WO2020088067A1 - 重建粒子径迹的方法和设备、以及检查方法和检查设备 - Google Patents

重建粒子径迹的方法和设备、以及检查方法和检查设备 Download PDF

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Publication number
WO2020088067A1
WO2020088067A1 PCT/CN2019/103057 CN2019103057W WO2020088067A1 WO 2020088067 A1 WO2020088067 A1 WO 2020088067A1 CN 2019103057 W CN2019103057 W CN 2019103057W WO 2020088067 A1 WO2020088067 A1 WO 2020088067A1
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Prior art keywords
drift
cosmic ray
particles
incident
scintillator
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PCT/CN2019/103057
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English (en)
French (fr)
Inventor
于昊
刘必成
易茜
王永强
曾鸣
宫辉
李荐民
孙尚民
李元景
陈志强
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同方威视技术股份有限公司
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Publication of WO2020088067A1 publication Critical patent/WO2020088067A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V5/00—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity
    • G01V5/20—Detecting prohibited goods, e.g. weapons, explosives, hazardous substances, contraband or smuggled objects
    • G01V5/22—Active interrogation, i.e. by irradiating objects or goods using external radiation sources, e.g. using gamma rays or cosmic rays
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/06—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and measuring the absorption
    • G01N23/10—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and measuring the absorption the material being confined in a container, e.g. in a luggage X-ray scanners

Definitions

  • the present disclosure relates to radiation detection technology, and in particular, to a method and apparatus for reconstructing the tracks of cosmic ray particles, and an apparatus and method for inspecting an inspected object such as a container truck.
  • Cosmic ray imaging technology uses natural cosmic rays as a radiation source, has strong penetrating power, and has no extraneous radiation. It has been proven to be used in the inspection of high atomic number materials such as nuclear fuel, nuclear waste, shields, drugs, explosives, etc. -Low atomic number materials.
  • the key to cosmic ray inspection and material identification lies in the track reconstruction method of cosmic ray particles.
  • the current track reconstruction method mainly obtains the optimal solution through linear fitting and iterative algorithm, and the initial value of iteration is selected by experience. This track reconstruction method relies too much on experience. When the initial value deviates a lot or the drift tube performance difference is large, a large error will occur, and the positioning accuracy and reconstruction effect are poor.
  • a method for reconstructing the tracks of cosmic ray particles includes the following steps:
  • a cosmic ray particle detector is used to detect cosmic ray particles.
  • the cosmic ray particle detector includes at least one scintillator and a plurality of drift tubes. The charged particles in the drift tube drift;
  • the track of the cosmic ray particles is fitted.
  • the method may further include:
  • calculating the drift time of the charged particles in the at least two drift tubes according to the time zero includes:
  • the step of using the at least one scintillator to record the time zero point at which the cosmic ray particles are incident on the cosmic ray particle detector includes:
  • the method further includes using the at least one scintillator to measure the position where the cosmic ray particles are incident on the scintillator,
  • the step of fitting the tracks of the cosmic ray particles according to the determined positions of the cosmic ray particles incident on the at least two drift tubes includes:
  • the track of the cosmic ray particles is fitted.
  • the step of determining the position where the cosmic ray particles are incident on the at least two drift tubes based on the calculated drift time includes:
  • the position where the cosmic ray particles are incident on the at least two drift tubes is determined.
  • the method further includes: determining the number of the at least two drift tubes; and determining the center position of each of the at least two drift tubes according to the number,
  • the step of determining the position where the cosmic ray particles are incident on the at least two drift tubes based on the drift distance includes:
  • the position where the cosmic ray particles are incident on the at least two drift tubes is determined.
  • an inspection method including the following steps:
  • the inspection method further includes: using the at least one scintillator, measuring the average momentum of the cosmic ray particles.
  • the step of calculating the scattering characteristic value of the cosmic ray particles under the action of the inspected object based on the incident track and the exit track includes:
  • the scattering characteristic value of the cosmic ray particles under the action of the inspected object is calculated.
  • the step of calculating the scattering characteristic value of the cosmic ray particles under the action of the inspected object based on the root mean square and the average momentum includes: calculating the scattering characteristic value by the following formula:
  • ⁇ ⁇ is the root mean square of the scattering angle
  • p is the average momentum of the incident particles
  • L is the thickness of the material through which the object to be inspected is passed by cosmic ray particles.
