels with consecutive positions and consecutive numbers is uniquely mapped to a pair of unordered signal readout channels.

[0030] Optionally, a detection readout framework is established according to the coding table, the particles to be detected are detected, and the hit detector channel is inferred according to the number corresponding to the signal readout channel that receives the signal during the detection process, which specifically includes the following steps.

[0031] According to the mapping relationship between the detector channel and the signal readout channel in the coding table, the detector channel is connected to the corresponding signal readout channel to form a detection readout framework.

[0032] The detection readout framework is used to detect the particles to be detected, and the number corresponding to the signal readout channel receiving the signal during the detection process is obtained.

[0033] According to the number corresponding to the signal readout channel of the received signal and the continuity characteristic of the hit detector channel, the hit detector channel is inferred in reverse.

[0034] According to the specific embodiments provided in this application, this application discloses the following technical effects.

[0035] The present application provides a coding multiplexing method for reading out an array-type plastic scintillator detector. By designing the cross-sectional shape, arrangement and numbering of plastic flash bars, the requirement that a particle to be detected must hit at least two plastic flash bars with continuous positions and continuous numbers when hitting the array-type plastic scintillator detector is met. Then, a coding table characterizing the mapping relationship between the detector channel and the signal readout channel is generated according to the coding parameters, and a detection readout framework is established according to the coding table. In the process of detecting the particle to be detected using the detection readout framework, the hit detector channel can be accurately and reliably inferred based on the coding table and the number of the signal readout channel that receives the particle event electrical signal, so as to accurately reconstruct the actual hitting position. Without changing the detector structure and without reducing the position resolution, the coding multiplexing principle based on the detector channel and the signal readout channel is utilized to infer the impact position of the particle through the mapping relationship between the detector channel and the signal readout channel. By multiplexing the signal readout channel, the number of required signal readout channels can be effectively reduced, and the complexity and cost of the electronic system can be reduced. This solves the problem in the prior art that as the position resolution of the array-type plastic scintillator detector improves, the number of plastic scintillator strips increases, the number of required signal readout channels increases accordingly, and the complexity and cost of the electronic system increase accordingly. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A schematic flow chart of a coding multiplexing method for reading out an array-type plastic scintillator detector provided in one embodiment of the present application.

[0038] Figure 2 A principle flow chart of a coding multiplexing method applied to readout of an array-type plastic scintillator detector provided in one embodiment of the present application.

[0039] Figure 3 A schematic diagram of the structure of a plastic scintillator array coupled with a wavelength-shifting optical fiber provided in one embodiment of the present application.

[0040] Figure 4 A partially numbered Euler encoding diagram provided for an embodiment of the present application.

[0041] Figure 5 A schematic diagram of partial channel connections provided in one embodiment of the present application. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] like Figure 1 As shown, this embodiment proposes a code multiplexing method for reading out an array type plastic scintillator detector, wherein the array type plastic scintillator detector includes a one-dimensional plastic scintillator strip array, wherein the one-dimensional plastic scintillator strip array includes a plurality of plastic scintillator strips, wherein the plastic scintillator strip is short for plastic scintillator strip, and refers to a strip-shaped plastic scintillator. The code multiplexing method for reading out an array type plastic scintillator detector specifically includes the following steps.

[0044] Step S1, designing the cross-sectional shape, arrangement and numbering of each plastic flash bar in the one-dimensional plastic flash bar array so that the particles to be detected will hit at least two plastic flash bars with consecutive positions and consecutive numbers when hitting the array-type plastic scintillator detector.

[0045] Step S2: According to the cross-sectional shape, arrangement and number of each plastic flash strip, the signals of multiple plastic flash strips are merged into one signal readout channel, and the coding parameters based on the detector channel and the signal readout channel are determined. The coding parameters include the shortest multiplexing cycle, the multiplexing rate, the number of detector channels and the number of signal readout channels. The shortest multiplexing cycle is the minimum difference in the numbers of two detector channels connected to the same signal readout channel, and the multiplexing rate is the ratio of the number of detector channels to the number of signal readout channels.

