Beam intensity measurement system and method of surface muon beam and storage medium

Abstract

The invention discloses a beam intensity measurement system and method of a surface muon beam and a storage medium, and belongs to the field of beam measurement. The beam intensity measurement system comprises a first detection unit and a second detection unit which are distributed in parallel, so that surface muon beams can pass through the first detection unit and the second detection unit in sequence. And the signal acquisition unit is connected with the first detection unit and the second detection unit and is used for reading pulse signals corresponding to the first detection unit and the second detection unit. The processing unit is connected with the signal acquisition unit and is used for fitting the pulse signals corresponding to the first detection unit and the second detection unit to obtain a first fitting signal and a second fitting signal; determining a signal component of background positron and a signal component of muon based on the first fitting signal and the second fitting signal; and determining the number of background positron and the number of muons based on the first fitting signal, the second fitting signal and the reference charge quantity. According to the invention, the beam intensity of the surface muon beam can be accurately measured, and the content of background positron can be obtained.

Description

Technical Field

[0001] The present invention relates to the field of beam measurement, and in particular to a beam intensity measurement system, method and storage medium for a surface muon beam. Background Art

[0002] The muon beam generated by high-power proton accelerator targeting can be divided into surface muon beam, decay muon beam and cloud muon beam. In the surface muon beam, there are usually a large number of background positrons with the same momentum as the muons. The beam intensity and background positron content of the surface muon beam are key parameters for evaluating the performance of the muon beam. They not only reflect the working status of the beamline equipment, but also provide a reference for the design of the muon beam terminal spectrometer.

[0003] In accelerators, induction methods, such as Faraday cups, are usually used to measure beam intensity, which requires a high beam intensity. However, since the muon beam is a secondary beam, its beam intensity is relatively weak. Therefore, the muon beam cannot be measured using the beam measurement scheme based on the induction method. For the measurement of the intensity of a weak beam, the commonly used technical means is to use a detector with a faster time response to count and measure its signal pulses. However, for a pulse surface muon beam, thousands or even tens of thousands of muons will reach the detector within 100 nanoseconds, which will cause the detector to accumulate and make it impossible to count the signal pulses.

[0004] Therefore, in the prior art, the indirect method is mainly used to measure the beam intensity of the pulsed surface muon beam. This method stops the muon beam through a sample and allows it to decay to produce positrons, and places a positron counter next to the sample. By optimizing the sensitive unit size of the positron counter and the distance between the positron counter and the sample, the signal of the positron counter can be prevented from accumulating, thereby counting and measuring the positrons produced by the muon decay. After that, the relationship between the positron counter and the beam intensity is obtained through Monte Carlo simulation, and the beam intensity of the muon beam is deduced based on the positron counts obtained from the experimental test. The indirect method requires a precise Monte Carlo simulation result when measuring the beam intensity of the pulsed muon beam. However, since the solid angle of the positrons emitted by the positron counter at different positions is different, point muons or uniformly distributed surface muons are usually used as input parameters in the simulation, which may cause the simulation results to deviate from the actual situation, thereby reducing the accuracy of the measured beam intensity. Moreover, since the background positron content will have a direct impact on the experimental results when conducting experiments at the terminal, the indirect measurement method cannot obtain the background positron content in the beam. Therefore, there is an urgent need for a method that can accurately measure the beam intensity of the surface muon beam and obtain the background positron content. Summary of the invention

[0005] The present application provides a surface muon beam intensity measurement system, method and storage medium, which can accurately measure the beam intensity of the surface muon beam and obtain the background positron content. The technical solution is as follows:

[0006] In a first aspect, a system for measuring the beam intensity of a surface muon beam is provided, comprising:

[0007] a first detection unit and a second detection unit, wherein the first detection unit and the second detection unit are arranged in parallel so that a surface muon beam can pass through the first detection unit and the second detection unit in sequence, and the surface muon beam includes background positrons and muons;

[0008] A signal acquisition unit, the signal acquisition unit is connected to the first detection unit and the second detection unit respectively, and the signal acquisition unit is used to read the pulse signals corresponding to the first detection unit and the second detection unit respectively;

[0009] A processing unit, the processing unit is connected to the signal acquisition unit, and the processing unit is used to: acquire multiple pulse signals corresponding to the first detection unit read by the signal acquisition unit, and multiple pulse signals corresponding to the second detection unit read by the signal acquisition unit; fit the multiple pulse signals corresponding to the first detection unit to obtain a first fitting signal; fit the multiple pulse signals corresponding to the second detection unit to obtain a second fitting signal; determine the signal components of background positrons and muons in the surface muon beam based on the first fitting signal and the second fitting signal; determine the number of background positrons and muons in the surface muon beam based on the first fitting signal, the second fitting signal, and a reference charge, wherein the reference charge is obtained based on prior measurements of cosmic rays.

[0010] Optionally, the first detection unit includes a first plastic scintillator and a first photodetector; the first plastic scintillator is optically coupled to the first photodetector, and the first photodetector is used to detect beam particles on the first plastic scintillator;

[0011] The second detection unit includes a second plastic scintillator and a second photodetector; the second plastic scintillator is optically coupled to the second photodetector, and the second photodetector is used to detect beam particles on the second plastic scintillator.