  • an apparatus for reconstructing the track of cosmic ray particles includes:
  • At least one scintillator for measuring the time zero point at which the cosmic ray particles are incident on the device
  • a plurality of drift tubes the plurality of drift tubes being configured to: under the action of the cosmic ray particles, the charged particles in at least 2 drift tubes of the plurality of drift tubes drift;
  • a computing device the computing device includes a memory and a processor, and the memory stores instructions, and when the instructions are executed by the processor, the following steps are implemented:
  • the track of the cosmic ray particles is fitted.
  • the multiple drift tubes include:
  • a plurality of first drift tubes located on at least two first drift tube layers and arranged along the first direction;
  • a plurality of second drift tubes located on at least 2 second drift tube layers and arranged in a second direction different from the first direction.
  • the distance between the center positions of two adjacent first drift tubes in the same first drift tube layer is greater than the diameter of the first drift tube.
  • the plurality of drift tubes are further configured to: in response to the drift of the charged particles in the at least 2 drift tubes, output at least 2 drift response signals; and
  • calculating the drift time of the charged particles in the at least two drift tubes according to the time zero includes:
  • the at least one scintillator is configured to:
  • the at least one scintillator is also used to measure the position where the cosmic ray particles are incident on the scintillator, and
  • fitting the track of the cosmic ray particles includes:
  • the track of the cosmic ray particles is fitted.
  • determining the position where the cosmic ray particles are incident on the at least two drift tubes based on the calculated drift time includes:
  • the position where the cosmic ray particles are incident on the at least two drift tubes is determined.
  • the following steps are further implemented: determining the number of the at least two drift tubes; and determining the center of each of the at least two drift tubes according to the number Location, and
  • determining the position where the cosmic ray particles are incident on the at least two drift tubes based on the drift distance includes:
  • the position where the cosmic ray particles are incident on the at least two drift tubes is determined.
  • an inspection device including:
  • the first cosmic ray particle detector is provided on the first side of the object to be inspected, and is used to reconstruct the incident track of the cosmic ray particles incident on the object to be inspected;
  • the second cosmic ray particle detector is provided on the second side of the object to be inspected opposite to the first side, and is used to reconstruct the exit track of the cosmic ray particles emitted from the object to be inspected,
  • At least one of the first cosmic ray particle detector and the second cosmic ray particle detector is the device according to any one of the above.
  • the inspection device further includes: a control device including a memory and a processor, and the memory stores instructions, and when the instructions are executed by the processor, the following steps are implemented:
  • any one of the inspection methods described above is also implemented.
  • FIG. 1 shows a schematic structural diagram of an inspection device according to an embodiment of the present disclosure
  • FIG. 2 shows a structural block diagram of the controller shown in FIG. 1;
  • FIG. 3 shows a perspective schematic view of a cosmic ray particle detector according to an embodiment of the present disclosure
  • FIG. 4 shows a schematic plan view of a cosmic ray particle detector in the XZ plane according to an embodiment of the present disclosure
  • FIG. 5 shows a schematic structural view of a scintillator of a cosmic ray particle detector according to an embodiment of the present disclosure
  • FIG. 6 shows a schematic structural diagram of a drift tube of a cosmic ray particle detector according to an embodiment of the present disclosure
  • FIG. 7 schematically illustrates a schematic diagram of cosmic ray particles passing through a group of detectors according to an embodiment of the present disclosure
  • 8A shows a schematic diagram of a plurality of drift tubes arranged closely
  • 8B shows a schematic diagram of a sparse arrangement of multiple drift tubes
  • FIG. 9A shows a schematic layout diagram of a cosmic ray particle detector in an inspection device according to an embodiment of the present disclosure
  • 9B is a schematic diagram describing the arrangement of a cosmic ray particle detector according to another embodiment of the present disclosure.
  • 9C is a schematic diagram illustrating the arrangement of a cosmic ray particle detector according to another embodiment of the present disclosure.
  • 9D is a schematic diagram illustrating the arrangement of a cosmic ray particle detector according to another embodiment of the present disclosure.
  • FIG. 10 is a schematic flowchart of a method for reconstructing a track of cosmic ray particles according to an embodiment of the present disclosure
  • FIG. 11 is a schematic flowchart of an inspection method according to an embodiment of the present disclosure.
  • FIG. 12 is a structural block diagram of an apparatus for reconstructing the tracks of cosmic ray particles according to an embodiment of the present disclosure.
  • the present disclosure it is proposed to use secondary particles generated by cosmic rays to inspect the object to be inspected.
  • the main particles when cosmic rays pass through the atmosphere to reach sea level are muzi ( ⁇ ) and electrons (e), the number ratio is about 10: 1.
  • the average energy of Muzi is about 3 / 4GeV, the mass is about 206 times of the negative electron, and the flux is about 10000 / (minute * m 2 ).