[0046] Step S3: Generate a coding table according to the coding parameters, wherein the coding table is used to represent the mapping relationship between the detector channel and the signal readout channel.

[0047] Step S4, establish a detection readout framework according to the coding table, detect the particles to be detected, and reversely infer the hit detector channel according to the number corresponding to the signal readout channel receiving the signal during the detection process.

[0048] In this embodiment, step S1 designs the cross-sectional shape, arrangement and numbering of each plastic flash strip in the one-dimensional plastic flash strip array, and specifically includes the following steps.

[0049] The cross-sectional shape and arrangement of the plastic flash strips in the one-dimensional plastic flash strip array are designed, and each plastic flash strip is numbered in sequence, so that the cross-sectional shape, arrangement and numbering of each plastic flash strip meet the requirement that when the particles to be measured hit the array-type plastic scintillator detector, they must hit at least two plastic flash strips with continuous positions and continuous numbers.

[0050] In this embodiment, before step S2, according to the cross-sectional shape, arrangement and number of each plastic flash strip, the signals of multiple plastic flash strips are merged into one signal readout channel, and the coding parameters based on the detector channel and the signal readout channel are determined, the following steps may also be included.

[0051] Step S1.5, determine the signal readout channel multiplexing mode, and define the detector channel and the signal readout channel.

[0052] In this embodiment, step S1.5 determines the signal readout channel multiplexing mode and defines the detector channel and the signal readout channel, which specifically includes the following steps.

[0053] Step S1.51, for each plastic flash strip, use a direct export method or an indirect export method to export the optical signal generated by the plastic flash strip, and multiplex the signal readout channel; wherein the indirect export method is to use a method including whole-strip embedding or termination to couple the wavelength-shifting optical fiber with the plastic flash strip, and export the optical signal generated by the plastic flash strip to the photoelectric conversion device; the direct export method is to directly couple the plastic flash strip with the photoelectric conversion device, and directly detect the optical signal generated by the plastic flash strip.

[0054] Step S1.52, the signal readout channel multiplexing method is a connection method of the wavelength-shifting optical fiber coupled with the plastic flash strip, the photoelectric conversion device and the electronic channel, including the following two forms.

[0055] The first form is that a plurality of wavelength shifting optical fibers are connected to an optoelectronic conversion device, and the optoelectronic conversion device is further connected to an electronic channel.

[0056] The second form is that each plastic flash strip is connected to a photoelectric conversion device (this process can be done by connecting the optical signal to the photoelectric conversion device through a wavelength-shifting optical fiber, or by directly coupling the photoelectric conversion device to the plastic flash strip), and multiple photoelectric conversion devices are connected to the same subsequent electronic channel. In other words, each plastic flash strip is connected to a photoelectric conversion device after coupling the wavelength-shifting optical fiber, and multiple photoelectric conversion devices are connected to the same subsequent electronic channel; or, the plastic flash strip is directly coupled to the photoelectric conversion device, and multiple photoelectric conversion devices are connected to the same subsequent electronic channel.

[0057] Step S1.53, based on the signal readout channel multiplexing method, define the detector channel and the signal readout channel, including the following two methods.

[0058] The first method is that when the signal readout channel multiplexing method is the first form, the channel path from each plastic flash strip to the wavelength-shifted optical fiber is defined as a detector channel, and the subsequent photoelectric conversion device and the electronic channel connected thereto are defined as a signal readout channel.

[0059] The second method is that when the signal readout channel multiplexing method is the second form, the channel path from each plastic flash strip to the photoelectric conversion device is defined as a detector channel, and the same electronic channel connecting multiple photoelectric conversion devices is defined as a signal readout channel.

[0060] In this embodiment, step S2 combines the signals of multiple plastic flash strips into one signal readout channel according to the cross-sectional shape, arrangement and number of each plastic flash strip, and determines the coding parameters based on the detector channel and the signal readout channel, which specifically includes the following steps.