[0012] Optionally, muons in the surface muon beam will stay on the first plastic scintillator due to kinetic energy loss, and the beam particles on the first plastic scintillator detected by the first photodetector include muons, background positrons and Michel electrons, wherein the Michel electrons are generated by the decay of muons and can move to the second plastic scintillator;

[0013] The beam particles on the second plastic scintillator detected by the second photodetector include background positrons and Michel electrons.

[0014] Optionally, the processing unit is specifically configured to:

[0015] determining a signal component of background positrons in the surface muon beam based on the second fitting signal and a signal component of Michel electrons in the second plastic scintillator;

[0016] The signal component of the muons in the surface muon beam is determined based on the first fitting signal, the signal component of the Michel electrons in the first plastic scintillator, and the signal component of the background positrons in the surface muon beam.

[0017] Optionally, the processing unit is specifically configured to:

[0018] Determine the number of background positrons in the surface muon beam based on the second fitting signal, the signal component of the Michel electrons in the second plastic scintillator, and the reference charge amount;

[0019] The number of muons in the surface muon beam is determined based on the first fitting signal, the signal component of the Michel electrons in the first plastic scintillator, the second fitting signal, the signal component of the Michel electrons in the second plastic scintillator, and the reference charge.

[0020] Optionally, the processing unit is specifically configured to:

[0021] Integrating the second fitting signal to obtain a second charge amount;

[0022] integrating the signal components of the Michel electrons in the second plastic scintillator to obtain a third charge amount;

[0023] Based on the second charge amount, the third charge amount, and the reference charge amount, the number of background positrons in the surface muon beam is determined.

[0024] Optionally, the processing unit is specifically configured to:

[0025] Integrating the first fitting signal to obtain a first charge amount;

[0026] Integrating the signal components of the Michel electrons in the first plastic scintillator to obtain a fourth charge amount;

[0027] The number of muons in the surface muon beam is determined based on the first charge amount, the second charge amount, the third charge amount, the fourth charge amount, and the reference charge amount.

[0028] Optionally, the beam intensity measurement system further includes:

[0029] A light shielding unit, wherein the first detection unit and the second detection unit are both located in the light shielding unit; the light shielding unit has a window, and the direction of the window is relative to the end where the surface muon beam is emitted, so that the surface muon beam can reach the first plastic scintillator and the second plastic scintillator;

[0030] A power supply unit is connected to the first photodetector and the second photodetector and is used to supply power to the first photodetector and the second photodetector.

[0031] On the other hand, a method for measuring the beam intensity of a surface muon beam is provided, which is applied to a processing unit in a beam intensity measurement system for a surface muon beam, wherein the beam intensity measurement system comprises a first detection unit and a second detection unit arranged in parallel so that the surface muon beam can pass through in sequence; the method comprises:

[0032] Acquire a plurality of pulse signals corresponding to the first detection unit and a plurality of pulse signals corresponding to the second detection unit;

[0033] Fitting a plurality of pulse signals corresponding to the first detection unit to obtain a first fitting signal;

[0034] Fitting a plurality of pulse signals corresponding to the second detection unit to obtain a second fitting signal;

[0035] Determine a signal component of background positrons and a signal component of muons in the surface muon beam based on the first fitting signal and the second fitting signal;

[0036] The number of background positrons and the number of muons in the surface muon beam are determined based on the first fitting signal, the second fitting signal, and a reference charge, wherein the reference charge is obtained based on a prior measurement of cosmic rays.

[0037] On the other hand, a computer-readable storage medium is provided, on which a computer program is stored, and the computer program is executed by a processor to implement the steps of the above-mentioned method for measuring the beam intensity of a surface muon beam.

[0038] On the other hand, a computer program product is provided, which includes a computer program and / or instructions, and when the computer program and / or instructions are executed by a processor, the steps of the above-mentioned method for measuring the beam intensity of a surface muon beam are implemented.

[0039] The technical solution provided by the embodiments of the present application can at least bring the following beneficial effects:

[0040] The beam intensity measurement system of the surface muon beam in the embodiment of the present application includes a first detection unit and a second detection unit, and the surface muon beam can pass through the first detection unit and the second detection unit in sequence, so that the signal acquisition unit can obtain multiple pulse signals corresponding to the first detection unit and the multiple pulse signals corresponding to the second detection unit, and fit them respectively to obtain a first fitting signal and a second fitting signal, which can improve the accuracy of the subsequent measurement process, that is, to obtain accurate signal components of background positrons, signal components of muons, the number of background positrons and the number of muons in the surface muon beam, and improve the accuracy of measuring the beam intensity of the surface muon beam. It can be seen that the technical solution provided in the embodiment of the present application can not only accurately measure the beam intensity of the surface muon beam, but also obtain the background positron content. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of the structure of a surface muon beam intensity measurement system provided in an embodiment of the present application;

[0042] Figure 2 A schematic structural diagram of another surface muon beam intensity measurement system provided in an embodiment of the present application;

[0043] Figure 3 A schematic diagram of the structure of another surface muon beam intensity measurement system provided in an embodiment of the present application;

[0044] Figure 4 A flow chart of a method for measuring the beam intensity of a surface muon beam provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are for making the present application better understood. However, those skilled in the art can easily recognize that some features can be omitted in different situations, or can be replaced by other elements, materials, methods. In some cases, some operations related to the present application are not shown or described in the specification, this is to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0046] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0047] The serial numbers of the components in this document, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0048] Before explaining in detail the beam intensity measurement system and beam intensity measurement method of the surface muon beam provided in the embodiments of the present application, the terms involved in the embodiments of the present application are first explained.