  • cosmic ray particles may refer to secondary particles produced by cosmic rays, such as muses ( ⁇ ) and electrons (e).
  • cosmic ray particles such as Muzi will undergo multiple Coulomb scattering when passing through matter, deviating from its original orbit, and the scattering angle has a corresponding relationship with the atomic number of matter, so it can be measured by measuring cosmic rays
  • the scattering angle distribution of particles after passing through the material is used for material identification.
  • the cosmic ray particle scattering effect of electrons is obvious, and medium / low Z substances passing through a certain thickness in the detection area are prone to large-angle deflection or absorption, and the distribution of low Z substances such as drugs / explosives can be analyzed.
  • the correspondence relationship or classification curve between the scattering angle and / or absorption characteristics and the various atomic number substances is established in advance, and then the scattering angle and / or absorption characteristics of the inspected object obtained by the actual inspection process are obtained correspondingly Atomic number value to determine the material properties of the inspected object.
  • FIG. 1 shows a schematic structural diagram of an inspection device according to an embodiment of the present disclosure.
  • the inspection device 100 includes a cosmic ray particle detector 160, a controller 140, and a monitoring device 150, and performs a security check on an inspected object 120, such as a container truck, for example, to determine whether nuclear material is contained therein and / or Or drugs such as drugs.
  • the cosmic ray particle detector 160 includes an incident cosmic ray particle detector 110 for detecting characteristic information of cosmic ray particles incident on the object 120 to be inspected, and is used to detect the object 120 after being inspected and emitted from the object 120
  • the characteristic information of the cosmic ray particles exits the cosmic ray particle detector 130.
  • the characteristic information may include information such as the position of the cosmic rays and the scattering angle.
  • the expression “detector” in this document may include a ray (particle) detector and a data collection device. For convenience of description, it is collectively referred to as a “detector”.
  • the radiation (particle) detector and the data collection can be integrated together to form a single device. Alternatively, the radiation detector and the data collection device may also be formed separately.
  • FIG. 2 shows a schematic structural diagram of the controller shown in FIG. 1.
  • the signals detected by the cosmic ray particle detectors 110 and 130 are collected by a data collector, and the data is stored in the memory 141 through the interface unit 147 and the bus 148.
  • the read-only memory (ROM) 142 stores configuration information and programs of the computer data processor.
  • a random access memory (RAM) 143 is used to temporarily store various data during the operation of the processor 145.
  • the memory 141 also stores computer programs for data processing, such as substance identification programs and image processing programs.
  • the internal bus 148 connects the aforementioned memory 141, read-only memory 142, random access memory 143, input device 144, processor 145, display device 146, and interface unit 147.
  • the instruction code of the computer program instructs the processor 145 to execute a predetermined data processing algorithm, and after obtaining the data processing result, displays it on a display such as an LCD display
  • the display result is processed on the display device 146 of the class or directly in the form of hard copy such as printing.
  • a cosmic ray particle detector 160 may include a first group of cosmic ray particle detectors 110 located on the upper side of the object 120 and a second group of cosmic rays on the lower side of the object 120 Particle detector 130.
  • the first group of cosmic ray particle detectors 110 are used to detect the characteristic information of cosmic rays incident on the object to be inspected 120, so they may also be called incident cosmic ray detectors or incident cosmic ray particle detectors.
  • the second group of cosmic ray particle detectors 130 are used to detect the characteristic information of cosmic rays emitted from the object 120 after passing the object 120, so they may also be called outgoing cosmic ray detectors or outgoing cosmic ray particle detectors.
  • FIG. 4 is a schematic plan view of a cosmic ray particle detector according to an embodiment of the present disclosure.
  • FIG. 4 is a plan view of FIG. 3 in the XZ plane.
  • the first group of cosmic ray particle detectors 110 may include a scintillator 31, a first drift tube group 32 and a second drift tube group 33.
  • the scintillator 31, the first drift tube group 32 and the second drift tube group 33 are arranged in order to approach the object 120 to be inspected in order.
  • the scintillator 31, the first drift tube group 32, and the second drift tube group 33 are all arranged on the upper side of the object under inspection 120, and are used to detect characteristic information of cosmic rays to be incident on the object under inspection 120, for example, the incident
  • the position and angle of the cosmic ray particle track 30 ie, the direction in the XYZ three-dimensional space.
  • the second group of cosmic ray particle detectors 130 may include a third drift tube group 34, a fourth drift tube group 35, and a scintillator 36.
  • the third drift tube group 34, the fourth drift tube group 35, and the scintillator 36 are arranged so as to be away from the object 120 to be inspected in order.