[0061] Step S21, determining the number of plastic flash strips according to the cross-sectional shape, arrangement mode and size of the plastic flash strips and the area of ​​the detector, and the number of detector channels is equal to the number of plastic flash strips.

[0062] Step S22: According to the number of plastic flash strips and the requirement for multiplexing rate, the signals of multiple plastic flash strips are merged into one signal readout channel, and the number of photoelectric conversion devices and the number of electronic channels are determined.

[0063] Step S23: number the electronic channels according to the number of photoelectric conversion devices and the number of electronic channels, and determine the number and number of signal readout channels.

[0064] Step S24, determining the shortest reuse period according to the physical properties of the particles to be tested and the cross-sectional shape, arrangement and numbering of the plastic flash strips.

[0065] In this embodiment, the number of plastic flash bars, the number of electronic channels and the reuse rate are three interrelated parameters. The number of plastic flash bars is determined by factors such as their shape, size, arrangement, and detector area. The number of electronic channels and the reuse rate are determined according to specific circumstances. For example, when the number of electronic channels is limited by objective factors such as space and cannot exceed a certain value, the reuse rate is also limited accordingly. The shortest reuse period is restricted by the physical properties of the particles to be measured and the shape, size, arrangement and numbering of the plastic flash bars, and has nothing to do with the numbering of the electronic channels.

[0066] In this embodiment, step S3 generates a coding table according to the coding parameters, which specifically includes the following steps.

[0067] The coding table is generated according to the coding parameters and the coding rules. The coding rules include multiplexing rules and unique continuity rules. The multiplexing rule is that one signal readout channel reads multiple detector channels, and the unique continuity rule is that each pair of detector channels with consecutive positions and consecutive numbers is uniquely mapped to a pair of unordered signal readout channels.

[0068] In this embodiment, step S4 establishes a detection readout framework according to the coding table, detects the particles to be detected, and reversely infers the hit detector channel according to the number corresponding to the signal readout channel receiving the signal during the detection process, which specifically includes the following steps.

[0069] Step S41: According to the mapping relationship between the detector channel and the signal readout channel in the coding table, the detector channel is connected to the corresponding signal readout channel to form a detection readout framework.

[0070] Step S42: Use the detection readout framework to detect the particles to be detected, and obtain the number corresponding to the signal readout channel that receives the signal during the detection process.

[0071] Step S43, according to the signal reading channel number corresponding to the received signal, combined with the characteristic that the hit detector channel has continuity, reversely infer the hit detector channel.

[0072] like Figure 2 As shown, this embodiment provides a coding multiplexing method applied to readout of an array-type plastic scintillator detector, and its principle flow mainly includes the following process.

[0073] (1) Design the cross-sectional shape and arrangement of the plastic flash strips in a one-dimensional array, and number them consecutively one by one so that the cross-sectional shape, arrangement and numbering method all meet the principle of continuity of hitting.

[0074] In this embodiment, since the plastic scintillator detector is a type of detector that is easy to process, it can be flexibly processed into a required shape and size within a certain range according to demand.

[0075] In this embodiment, when designing the cross-sectional shape, arrangement and numbering of the plastic flash strips, under the requirement of ensuring that one particle hits multiple adjacent plastic flash strips, the cross-sectional shape of the plastic flash strips can be triangular, stepped, arc-shaped, concave and other cross-sectional shapes, as long as each particle leaves a signal on at least two detection units when passing through the detection device. In this embodiment, a triangular cross-sectional shape is preferred, specifically an isosceles right triangle, such as Figure 3 As shown in the figure, when the cross-sectional shape is triangular, the triangular prism structure of the plastic flash strip can ensure that the particles passing through the detector will not hit only one plastic flash strip. The special cross-sectional structure of the plastic flash strip ensures that each particle will leave a signal on at least two adjacent plastic flash strips. Figure 3 As shown, an isosceles right triangle cross-sectional shape is adopted, and the cross-sectional base of the isosceles right triangle is aligned, and the plastic flash strips are arranged in a zigzag structure along one dimension. In this case, the numbering method is to start from 1 or 0 along the arrangement direction, and number these plastic flash strips in sequence from left to right.