[0049] Muon: Muon in English, also known as μon, has a mass between proton and electron, and the half-life of muon is 2.2 microseconds.

[0050] Beam intensity: Beam intensity refers to the density of particle flow per unit area of ​​a particle beam passing through a certain point per unit time. In the fields of particle physics and accelerator physics, beam intensity is an important physical quantity, which is directly related to the acceleration, transmission and interaction of particle beams with matter.

[0051] Plastic scintillator: It is a solid solution of organic scintillating material in plastic. It can be used to detect α, β, γ, fast neutrons, protons, cosmic rays and fission fragments. It is easy to process into various shapes and has the advantages of non-deliquescent, stable performance, radiation resistance, short scintillation decay time and low price.

[0052] Cosmic rays: A stream of high-energy particles from outer space, mainly composed of protons, alpha particles (helium nuclei) and other heavy nuclei, as well as a small amount of electrons and antimatter particles such as positrons and antiprotons. Cosmic rays are ejected through the atmosphere, and the main particles that reach the earth's surface are muons and electrons.

[0053] Next, the beam intensity measurement system of the surface muon beam provided in the embodiment of the present application is introduced in detail.

[0054] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a beam intensity measurement system provided in an embodiment of the present application. Please refer to Figure 1The beam intensity measurement system includes a first detection unit 1, a second detection unit 2, a signal acquisition unit 3 and a processing unit 4. The first detection unit 1 and the second detection unit 2 are arranged in parallel so that the surface muon beam can pass through the first detection unit 1 and the second detection unit 2 in sequence, and the surface muon beam includes background positrons and muons; the signal acquisition unit 3 is connected to the first detection unit 1 and the second detection unit 2 respectively, and the signal acquisition unit 3 is used to read the pulse signals corresponding to the first detection unit 1 and the second detection unit 2 respectively; the processing unit 4 is connected to the signal acquisition unit 3, and is used to obtain multiple pulse signals corresponding to the first detection unit 1 read by the signal acquisition unit 3, and multiple pulse signals corresponding to the second detection unit 2 read by the signal acquisition unit 3, and fit the multiple pulse signals corresponding to the first detection unit 1 to obtain a first fitting signal, and fit the multiple pulse signals corresponding to the second detection unit 2 to obtain a second fitting signal, and then, based on the first fitting signal and the second fitting signal, determine the signal components of the background positrons and the signal components of the muons in the surface muon beam, and then, based on the first fitting signal, the second fitting signal, and the reference charge, determine the number of background positrons and the number of muons in the surface muon beam, and the reference charge is obtained based on the cosmic ray measurement in advance.

[0055] from Figure 1 It can be seen that since the first detection unit 1 and the second detection unit 2 are distributed in parallel, and the surface muon beam is emitted from the side close to the first detection unit 1, after the surface muon beam is emitted, the surface muon beam can pass through the first detection unit 1 and the second detection unit 2 in sequence.

[0056] The signal acquisition unit 3 is connected to the first detection unit 1, so when the surface muon beam passes through the first detection unit 1, the signal acquisition unit 3 can read the pulse signal corresponding to the first detection unit 1; similarly, the signal acquisition unit 3 is also connected to the second detection unit 2, so when the surface muon beam passes through the second detection unit 2, the signal acquisition unit 3 can read the pulse signal corresponding to the second detection unit 2.

[0057] It should be noted that the signal acquisition unit 3 can be a high-precision waveform sampling and reading electronic system, so that the accuracy of the read pulse signal can be improved. Alternatively, in application, the signal acquisition unit 3 can also be other signal acquisition devices, which is not limited in the embodiment of the present application.

[0058] The processing unit 4 is connected to the signal acquisition unit 3, so that after the signal acquisition unit 3 reads the pulse signals corresponding to the first detection unit 1 and the second detection unit 2, the signal acquisition unit 3 can send the read pulse signals to the processing unit 4, so that the processing unit 4 performs subsequent operations based on the received pulse signals.