  • the third drift tube group 34, the fourth drift tube group 35, and the scintillator 36 are all arranged on the lower side of the object under inspection 120, and are used to detect characteristic information of cosmic rays emitted from the object under inspection 120 after passing through the object under inspection 120 For example, the position and angle of the outgoing cosmic ray particle track 30 '(ie, the direction in the XYZ three-dimensional space).
  • the scintillator 31 may adopt a structure such as a scintillation fiber, a scintillator flat plate, and a scintillator bar coupled wave-shifting fiber.
  • cosmic ray particles such as Muzi enter the scintillator 31
  • the incident cosmic ray particles lose energy, ionizing and exciting atoms in the scintillator 31, and emit fluorescence when deexcitation.
  • the process before the number of emitted photons reaches the maximum is the increasing process of the scintillator 31 luminescence, and the time is generally on the order of nanoseconds (ns).
  • the scintillator has the advantages of high luminous efficiency, short luminescence decay time, and good optical properties, and is suitable for time measurement. As shown in FIG.
  • a photon counter 51 such as a photomultiplier tube (PMT) or a silicon photomultiplier (SiPM) is installed at both ends of the scintillator 31, and fluorescent photons generated when cosmic ray particles (such as mummies) pass through the scintillator 31
  • Photoelectrons ie, charged particles
  • the electrons are continuously accelerated by the electric field between the two electrodes. After multiplication, more electrons are generated.
  • the current formed by the convergence of the electrons is output as a voltage signal after passing through the load resistance.
  • the scintillator 36 may have the same structure and configuration as the scintillator 31, which will not be repeated here.
  • the first drift tube group 32 may include a first drift tube layer 321, a second drift tube layer 322, a third drift tube layer 323 and a fourth drift tube layer 324.
  • the first drift tube layer 321 may include a plurality of drift tubes 600 arranged along a first direction (in the illustrated embodiment, the first direction is the X direction), and the second drift tube layer 322 may also include Multiple drift tubes 600.
  • the third drift tube layer 323 may include a plurality of drift tubes 600 arranged along the second direction (in the illustrated embodiment, the second direction is the Y direction), and the fourth drift tube layer 324 also includes the ones arranged along the second direction Multiple drift tubes 600.
  • FIG. 6 shows a schematic diagram of a drift tube according to an embodiment of the present disclosure, in which cosmic ray particles such as mummies pass through the drift tube.
  • the drift tube 600 may include a metal tube 601 serving as a cathode and a metal wire 602 serving as an anode.
  • the metal wire 602 is located at the center of the metal tube 601 and extends in the axial direction of the metal tube 601.
  • the metal tube 601 is filled with a gas, for example, a mixed gas of argon and carbon dioxide at 3 atmospheres.
  • a high voltage of about +2 to 3 kV can be applied to the metal wire 602, and the metal tube 601 is grounded, so that a high-voltage electrostatic field is formed between the metal wire 601 and the metal tube 602.
  • cosmic ray particles such as Muzi pass through the drift tube 600, the cosmic ray particles interact with gas atoms, causing many charged particles, such as electrons 610, to drift toward the positively charged anode wire 602.
  • the metal tube 601 may be an aluminum tube with an inner diameter of 30 mm; the metal wire 602 may be a gold-plated tungsten wire with a diameter of about 50 ⁇ m.
  • the drift speed of the electron 610 in the drift tube is the design value, for example, 30 ⁇ m / ns.
  • the drift speed is multiplied by the drift time to obtain the drift distance. Since the drift speed is a design value, that is, it is a certain value, the drift time-drift distance relationship of the drift tube can be established in advance.
  • the drift distance of the electron 610 is determined by the position of the cosmic ray particles passing through the drift tube 600, and the position of the cosmic ray particles passing through the drift tube 600 can be determined by the calculated drift distance.
  • the positions of the cosmic ray particles passing through the multiple drift tubes 600 are determined, the track of the cosmic ray particles can be reconstructed.
  • the drift time ⁇ T 1 T 1 -T 0 . According to the pre-established drift time-drift distance relationship of the drift tube, the drift distance can be calculated.
  • the particles that can be simultaneously received by two, three, or several layers of cosmic ray particle detectors at a certain distance are the same cosmic ray particle.
  • the position, reception time and energy of the received particles are recorded by an electronic system such as a data acquisition device, and the walking path and action position of the particles are calculated through the analysis of the reception time difference.
  • two particles received by different detectors within a short time (such as 1 nanosecond) are considered to belong to the same source.