[0076] In this embodiment, the principle of continuity of hitting means that the shape, arrangement and numbering of the plastic flash strips in the designed one-dimensional plastic flash strip array must satisfy that when the particle to be detected hits the detector, it must hit at least two consecutive plastic flash strips, and these plastic flash strips are also continuous in numbering.

[0077] (2) Each plastic flash strip is provided with wavelength-shifting optical fibers at appropriate positions on the cross section. These wavelength-shifting optical fibers will be connected to the photoelectric conversion device and then to the subsequent electronic channels. The detector channel and the signal readout channel are defined according to the signal readout channel multiplexing method, and the electronic channels are also numbered consecutively in a certain order.

[0078] In this embodiment, the wavelength-shifting optical fiber can be coupled to the plastic flash strip by embedding or terminating the entire fiber. The wavelength-shifting optical fiber can be implanted in the plastic flash strip in its entirety, parallel to the plastic flash strip, and the implantation position is generally on the symmetry axis of the plastic flash strip. The specific position needs to be determined based on the simulation results. For example, for a plastic flash strip with an isosceles triangle cross-section, a common implantation method is to open a groove on the bottom surface that is parallel to the plastic flash strip and of equal length, and embed the wavelength-shifting optical fiber therein.

[0079] In this embodiment, the detector channel and the signal readout channel are defined according to the signal readout channel multiplexing method, and the definition method is as follows.

[0080] When the signal readout channel multiplexing method is that multiple wavelength-shifting optical fibers are connected to one photoelectric conversion device, and one photoelectric conversion device is connected to one electronic channel, the channel path from each plastic flash strip to the wavelength-shifting optical fiber is defined as one detector channel, and the subsequent photoelectric conversion device and the electronic channel are defined as one signal readout channel.

[0081] When the signal readout channel multiplexing method is that each wavelength-shifting optical fiber is connected to one photoelectric conversion device, and multiple photoelectric conversion devices are connected to the same subsequent electronic channel, the channel path from each plastic flash strip to the photoelectric conversion device is defined as a detector channel, and the subsequent electronic channel is defined as a signal readout channel.

[0082] It should be noted that, since the plastic flash strips in the one-dimensional array have been numbered when designing their cross-sectional shape, arrangement and numbering, and each plastic flash strip and the wavelength-shifting optical fiber coupled thereto can be regarded as belonging to the same detector channel, the number of the detector channel is the same as the number of the plastic flash strip. In other words, the number of the plastic flash strip is the number of the detector channel. Therefore, only the electronic channel needs to be numbered here, and the number of the signal readout channel is the same as the electronic channel, and then a coding table can be generated to characterize the mapping relationship between the detector channel and the signal readout channel.

[0083] (3) Determine the shortest reuse period by combining the cross-sectional shape of the plastic flash strip with the design of the array arrangement.

[0084] In this embodiment, the shortest multiplexing period refers to the minimum difference between the channel numbers of two detectors connected to the same signal readout channel. When detecting particles, the detection device will turn one side of the detector toward the source of the particles, and detect the light signal through two plastic flash detector units (i.e., plastic flash strips), thereby determining the hitting position. There will be different numbers of plastic flash detector units between each two plastic flash detector units connected to the same photoelectric conversion device. Obviously, if this number is too small, the same particle event may deposit energy in two plastic flash detector units connected to the same photoelectric conversion device, and ultimately make it impossible to distinguish which plastic flash detector units the particle hits. In actual use, the shortest multiplexing period will be judged according to the characteristics of the particles that need to be detected.

[0085] (4) Based on multiple coding constraints such as multiplexing, unique continuity, shortest multiplexing period, multiplexing rate, number of detector channels and number of signal readout channels, a coding table is generated using methods including but not limited to direct generation method and Euler circuit method to represent the mapping relationship between detector channels and signal readout channels.