[0059] In some embodiments, in order to improve the accuracy of the measured beam intensity of the surface muon beam, multiple surface muon beams to be measured can be emitted, so that the surface muon beam to be measured will pass through the first detection unit 1 and the second detection unit 2 multiple times, so that the signal acquisition unit 3 reads multiple pulse signals corresponding to the first detection unit 1 and multiple pulse signals corresponding to the second detection unit 2. In this way, the processing unit 4 can obtain multiple pulse signals corresponding to the first detection unit 1, and fit the multiple pulse signals to obtain the first fitting signal corresponding to the first detection unit 1; similarly, the processing unit 4 can also obtain multiple pulse signals corresponding to the second detection unit 2, and fit the multiple pulse signals to obtain the second fitting signal corresponding to the second detection unit 2.

[0060] In addition, in some embodiments, the processing unit 4 can determine a relatively stable section of the multiple pulse signals corresponding to the first detection unit 1 as a fitting interval to obtain a first fitting signal based on the fitting interval; similarly, the processing unit 4 can also determine a relatively stable section of the multiple pulse signals corresponding to the second detection unit 2 as a fitting interval to obtain a second fitting signal based on the fitting interval.

[0061] After obtaining the first fitting signal and the second fitting signal, the processing unit 4 can determine the signal components of background positrons and muons in the surface muon beam based on the first fitting signal and the second fitting signal; then, it can also determine the number of background positrons and muons based on the first fitting signal, the second fitting signal and the reference charge. In this way, the beam intensity of the surface muon beam can be accurately measured, and the content of background positrons can be obtained.

[0062] In some embodiments, the reference charge is obtained based on the cosmic ray measured in advance. When the first detection unit 1 and the second detection unit 2 are the same and have the same working voltage, the cosmic ray particles are allowed to pass through the first detection unit 1 and the second detection unit 2 in sequence in advance, and the signals of the cosmic rays corresponding to the first detection unit 1 and the second detection unit 2 acquired by the signal acquisition unit 3 are the same, so that the signal acquisition unit 3 can acquire the signal of the cosmic ray and send the signal of the cosmic ray to the processing unit 4, and then the signal processing unit 4 can integrate the signal of the cosmic ray to obtain the reference charge. After obtaining the reference charge, the processing unit 4 can store the reference charge so that in the subsequent process, relevant calculations can be performed based on the reference charge.

[0063] In some embodiments, please refer to Figure 2The first detection unit 1 includes a first plastic scintillator 11 and a first photodetector 12; the first plastic scintillator 11 is optically coupled with the first photodetector 12, and the first photodetector 12 is used to detect beam particles on the first plastic scintillator 11; the second detection unit 2 includes a second plastic scintillator 21 and a second photodetector 22; the second plastic scintillator 21 is optically coupled with the second photodetector 22, and the second photodetector 22 is used to detect beam particles on the second plastic scintillator 21.

[0064] The parameters of the first plastic scintillator 11 and the second plastic scintillator 21 are the same, and the sizes of the two should be able to cover the beam spot to avoid the situation where the beam spot is not covered and the subsequent measurement results are affected. For example, the length and width of the first plastic scintillator 11 and the second plastic scintillator 21 are both 150 mm. In addition, the relevant parameters of the first photodetector 12 and the second photodetector 22 should also be the same.

[0065] In addition, in some embodiments, in order to improve the light collection efficiency of the first photodetector 12 and the second photodetector 22, a reflective layer can be wrapped around the periphery of the first plastic scintillator 11 and the second plastic scintillator 21, and silicone grease can be used to optically couple the first plastic scintillator 11 and the first photodetector 12, and silicone grease can be used to optically couple the second plastic scintillator 21 and the second photodetector 22.

[0066] It should be noted that the first photodetector 12 and the second photodetector 22 may be PMTs (Photomultipliers), which are special vacuum tubes that are sensitive to ultraviolet light, visible light, and near-infrared light, and can enhance incoming optical signals so that the optical signals can be measured. Alternatively, in applications, the first photodetector 12 and the second photodetector 22 may also be other components. The above is illustrated by using silicone grease to optically couple the plastic scintillator and the photodetector. Alternatively, in applications, the plastic scintillator and the photodetector may also be optically coupled in other ways. In other words, the embodiments of the present application do not limit the type of photodetector and the optical coupling method.

[0067] In some embodiments, muons will stay in the first plastic scintillator 11 due to kinetic energy loss, and the beam particles on the first plastic scintillator 11 detected by the first photodetector 12 include muons, background positrons and Michel electrons. Michel electrons are generated by the decay of muons and can move to the second plastic scintillator 21; the beam particles on the second plastic scintillator 21 detected by the second photodetector 22 include background positrons and Michel electrons.

[0068] That is to say, since the surface muon beam includes muons, the muons therein will remain in the first plastic scintillator 11 due to the loss of all kinetic energy in the ionization process and will not reach the second plastic scintillator 21. Therefore, the beam particles on the first plastic scintillator 11 detected by the first photodetector 12 include muons, while the beam particles on the second plastic scintillator 21 detected by the second photodetector 22 will not include muons.

[0069] In addition, since the background positrons in the surface muon beam can be approximated as the minimum ionized particles, they have a relatively strong penetrating ability and will pass through the first plastic scintillator 11 and the second plastic scintillator 21, and deposit part of their energy in the first plastic scintillator 11 and the second plastic scintillator 21. Therefore, the beam particles on the first plastic scintillator 11 detected by the first photodetector 12 will include the background positrons, and the beam particles on the second plastic scintillator 21 detected by the second photodetector 22 will also include the background positrons.