  • a group of detectors can determine the incident path of the particles, and a group of detectors on the other side of the object can be used to determine the exit path of the particles, thereby determining the object to the universe based on the incident path and the exit path The location of the rays and the scattering angle.
  • FIG. 7 schematically shows that cosmic ray particles pass through a detector according to an embodiment of the present disclosure.
  • cosmic ray particles P are shown to sequentially pass through the scintillator 31 of the detector, the first drift tube layer 321, and the second drift tube layer 322.
  • the cosmic ray particles P pass through the detector at a speed close to the speed of light, that is, it can be considered that the cosmic ray particles P begin to pass through the scintillator 31, the first drift tube layer 321, and the second drift tube layer The moment of 322 is very close.
  • the drift time is generally on the order of microseconds
  • the time from the cosmic ray particles entering the detector to the scintillator 31 generating an electronic response is about several nanoseconds, which is sufficiently short for the drift time on the order of microseconds, Therefore, the time at which the scintillator 31 generates the electronic response can be regarded as the true time zero point, that is, the time at which the scintillator 31 generates the electronic response can be regarded as the time zero point T 0 .
  • the coordinate value on the X axis of the response position on the scintillator 31 is recorded, for example, X 0 .
  • one drift tube 600 in the first drift tube layer 321 and one drift tube 600 in the second drift tube layer 322 will generate a response.
  • the number of the responding drift tube 600 in the first drift tube layer 321 can be recorded as ID 1X and the response time is T 1 ; and the number of the responding drift tube 600 in the second drift tube layer 322 can be recorded as ID 2X ,
  • the response time is T 2 .
  • the drift time can be calculated.
  • the drift time ⁇ T 1 T 1 -T 0
  • the coordinates of the center position of the ID 1X and ID 2X drift tubes 600 (such as the center axis of the drift tube) on the X axis are obtained The values X ID1 and X ID2 .
  • a linear fitting step may be performed to fit the tracks of the cosmic ray particles P.
  • the center of the drift tube 600 with ID 1X and ID 2X can be taken as the center of the circle, and the drift distances r 1 and r 2 can be used as radii to draw the drift circle (shown by the broken circle in the figure).
  • the combination of the drift tube and the scintillator helps to obtain the real time zero point needed to reconstruct the trail of cosmic ray particles, so as to select the track that best matches the actual situation, so that it can be more accurately reconstructed Cosmic ray particle track.
  • the tangent direction of the cosmic ray particle track and the drift circle may not be directly determined, as shown in FIG. 7 by the broken line track as the interference track.
  • the position of the cosmic ray particles on the scintillator (such as the above-mentioned position X 0 ) does not require the scintillator 31 to have a high spatial resolution and can be easily The real track is screened out, and the accuracy is high, which greatly simplifies the data processing process.
  • the reconstruction method of the cosmic ray particles in the XZ plane is described in detail. It should be understood that the scintillator 31 and the third drift tube layer 323 of the detector can be sequentially passed according to the cosmic ray particles P 4. An example of the fourth drift tube layer 324 to reconstruct the track of cosmic ray particles in the YZ plane.
  • the reconstruction method may be the same as the reconstruction method in the XZ plane described above, which will not be repeated here.
  • the tracks of the cosmic ray particles in the XZ and YZ planes can be reconstructed, so that the cosmic ray particles P can be reconstructed in the space coordinate system
  • the incident track incident on the object 120 to be inspected is inspected.
  • the tracks of the cosmic ray particles in the XZ and YZ planes can be reconstructed, so that the cosmic ray particles P can be reconstructed in the space coordinate system The exit path after exiting the object 120 under inspection.
  • each group of detectors includes a combination of a scintillator and a drift tube.
  • the scintillator By adding the scintillator, the cosmic ray particle incidence required by the drift tube positioning can be provided The zero point of time helps to pick the track that best meets the real situation.
  • the cosmic ray particle P by reconstructing the incident track of the cosmic ray particle P incident on the object 120 to be inspected and the exit track after passing through the object 120 to be inspected, it can be determined that the cosmic ray particle P passes through the object to be inspected Scattering angle after 120, and there is a corresponding relationship between the scattering angle distribution and the atomic number of the substance. Based on the previously established correspondence relationship or classification curve between the scattering angle distribution and the various atomic number substances, the Material properties.
  • the cosmic ray particle detectors 110 and 130 may further include a computing device 180. That is, the cosmic ray particle detector according to an embodiment of the present disclosure may include: at least one scintillator 31, 36 for measuring the time zero point at which the cosmic ray particles are incident on the device; a plurality of drift tubes 600, the plurality of drifts The tube is configured to: under the action of the cosmic ray particles, the charged particles in at least two of the plurality of drift tubes drift; and the calculation device 180.