[0086] In this embodiment, the multiplexing rule refers to that one signal readout channel reads out multiple detector channels. The unique continuity rule refers to that each pair of detector channels with consecutive positions and consecutive numbers is uniquely mapped to a pair of unordered signal readout channels. The multiplexing rate refers to the ratio of the number of detector channels to the number of signal readout channels. The coding table represents the mapping relationship between the detector channel number and the signal readout channel number, and each detector channel is mapped to a signal readout channel.

[0087] In this embodiment, the direct generation method uses a random number generator and coding restrictions to directly generate a random coding table in the program.

[0088] In this embodiment, the Euler circuit method is to construct a simple complete graph with the number of signal readout channels as the number of vertices, wherein these vertices are numbered, and each vertex corresponds to the signal readout channel with the same number. The drawing and numbering of the edges is to start from vertex No. 1, draw an Euler circuit, and number the edges starting from 1 in the order of drawing, and each edge corresponds to the detector channel with the same number. Then, according to the drawing path of the edge, each edge has a starting point, each edge corresponds to its starting point, and the detector channels and signal readouts with corresponding numbers also correspond to each other, and a coding table is generated according to this relationship.

[0089] (5) According to the mapping relationship between the detector channel and the signal readout channel in the coding table, the detector channel is connected to the corresponding signal readout channel to complete the construction of the detection and readout framework.

[0090] In this embodiment, after knowing the one-to-one mapping relationship between the detector channel and the signal readout channel in the coding table, the detector channel can be connected to the corresponding signal readout channel according to the mapping relationship between the detector channel and the signal readout channel in the coding table, so as to realize the pairing connection between the detector channel and the signal readout channel, thereby building a detection readout framework, which serves as the basic framework of the detector for particle detection.

[0091] (6) The constructed detection readout framework is used for particle detection. The hit detector channel is inferred based on the signal readout channel number of the received signal and the certain continuous characteristics of the hit detector channel.

[0092] In this embodiment, since the one-to-one mapping relationship between the detector channel and the signal readout channel is clearly recorded in the coding table, when the detection and readout framework is built and particle detection is performed, the number of the corresponding detector channel can be determined by looking up the number of the received signal readout channel according to the coding table, and the detector channel that was hit can be inferred.

[0093] In this embodiment, according to the different positions where the particles actually hit the plastic flash strip, the information such as the energy deposited in each plastic flash strip will be different, and a more accurate hitting position can be obtained based on this information.

[0094] The principle of the present embodiment of the invention is that after the particles to be tested are injected into the plastic flash strip, they lose energy in the plastic flash strip, causing the atoms and molecules of the plastic flash strip to be excited or ionized, thereby generating light of a certain wavelength. The light is collected and converted into electrical signals by photoelectric conversion devices such as SiPM for subsequent processing. In a specially designed plastic flash strip array, such as an array composed of plastic flash strips with cross-sections designed to be isosceles right triangles, such as Figure 3 As shown, the straight-line trajectory of the particle to be measured must pass through at least two continuous plastic flash strips and deposit energy in them. Based on the principle that the hit plastic flash strips must be continuous, a mapping from the plastic flash strips to the subsequent electronic channels, i.e., a coding table, can be constructed so that each pair of continuous plastic flash strips corresponds to a unique pair of disordered electronic channels, and one electronic channel corresponds to multiple plastic flash strips. According to this mapping, the electronic channels and plastic flash strips are interconnected through wavelength-shifting optical fibers, photoelectric conversion devices and other devices. Then, for a certain electronic channel combination with signal readout, the unique continuous plastic flash strip combination can be inferred to determine the particle hitting position.

[0095] The above mapping also needs to meet a condition: one electronic channel cannot read the signals from two plastic flash strips at the same time, that is, there is a minimum difference between the numbers of each two plastic flash strips read by the same electronic channel, which is called the shortest multiplexing period. This minimum difference is related to the size, cross-sectional shape and arrangement of the plastic flash strips and the physical properties of the particles to be measured.