[0070] Since the half-life of a muon is 2.2 microseconds, the muons staying in the first plastic scintillator 11 will decay to generate Michel electrons, and the movement direction of the Michel electrons is random, so that energy deposition will also occur in the first plastic scintillator 11 and the second plastic scintillator 21. Therefore, the beam particles on the first plastic scintillator 11 detected by the first photodetector 12 will include Michel electrons, and the beam particles on the second plastic scintillator 21 detected by the second photodetector 22 will also include Michel electrons.

[0071] It should be noted that the thickness of the first plastic scintillator 11 and the second plastic scintillator 21 should be able to ensure that muons can stay inside the first plastic scintillator 11 and allow background positrons to pass through. For example, the thickness of the first plastic scintillator 11 and the second plastic scintillator 21 are both 10 mm. The embodiment of the present application does not limit the thickness of the first plastic scintillator 11 and the second plastic scintillator 21.

[0072] Continuing with the above description, the energy deposited in the first plastic scintillator 11 will be converted into photons and transmitted to the first photodetector 12, thereby, the signal acquisition unit 3 can obtain the pulse signal corresponding to the first detection unit 1; similarly, the energy deposited in the second plastic scintillator 21 will also be converted into photons and transmitted to the second photodetector 22, thereby, the signal acquisition unit 3 can obtain the pulse signal corresponding to the second detection unit 2.

[0073] In some embodiments, the processing unit 4 can determine the signal component of background positrons based on the second fitting signal and the signal component of Michel electrons in the second plastic scintillator 21; and determine the signal component of muons based on the first fitting signal, the signal component of Michel electrons in the first plastic scintillator 11, and the signal component of background positrons.

[0074] Based on the above description, it can be known that the beam particles on the first plastic scintillator 11 include muons, background positrons and Michel electrons, and the beam particles on the second plastic scintillator 21 include background positrons and Michel electrons. Therefore, the first fitting signal includes the signal component of muons, the signal component of background positrons and the signal component of Michel electrons, and the second fitting signal includes the signal component of background positrons and the signal component of Michel electrons. The signal component of Michel electrons can be directly obtained based on the normalization function and the exponential decay function corresponding to the second fitting signal, and the exponential decay function corresponding to the second fitting signal can be directly obtained based on the second fitting signal, that is, the signal component of Michel electrons in the second plastic scintillator 21 can be directly obtained. Therefore, the signal component of background positrons in the surface muon beam can be determined by subtracting the signal component of Michel electrons in the second plastic scintillator 21 from the second fitting signal.

[0075] As an example, the signal component of the Michel electrons in the second plastic scintillator 21 can be expressed according to the following formula (1):

[0076] f M2 (T) = f Beam (t)*f 2D (t) (1)

[0077] Among them, f M2 (T) represents the signal component of the Michel electrons in the second plastic scintillator 21, f Beam (t) represents the normalization function, f 2D (t) represents the exponential decay function corresponding to the second fitting signal.

[0078] Then, the signal component of background positrons in the surface muon beam can be expressed as follows:

[0079]

[0080] in, represents the signal component of background positrons, and f2(t) represents the second fitting signal.

[0081] Since the background positrons can be approximately considered as the smallest ions, their energy deposition in the first plastic scintillator 11 is close to that in the second plastic scintillator 21, and the signal components of the Michel electrons in the first plastic scintillator 11 are similar to those in the second plastic scintillator 21, and can also be directly obtained. Therefore, the signal components of the muons in the surface muon beam can be determined by subtracting the signal components of the Michel electrons in the first plastic scintillator 11 from the first fitting signal and then subtracting the signal components of the background positrons in the second fitting signal.

[0082] Continuing with the above example, the signal component of the Michel electrons in the first plastic scintillator 11 is similar to the signal component of the Michel electrons in the second plastic scintillator 21 and can be expressed according to the following formula (3):

[0083] f M1 (t) = f Beam (t) * f 1D (t) (3)

[0084] Among them, f M1 (t) represents the signal component of the Michel electrons in the first plastic scintillator 11, and f 1D (t) represents the exponential decay function corresponding to the first fitting signal.

[0085] Then, the signal component of muons in the surface muon beam can be expressed as follows:

[0086]

[0087] in, represents the signal component of the muon, and f1(t) represents the first fitting signal.

[0088] In some embodiments, the processing unit 4 can also determine the number of background positrons based on the second fitting signal, the signal component of the Michel electrons in the second plastic scintillator 21, and the reference charge, and determine the number of muons based on the first fitting signal, the signal component of the Michel electrons in the first plastic scintillator 11, the second fitting signal, the signal component of the Michel electrons in the second plastic scintillator 21, and the reference charge.