  • the computing device 180 may include a memory 181 and a processor 182, where instructions are stored on the memory 181, and when the instructions are executed by the processor 182, the following steps are implemented: according to the time zero, calculate the The drift time of the charged particles in at least 2 drift tubes; based on the calculated drift time, determining the position where the cosmic ray particles are incident on the at least 2 drift tubes; and based on the determined cosmic ray particles being incident on the at least 2 The position of the drift tube is fitted to the track of cosmic ray particles.
  • the cosmic ray particle detector can be regarded as a device for reconstructing the tracks of cosmic ray particles.
  • the apparatus for reconstructing the tracks of cosmic ray particles may include a computing device 180, and the computing device 180 may include a memory 181 and a processor 182.
  • the memory 181 stores instructions, and when the instructions are processed
  • the implement 182 implements a method for reconstructing the tracks of cosmic ray particles according to an embodiment of the present disclosure.
  • the inspection apparatus may include an apparatus and a control device (for example, the controller 140 shown in FIG. 1) for reconstructing the tracks of cosmic ray particles.
  • the control device may include a memory and a processor, and the memory stores instructions, and when the instructions are executed by the processor, an inspection method according to an embodiment of the present disclosure is implemented.
  • the memory and processor of the control device included in the inspection device may be integrated with the memory and processor of the computing device included in the device for reconstructing the tracks of cosmic ray particles, respectively.
  • the memory and processor of the control device may be set independently of the memory and processor of the computing device, respectively. That is to say, the embodiments of the present disclosure do not specifically limit the manner of setting the memory and the processor.
  • a group of detectors 110, 130 are arranged on the top and bottom of the object 120 to be inspected, and each group of detectors 110, 130 contains three parallel superlayers, that is, the superlayer where the scintillator is located and 2 drifts The super layer where the tube group is located.
  • Each drift tube group includes 4 drift tube layers to obtain the X-axis and Y-axis positions.
  • drift tube layers 321, 322 two layers of drift tubes (eg, drift tube layers 321, 322) are used to measure the X-axis position, and another two layers of drift tubes (eg, drift tube layers 323, 324) are used Measure the Y-axis position, so as to avoid the loss of detection efficiency caused by the drift tube wall or the gap between the tubes.
  • one drift tube group may include less than 4 layers of drift tubes, for example, one drift tube group may include 2 layers of drift tubes, one layer of drift tubes is used to measure the X-axis position, and the other layer of drift tubes is used to Measuring the Y-axis position; one drift tube group can include more than 4 layers of drift tubes, for example, one drift tube group can include 6 layers of drift tubes, where three layers of drift tubes are used to measure the X-axis position and the other three layers of drift tubes are used to measure Y-axis position.
  • the drift tubes in the drift tube layer may be arranged sparsely, thereby effectively reducing manufacturing costs.
  • FIG. 8A and FIG. 8B schematic diagrams of the close arrangement and the sparse arrangement of the drift tubes are shown, respectively.
  • the radius of each drift tube is R
  • the total length of the drift tube layer is L.
  • the horizontal angle of the connection between the two adjacent drift tubes is ⁇ (0 ° ⁇ ⁇ 60 °)
  • the arrangement of the drift tube can cover all the cosmic ray particles at the incident angle, which can save the number of drift tubes without affecting the overall detection efficiency.
  • the detector groups can also be set on both sides of the object to be inspected, even front and back, using multi-faceted detector measurement methods, such as four groups (upper and lower sides, two sides), six groups (upper and lower sides, two sides) , Front and back), etc.
  • the detector group includes an upper detector 910, a lower detector 911, a left detector 912, a right detector 913, a front detector 915, and a rear detector 914, distributed around the object 120 to be inspected.
  • a detector arrangement that is horizontal or inclined at the top and bottom, and the detectors on both sides maintain a certain angle with the ground (exposed U-shaped arrangement).
  • a continuous large-area detector can be used in the walking direction to obtain sufficient particle information. It is noted that the time when the object to be inspected 120 enters the entrance of the tunnel is t1, and the time when it leaves the exit is t2, the total length of the vehicle is 1, the vehicle speed is maintained at about v meters / second, and the total length of the tunnel is about (t2-t1) ⁇ v.
  • a small area detector or a segmented detector can also be used to perform parking inspection on the designated area of the inspected object, as shown in FIGS. 9B, 9C, and 9D.