[0096] There is more than one way to generate a coding table based on the above restrictions, and a coding table can also be constructed based on the Euler circuit in graph theory. According to graph theory knowledge, a circuit that passes through each edge of a graph exactly once is called an Euler circuit, and a graph with an Euler circuit is called an Euler graph. Draw an Euler graph (needs to be a simple graph) according to the path of the Euler circuit, number the edges in the graph in the order of drawing, and correspond one-to-one with the detector channels. In this way, a vertex in the Euler graph can be used as the starting point of multiple edges. Correspondingly, in the coding scheme, a signal readout channel is connected to multiple detector channels (the vertices of the graph are also numbered and correspond one-to-one with the signal readout channels), which satisfies the condition that one signal readout channel corresponds to multiple detector channels. And since each edge in the Euler circuit is only passed once, the starting point and end point of this edge will only be passed continuously once in the path, and this time must correspond to two edges with consecutive numbers. This also means that in this coding scheme, the unordered combination of signal readout channels corresponding to any two consecutive detector channels is unique. In other words, by using the continuity of the detector channels for reading out signals, the number of the detector channels can be uniquely deduced from the combination of the signal reading channels, which satisfies the condition that each pair of continuous plastic flash strips corresponds to a unique pair of disordered electronic channels.

[0097] In order to further demonstrate the implementation method and effect of the encoding scheme, a one-dimensional array type plastic scintillator detector with a certain thickness and strip center distance is set, and the technical solution proposed in this embodiment is used to encode the detector channel.

[0098] In this embodiment, it is assumed that the readout electronics has 7 electronic channels available. The cross-section of the plastic flash strip is designed to be an isosceles right triangle and is arranged in a staggered unidirectional manner. A wavelength-shifting optical fiber is implanted at the center point of each plastic flash strip. Since the plastic flash strip with a cross-section of an isosceles right triangle is used, the implantation position of the wavelength-shifting optical fiber is a suitable position of the symmetry axis of the isosceles right triangle, such as Figure 3 As shown. This array ensures that each particle track must pass through two consecutively arranged plastic flash bars, and the energy deposited by the particle in a plastic flash bar is linearly related to the track distance from the center of the bar. After calculation, when the coding table is generated by the Euler circuit method in this embodiment, if the complete graph coding is used, the signals of 22 detector channels can be read, that is, the signals of 22 plastic scintillators can be read with 7 SiPMs. And assuming that the detected particle will most likely only hit two consecutive plastic flash bars on the designed plastic flash bar array, the shortest multiplexing period is 3.

[0099] The following describes the specific process of coded multiplexing based on a given number of channels. First, a given plastic scintillator with a right-angled triangle cross section embedded in a wavelength-shifted optical fiber is placed according to Figure 3The light signals emitted by each plastic flash strip are led out by a wavelength-shifted optical fiber as a detector channel. At the same time, each electronic channel is connected to a SiPM as a signal readout channel. Then the detector channels and signal readout channels are numbered continuously and non-repeatedly starting from 0. Secondly, 7 points are drawn on the plane for the 7 signal readout channels, and then the Euler circuit is drawn, and each edge is numbered according to the drawing order. Figure 4 As shown, starting from vertex ⑥, ⑥→ →①→⑤→②→④→③→⑥ is the first sub-circuit, ⑥→②→③→①→④→ →⑤→⑥ is the second sub-circuit, ⑥→①→②→ →③→⑤→④→⑥ is the last sub-loop. In this way, a complete Euler graph with 7 vertices is completed, which serves as the coding diagram of this embodiment. The number of each edge is also marked on the edge near the starting point (in order to clearly mark the edges corresponding to the numbers, the numbers are marked on the corresponding edges, and to avoid clutter, only the numbers of some edges are marked). Again, each edge is matched with the starting point when it is drawn, and the corresponding detector channel and signal readout channel are connected accordingly. For example, the starting point of edge 0 is vertex ⑥, and the starting point of edge 1 is vertex , then the signal of plastic flash bar No. 0 is connected to the SiPM of signal readout channel No. 6, and the signal of plastic flash bar No. 1 is connected to the SiPM of signal readout channel No. 0. For another example, the starting points of edge No. 4 and edge No. 8 are both vertex ②, and the signals of plastic flash bar No. 4 and plastic flash bar No. 8 are both connected to the SiPM of signal readout channel No. 2. Figure 5 As shown in FIG. 1 , it is a schematic diagram of connecting some detector channels to 7 electronic channels. For the complete correspondence, see Table 1. Finally, after the signal readout channel receives the event signal, the number of the detector channel can be inferred through the certain continuous characteristics of the hit detector channel. In this embodiment, it is assumed that signal readout channels 2 and 6 receive signals. By comparing Table 1, it can be seen that signal readout channel 2 is connected to plastic flash bars 4, 8, and 16, and signal readout channel 6 is connected to plastic flash bars 0, 7, 14, and 21. The continuous plastic flash bars are 7 and 8, so the cosmic rays hit plastic flash bars 7 and 8.