[0089] Based on the above description, it can be known that the second fitting signal includes the signal component of the background positrons and the signal component of the Michel electrons, and the signal component of the Michel electrons can be directly obtained, and the reference charge is obtained in advance, so the number of background positrons can be determined first. Moreover, the energy deposition of the background positrons in the first plastic scintillator 11 is close to the energy deposition in the second plastic scintillator 21, so after determining the number of background positrons corresponding to the second fitting signal, it is considered that the number of background positrons corresponding to the first fitting signal is the same as the number of background positrons corresponding to the second fitting signal, and thus, based on the number of background positrons corresponding to the second fitting signal, the first fitting signal, the signal component of the Michel electrons in the first plastic scintillator 11, and the reference charge, the number of muons is determined.

[0090] In some embodiments, the processing unit 4 may determine the number of background positrons according to the following steps (1)-(3).

[0091] (1) Integrate the second fitting signal to obtain a second charge quantity.

[0092] Based on the above description, it can be seen that the signal components of the second fitting signal include the signal components of the background positrons and the signal components of the Michel electrons. Therefore, after integrating the second fitting signal, the second charge obtained includes the charge of the background positrons and the charge of the Michel electrons in the second plastic scintillator 21.

[0093] (2) Integrate the signal components of the Michel electrons in the second plastic scintillator 21 to obtain a third charge amount.

[0094] Continuing with the above description, since the signal component of the Michel electrons in the second plastic scintillator 21 can be directly obtained, after integrating it, the charge amount of the Michel electrons in the second plastic scintillator 21, that is, the third charge amount, can be obtained.

[0095] (3) Determine the number of background positrons based on the second charge, the third charge, and the reference charge.

[0096] Since the second charge is equal to the sum of the charge of the background positrons and the third charge, the charge of the background positrons can be obtained by subtracting the third charge from the second charge. Furthermore, since cosmic rays are approximately minimum ionized particles, their energy deposition in the second plastic scintillator 21 is consistent with the energy deposition of the background positrons in the second plastic scintillator 21. Therefore, the charge of the background positrons needs to be divided by the reference charge to obtain the number of background positrons.

[0097] As an example, the number of background positrons may be determined according to the following formula (5):

[0098]

[0099] in, represents the number of background positrons, Q 2T represents the second charge, Q 2M represents the third charge, Q c Indicates the reference charge.

[0100] In some embodiments, the processing unit 4 may also determine the number of muons according to the following steps (1)-(3).

[0101] (1) Integrate the first fitting signal to obtain a first charge amount.

[0102] Based on the above description, it can be seen that the signal components of the first fitting signal include the signal components of muons, the signal components of background positrons and the signal components of Michel electrons. Therefore, after integrating the first fitting signal, the first charge obtained includes the charge of muons, the charge of background positrons and the charge of Michel electrons in the first plastic scintillator 11.

[0103] (2) Integrate the signal components of the Michel electrons in the first plastic scintillator 11 to obtain a fourth charge amount.

[0104] Continuing with the above description, since the signal component of the Michel electrons in the first plastic scintillator 11 can be directly obtained, after integrating it, the charge amount of the Michel electrons in the first plastic scintillator 11, that is, the fourth charge amount, can be obtained.

[0105] (3) Determine the number of muons based on the first charge amount, the second charge amount, the third charge amount, the fourth charge amount, and the reference charge amount.

[0106] Since the energy deposition of the background positrons in the first plastic scintillator 11 is close to the energy deposition in the second plastic scintillator 21 , the charge amount of the background positrons in the first charge amount is the same as the charge amount of the background positrons in the second charge amount, which is equal to the second charge amount minus the third charge amount.

[0107] Moreover, the first charge is equal to the sum of the charge of the muon, the charge of the background positron and the fourth charge, so the charge of the muon can be obtained by subtracting the charge of the background positron from the first charge and then subtracting the fourth charge. Moreover, since cosmic rays are approximately the minimum ionized particles, and the energy deposition of the muon in the first plastic scintillator 11 is twice the energy deposition of the cosmic ray in the first plastic scintillator 11, it is necessary to divide the charge of the muon by twice the reference charge to obtain the number of muons.

[0108] As an example, the number of background positrons may be determined according to the following formula (6):

[0109]

[0110] in, represents the number of muons, Q 1T represents the first charge, Q 1M represents the fourth charge, represents the number of background positrons, Q 2T represents the second charge, Q 2M represents the third charge, Q c Indicates the reference charge.

[0111] In some embodiments, please refer to Figure 3 The beam intensity measurement system further includes a shading unit 5 and a power supply unit 6. The first detection unit 1 and the second detection unit 2 are both located in the shading unit 5; the shading unit 5 has a window 51, and the direction of the window 51 is opposite to the end where the surface muon beam is emitted, so that the surface muon beam can reach the first plastic scintillator 11 and the second plastic scintillator 21. The power supply unit 6 is connected to the first photodetector 12 and the second photodetector 22, and is used to supply power to the first photodetector 12 and the second photodetector 22.

[0112] In order to prevent other photoelectrons in the environment from affecting the measurement result of the beam current measurement system, the beam current intensity measurement system may further include a shading unit 5 , and the shading unit 5 may surround the first detection unit 1 and the second detection unit 2 .