  • the object 120 to be inspected is stopped to the measurement area and inspected. For example, the suspicious object 121 is located exactly between the upper detector 920 of a small area and the lower detector 921 of a small area, thereby facilitating inspection.
  • the small-area detector 921 or the segmented bottom detectors 922, 923, and 924 can be buried underground, and the suspicious area 121 of the inspected object is located right between the top detector 920 and the bottom detector 921 . It is also possible to make the bottom surface detectors 922, 923 and 924 protrude above the ground, just separated by the wheels. Although the use of such small-area or segmented detectors may collect less data than continuous large-area detectors, it can reduce the difficulty of detector design, system construction and maintenance, simplify the system structure, and reduce the cost of hardware and software.
  • a continuous large-area position sensitive detector is used to detect the trajectory of a moving vehicle. Since the vehicle is moving in the inspection channel, it is necessary to use the monitoring device 150 to record the driving trajectory of the vehicle in order to conform to the position of the cosmic ray particles detected by the detector.
  • Conventional methods include video positioning, optical path positioning, and pressure sensing. Since the vehicle travels slowly and the route is approximately straight, the requirements for the monitoring device 150 need not be excessive. If multiple cameras are used for video tracking, only the top-view camera is required to meet the positioning requirements. In other embodiments, when using optical path positioning, only one row of optical paths needs to be placed on the side of the vehicle.
  • a large amount of data generated during the scanning process can be transmitted to a back-end data processing workstation through wireless transmission or optical cables, network cables, and other lines.
  • the wired transmission mode is recommended, which can not only ensure the speed of data transmission, reduce the loss of the signal in the transmission process, improve the anti-interference ability of the signal transmission, but also greatly reduce the technical difficulty of data collection And cost.
  • the embodiments of the present disclosure may provide a method for reconstructing the tracks of cosmic ray particles. As shown in FIG. 10, the method may include the following steps:
  • the cosmic ray particle detector includes at least one scintillator and a plurality of drift tubes, so that the charged particles in at least 2 drift tubes of the plurality of drift tubes drift;
  • the above method may further include: outputting at least 2 drift response signals in response to the drift of the charged particles in at least 2 drift tubes 600; and recording at least 2 response moments that generate at least 2 drift response signals.
  • the above step S104 may specifically include: separately calculating the difference between the at least two response moments and the time zero point, and using the difference as the drift time of the charged particles in the at least two drift tubes.
  • the above step S102 may specifically include: in response to the cosmic ray particles P incident on at least one scintillator 31, outputting at least one scintillator response signal; and recording the generation of the at least one scintillator response signal The response time of the scintillator determines the response time of the scintillator as the time zero point.
  • the above method may further include: using at least one scintillator 31 to measure the position where the cosmic ray particles are incident on the scintillator 31, for example, the position X 0 in FIG. 7.
  • the above step S105 may specifically include: according to the determined position of the cosmic ray particles incident on at least two drift tubes (for example, the position shown in FIG. 7) and the measured cosmic ray particles incident on the scintillator 31 Position (for example, position X 0 in FIG. 7), the track of the cosmic ray particle P is fitted.
  • an embodiment of the present disclosure also provides an inspection method. As shown in FIG. 11, the inspection method may include the following steps:
  • the cosmic ray particle detector includes at least one scintillator and a plurality of drift tubes ;
  • S114 Calculate the scattering characteristic value of cosmic ray particles under the action of the object under inspection based on the incident track and the exit track;
  • the incident track and the exit track can be reconstructed using the reconstruction method described above.
  • the scintillators 31 and 36 may be suitable for time measurement on the order of nanoseconds (ns). In this way, when the cosmic ray particles pass through the scintillator at the speed of light, the time it takes to pass through the detection area is on the order of nanoseconds.
  • the scintillators 31 and 36 are used to directly measure the propagation time of cosmic ray particles, thereby directly calculating the momentum of the cosmic ray particles.
  • the output pulse amplitude of the scintillators 31, 36 is proportional to the momentum of the incident cosmic ray particles, and the momentum of the cosmic ray particles can also be calculated by measuring the output pulse amplitude of the scintillator 31, 36 .
  • the momentum of the cosmic ray particles can also be divided into multiple levels, for example, the momentum of the cosmic ray particles can be graded and recorded as ( ⁇ E, 2 ⁇ E, ..., N ⁇ E).
  • the inspection method according to the embodiment of the present disclosure may further include: using the at least one scintillator, measuring the average momentum of the cosmic ray particles.
  • step S114 may specifically include:
  • the scattering characteristic value of the cosmic ray particles under the action of the inspected object is calculated.