[0100]

[0101] In view of the problem in the prior art that as the position resolution of an array-type plastic scintillator detector increases, the number of plastic flash bars increases, the number of required signal readout channels increases accordingly, and the complexity and cost of the readout electronics system increases accordingly, this application proposes a coding multiplexing method for reading out an array-type plastic scintillator detector. Without changing the detector structure or reducing the position resolution, the mapping relationship between the detector channel and the signal readout channel is utilized to multiplex the signal readout channels, thereby reducing the number of required signal readout channels and the complexity and cost of the electronics system. At the same time, this application designs the cross-sectional shape, arrangement, and numbering of the plastic flash bars so that when particles are detected, the detectors hit are continuous, which can screen out false events to a certain extent and improve the accuracy of the detector.

[0102] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modifications made within the spirit and principles of the present application, including changes to the specific size, geometry or array structure of the detector (such as changing the cross-sectional shape of the plastic flash strip), or non-creative changes to the way the coding table is generated, as well as equivalent replacements, improvements, etc., should be included in the scope of protection of the present application.

[0103] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0104] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A coding multiplexing method for reading out an array type plastic scintillator detector, characterized in that: The array type plastic scintillator detector comprises a one-dimensional plastic scintillator strip array, the one-dimensional plastic scintillator strip array comprises a plurality of plastic scintillator strips, and the coding multiplexing method applied to the array type plastic scintillator detector readout comprises the following steps: Design the cross-sectional shape, arrangement and numbering of each plastic flash strip in the one-dimensional plastic flash strip array so that the particles to be detected will hit at least two plastic flash strips with consecutive positions and consecutive numbers when hitting the array-type plastic scintillator detector; According to the cross-sectional shape, arrangement and number of each plastic flash strip, the signals of multiple plastic flash strips are merged into one signal readout channel, and the coding parameters based on the detector channel and the signal readout channel are determined; the coding parameters include the shortest multiplexing period, the multiplexing rate, the number of detector channels and the number of signal readout channels, the shortest multiplexing period is the minimum difference between the numbers of two detector channels connected to the same signal readout channel, and the multiplexing rate is the ratio of the number of detector channels to the number of signal readout channels; Generate a coding table according to the coding parameters; the coding table is used to represent the mapping relationship between the detector channel and the signal readout channel; A detection readout framework is established according to the coding table to detect the particles to be detected. The detector channel that was hit is inferred based on the number corresponding to the signal readout channel that received the signal during the detection process.

2. The coding multiplexing method for reading out an array type plastic scintillator detector according to claim 1, characterized in that: Before the step of merging the signals of the plurality of plastic flash strips into one signal readout channel according to the cross-sectional shape, arrangement and number of each plastic flash strip, and determining the coding parameters based on the detector channel and the signal readout channel, the coding multiplexing method applied to the array type plastic scintillator detector readout further includes the following steps: Determine the signal readout channel multiplexing method and define the detector channel and signal readout channel.