[0113] Furthermore, in order to allow the surface muon beam to reach the first plastic scintillator 11 and the second plastic scintillator 21, the shading unit 5 may further have a window 51 on the side close to where the surface muon beam is emitted. Furthermore, the window 51 may further have aluminum foil for shielding, thereby preventing other photoelectrons in the environment from affecting the measurement results.

[0114] It should be noted that the shading unit 5 may be a light-proof dark box, or other components capable of shading. The power supply unit 6 may be a high-voltage system, or other power supply systems. This embodiment of the application does not limit this.

[0115] The beam intensity measurement system of the surface muon beam in the embodiment of the present application includes a first detection unit and a second detection unit, and the surface muon beam can pass through the first detection unit and the second detection unit in sequence, so that the signal acquisition unit can obtain multiple pulse signals corresponding to the first detection unit and multiple pulse signals corresponding to the second detection unit, and fit them respectively to obtain a first fitting signal and a second fitting signal, which can improve the accuracy of the subsequent measurement process, that is, to obtain accurate signal components of background positrons, signal components of muons, the number of background positrons and the number of muons in the surface muon beam, and improve the accuracy of measuring the beam intensity of the surface muon beam. Moreover, the beam intensity measurement system also includes a shading unit, and the first detection unit and the second detection unit are both located in the shading unit, which can avoid other photoelectrons in the environment from affecting the first detection unit and the second detection unit, and further improve the accuracy of measuring the beam intensity of the surface muon beam. In summary, the beam intensity measurement system of the surface muon beam provided in the embodiment of the present application can not only accurately measure the beam intensity of the surface muon beam, but also obtain the background positron content.

[0116] Next, the method for measuring the beam intensity of a surface muon beam provided in an embodiment of the present application is explained in detail.

[0117] Figure 4 This is a flow chart of a method for measuring the beam intensity of a surface muon beam provided in an embodiment of the present application. The method is applied to a processing unit in a beam intensity measurement system for a surface muon beam. The beam intensity measurement system includes a first detection unit and a second detection unit arranged in parallel so that the surface muon beam emitted by the beam intensity measurement system can pass through in sequence. Please refer to Figure 4 , the method comprises the following steps:

[0118] Step 401: Acquire multiple pulse signals corresponding to the first detection unit and multiple pulse signals corresponding to the second detection unit.

[0119] The process of the above step 401 has been described in detail above. Please refer to the above related content and will not be repeated here.

[0120] Step 402: Fitting a plurality of pulse signals corresponding to the first detection unit to obtain a first fitting signal.

[0121] The process of the above step 402 has been described in detail above. Please refer to the relevant content above and will not be repeated here.

[0122] Step 403: Fitting multiple pulse signals corresponding to the second detection unit to obtain a second fitting signal.

[0123] The process of the above step 403 has been described in detail above. Please refer to the above related content and will not be repeated here.

[0124] Step 404: Determine the signal components of background positrons and muons in the surface muon beam based on the first fitting signal and the second fitting signal.

[0125] The process of the above step 404 has been described in detail above. Please refer to the relevant content above and will not be repeated here.

[0126] Step 405: Determine the number of background positrons and muons in the surface muon beam based on the first fitting signal, the second fitting signal, and a reference charge, wherein the reference charge is obtained based on a prior measurement of cosmic rays.

[0127] The process of the above step 405 has been described in detail above. Please refer to the above related content and will not be repeated here.

[0128] In the embodiment of the present application, by fitting the multiple pulse signals corresponding to the first detection unit and the multiple pulse signals corresponding to the second detection unit, the first fitting signal and the second fitting signal are obtained, which can improve the accuracy of the subsequent measurement process, that is, the accurate signal components of background positrons, signal components of muons, the number of background positrons and the number of muons in the surface muon beam are obtained. It can be seen that the method provided in the embodiment of the present application can not only accurately measure the beam intensity of the surface muon beam, but also obtain the background positron content.

[0129] Those skilled in the art will appreciate that all or part of the functions of the various methods in the above-mentioned embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can be stored in a computer-readable storage medium, and the storage medium can include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to implement the above-mentioned functions. For example, the program is stored in the memory of the device, and when the program in the memory is executed by the processor, all or part of the above-mentioned functions can be implemented. In addition, when all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can also be stored in a storage medium such as a server, another computer, disk, optical disk, flash disk or mobile hard disk, and can be downloaded or copied and saved in the memory of the local device, or the system of the local device is updated, and when the program in the memory is executed by the processor, all or part of the functions in the above-mentioned embodiments can be implemented.

[0130] The above specific examples are used to illustrate the present invention, which are only used to help understand the present invention and are not used to limit the present invention. For those skilled in the art to which the present invention belongs, some simple deductions, modifications or substitutions can be made according to the idea of ​​the present invention.

Claims

1. A surface muon beam intensity measurement system, characterized in that: include: a first detection unit and a second detection unit, wherein the first detection unit and the second detection unit are arranged in parallel so that a surface muon beam can pass through the first detection unit and the second detection unit in sequence, and the surface muon beam includes background positrons and muons; A signal acquisition unit, the signal acquisition unit is connected to the first detection unit and the second detection unit respectively, and the signal acquisition unit is used to read the pulse signals corresponding to the first detection unit and the second detection unit respectively; A processing unit, the processing unit is connected to the signal acquisition unit, and the processing unit is used to: acquire a plurality of pulse signals corresponding to the first detection unit read by the signal acquisition unit, and a plurality of pulse signals corresponding to the second detection unit read by the signal acquisition unit; Fitting a plurality of pulse signals corresponding to the first detection unit to obtain a first fitting signal; Fitting multiple pulse signals corresponding to the second detection unit to obtain a second fitting signal; determining the signal components of background positrons and muons in the surface muon beam based on the first fitting signal and the second fitting signal; determining the number of background positrons and muons in the surface muon beam based on the first fitting signal, the second fitting signal, and a reference charge, wherein the reference charge is obtained based on prior measurements of cosmic rays.

2. The surface muon beam intensity measurement system according to claim 1, characterized in that: The first detection unit includes a first plastic scintillator and a first photodetector; The first plastic scintillator is optically coupled to the first photodetector, and the first photodetector is used to detect beam particles on the first plastic scintillator; The second detection unit includes a second plastic scintillator and a second photodetector; The second plastic scintillator is optically coupled to the second photodetector, and the second photodetector is used to detect beam particles on the second plastic scintillator.

3. The surface muon beam intensity measurement system according to claim 2, characterized in that: The muons in the surface muon beam will stay on the first plastic scintillator due to kinetic energy loss, and the beam particles on the first plastic scintillator detected by the first photodetector include muons, background positrons and Michel electrons, and the Michel electrons are generated by the decay of muons and can move to the second plastic scintillator; The beam particles on the second plastic scintillator detected by the second photodetector include background positrons and Michel electrons.

4. The surface muon beam intensity measurement system according to claim 3, characterized in that: The processing unit is specifically used for: determining a signal component of background positrons in the surface muon beam based on the second fitting signal and a signal component of Michel electrons in the second plastic scintillator; The signal component of the muons in the surface muon beam is determined based on the first fitting signal, the signal component of the Michel electrons in the first plastic scintillator, and the signal component of the background positrons in the surface muon beam.

5. The surface muon beam intensity measurement system according to claim 4, characterized in that: The processing unit is specifically used for: Determine the number of background positrons in the surface muon beam based on the second fitting signal, the signal component of the Michel electrons in the second plastic scintillator, and the reference charge amount; The number of muons in the surface muon beam is determined based on the first fitting signal, the signal component of the Michel electrons in the first plastic scintillator, the second fitting signal, the signal component of the Michel electrons in the second plastic scintillator, and the reference charge.

6. The surface muon beam intensity measurement system according to claim 5, characterized in that: The processing unit is specifically used for: Integrating the second fitting signal to obtain a second charge amount; integrating the signal components of the Michel electrons in the second plastic scintillator to obtain a third charge amount; Based on the second charge amount, the third charge amount, and the reference charge amount, the number of background positrons in the surface muon beam is determined.

7. The surface muon beam intensity measurement system according to claim 5 or 6, characterized in that: The processing unit is specifically used for: Integrating the first fitting signal to obtain a first charge amount; Integrating the signal components of the Michel electrons in the first plastic scintillator to obtain a fourth charge amount; The number of muons in the surface muon beam is determined based on the first charge amount, the second charge amount, the third charge amount, the fourth charge amount, and the reference charge amount.

8. The system for measuring the beam intensity of a surface muon beam according to any one of claims 1 to 2, characterized in that: The beam intensity measurement system also includes: A light shielding unit, wherein the first detection unit and the second detection unit are both located in the light shielding unit; the light shielding unit has a window, and the direction of the window is relative to the end where the surface muon beam is emitted, so that the surface muon beam can reach the first plastic scintillator and the second plastic scintillator; A power supply unit is connected to the first photodetector and the second photodetector and is used to supply power to the first photodetector and the second photodetector.

9. A method for measuring the beam intensity of a surface muon beam, applied to a processing unit in a beam intensity measurement system for a surface muon beam, wherein the beam intensity measurement system comprises a first detection unit and a second detection unit arranged in parallel so that the surface muon beam can pass through in sequence; the method comprises: Acquire a plurality of pulse signals corresponding to the first detection unit and a plurality of pulse signals corresponding to the second detection unit; Fitting a plurality of pulse signals corresponding to the first detection unit to obtain a first fitting signal; Fitting a plurality of pulse signals corresponding to the second detection unit to obtain a second fitting signal; Determine a signal component of background positrons and a signal component of muons in the surface muon beam based on the first fitting signal and the second fitting signal; The number of background positrons and the number of muons in the surface muon beam are determined based on the first fitting signal, the second fitting signal, and a reference charge, wherein the reference charge is obtained based on a prior measurement of cosmic rays.

10. A computer-readable storage medium, characterized in that: The medium stores a computer program, which can be executed by a processor to implement the method according to claim 9.

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