3. The coding multiplexing method for reading out an array type plastic scintillator detector according to claim 2, characterized in that: Determine the signal readout channel multiplexing mode and define the detector channel and signal readout channel, specifically including the following steps: For each plastic flash strip, the optical signal generated by the plastic flash strip is derived by direct or indirect derivation, and the signal readout channel is multiplexed; wherein the indirect derivation method is to use a method including whole-strip embedding or termination to couple the wavelength-shifted optical fiber with the plastic flash strip, and derive the optical signal generated by the plastic flash strip to the photoelectric conversion device; the direct derivation method is to directly couple the plastic flash strip with the photoelectric conversion device, and directly detect the optical signal generated by the plastic flash strip; The signal readout channel multiplexing method is a connection method of wavelength-shifted optical fiber coupled with plastic flash strip, photoelectric conversion device and electronic channel, including the following two forms: The first form is that multiple wavelength-shifting optical fibers are connected to a photoelectric conversion device, and a photoelectric conversion device is further connected to an electronic channel; The second form is that each plastic flash strip is coupled to a wavelength-shifting optical fiber and then connected to a photoelectric conversion device, and multiple photoelectric conversion devices are connected to the same subsequent electronic channel; or, the plastic flash strip is directly coupled to the photoelectric conversion device, and multiple photoelectric conversion devices are connected to the same subsequent electronic channel; Based on the signal readout channel multiplexing method, the detector channel and signal readout channel are defined, including the following two methods: The first method is that when the signal readout channel multiplexing method is the first form, the channel path from each plastic flash strip to the wavelength shifting optical fiber is defined as a detector channel, and the subsequent photoelectric conversion device and the electronic channel connected thereto are defined as a signal readout channel; The second method is that when the signal readout channel multiplexing method is the second form, the channel path from each plastic flash strip to the photoelectric conversion device is defined as a detector channel, and the same electronic channel connecting multiple photoelectric conversion devices is defined as a signal readout channel.

4. The coding multiplexing method for reading out an array type plastic scintillator detector according to claim 3, characterized in that: According to the cross-sectional shape, arrangement and number of each plastic flash strip, the signals of multiple plastic flash strips are merged into a signal readout channel, and the coding parameters based on the detector channel and the signal readout channel are determined, which specifically includes the following steps: According to the cross-sectional shape, arrangement and size of the plastic flash strips and the detector area, the number of plastic flash strips is determined, and the number of detector channels is equal to the number of plastic flash strips; According to the number of plastic flash strips and the requirements for multiplexing rate, the signals of multiple plastic flash strips are merged into one signal readout channel, and the number of photoelectric conversion devices and the number of electronic channels are determined; According to the number of photoelectric conversion devices and the number of electronic channels, the electronic channels are numbered to determine the number and number of signal readout channels; The shortest reuse period is determined based on the physical properties of the particles to be tested and the cross-sectional shape, arrangement and numbering of the plastic flash strips.

5. The coding multiplexing method for reading out an array type plastic scintillator detector according to claim 1, characterized in that: Generate a coding table according to the coding parameters, specifically including the following steps: A coding table is generated according to the coding parameters and in combination with coding rules; the coding rules include a multiplexing rule and a unique continuity rule. The multiplexing rule is that one signal readout channel reads out multiple detector channels, and the unique continuity rule is that each pair of detector channels with consecutive positions and consecutive numbers is uniquely mapped to a pair of unordered signal readout channels.

6. The coding multiplexing method for reading out an array type plastic scintillator detector according to claim 1, characterized in that: According to the coding table, a detection readout framework is established to detect the particles to be detected. According to the number corresponding to the signal readout channel receiving the signal during the detection process, the detector channel that was hit is inferred, which specifically includes the following steps: According to the mapping relationship between the detector channel and the signal readout channel in the coding table, the detector channel is connected to the corresponding signal readout channel to form a detection readout framework; The detection readout framework is used to detect the particles to be detected, and the number corresponding to the signal readout channel receiving the signal during the detection process is obtained; According to the number corresponding to the signal readout channel of the received signal and the continuity characteristic of the hit detector channel, the hit detector channel is inferred in reverse.

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