  • the following scattering density calculation formula can be used to calculate the scattering characteristic value:
  • ⁇ ⁇ is the root mean square of the scattering angle
  • p is the average momentum of the incident particles
  • L is the thickness of the material through which the object 120 to be inspected is passed by cosmic ray particles.
  • the first group of detectors can determine the particle's incident track
  • the other group of detectors on the other side of the object can be used to determine the particle's exit track, thereby determining the pair of objects to be checked based on the incident track and the exit track
  • the location and scattering angle of cosmic rays can be calculated based on the detected value of the scintillator.
  • blocking capacity calculation formula can also be used to calculate the blocking capacity value:
  • N scatter / (a scatter ⁇ t scatter ) represents the number of particles that scatter with the substance detected on the image area or volume of a scatter within t scatter time N scatter
  • N stop / (a stop ⁇ t stop ) Represents the number N stop of particles that block with matter in the imaging area or volume of a stop during t stop time
  • p is the average momentum of the incident particles
  • L is the thickness of the material through which the object 120 to be inspected is penetrated by cosmic ray particles.
  • a particle is detected by the incident detector and the exit detector at the same time in a short time, it is considered to be a scattered particle; if it enters the measurement area but is only detected by the incident detector and the exit detector does not receive information, it is considered to be Block particles.
  • the inspection method may include the step of: using the calculated blocking ability value to distinguish the material properties of the low Z zone. For example, through the correspondence table between the blocking ability value and the atomic number of some substances measured in advance, the atomic number of the region of interest is determined by looking up the table to determine the material properties.
  • signal-bearing media include, but are not limited to: recordable media such as floppy disks, hard drives, compact disks (CDs), digital versatile disks (DVDs), digital magnetic tapes, computer memories, etc .; and transmission media such as digital and / Or analog communication media (eg, fiber optic cables, waveguides, wired communication links, wireless communication links, etc.).

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Abstract

一种用于重建宇宙射线粒子的径迹的方法,包括：利用宇宙射线粒子探测器(160)探测宇宙射线粒子，宇宙射线粒子探测器(160)包括至少一个闪烁体(31)和多个漂移管(32,33,34,35)，在宇宙射线粒子的作用下，多个漂移管中的至少2个漂移管中的带电粒子产生漂移；利用至少一个闪烁体(31)，记录宇宙射线粒子入射至所述宇宙射线粒子探测器(160)的时间零点；根据时间零点，计算至少2个漂移管中带电粒子的漂移时间；基于计算出的漂移时间，确定宇宙射线粒子入射至所述至少2个漂移管的位置；和根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置，拟合出宇宙射线粒子的径迹。还提供了一种相关的设备、检查方法以及检查设备。

Description

重建粒子径迹的方法和设备、以及检查方法和检查设备
相关申请的交叉引用
本申请要求于2018年11月1日递交中国专利局的、申请号为201811294703.4的中国专利申请的权益，该申请的全部公开内容以引用方式并入本文。
技术领域
本公开涉及对辐射检测技术，具体涉及一种用于重建宇宙射线粒子的径迹的方法和设备、以及对诸如集装箱卡车之类的被检查物体进行检查的设备和方法。
背景技术
宇宙射线成像技术利用自然界天然存在的宇宙射线为辐射源，穿透力强，无外加辐射，已被证实可用于检查核燃料、核废料、屏蔽体等高原子序数材料，以及毒品、爆炸物等中-低原子序数材料。
宇宙射线检查与物质识别的关键在于宇宙射线粒子的径迹重建方法。目前的径迹重建方法，主要通过线性拟合和迭代算法来获取最优解，迭代初值为经验选取。这种径迹重建方法过于依赖经验，当初值偏离较多或漂移管性能差异大时，会产生较大误差，定位准确度和重建效果不佳。
发明内容
考虑到现有技术中的一个或多个问题，提出了一种用于重建宇宙射线粒子的径迹的方法和设备、以及对诸如集装箱卡车之类的被检查物体进行检查的设备和方法。
在一个方面，提供一种用于重建宇宙射线粒子的径迹的方法，包括以下步骤：
利用宇宙射线粒子探测器探测宇宙射线粒子，所述宇宙射线粒子探测器包括至少一个闪烁体和多个漂移管，在所述宇宙射线粒子的作用下，所述多个漂移管中的至少2个漂移管中的带电粒子产生漂移；
利用所述至少一个闪烁体，记录宇宙射线粒子入射至所述宇宙射线粒子探测器的时间零点；
根据所述时间零点，计算所述至少2个漂移管中带电粒子的漂移时间；
基于计算出的漂移时间，确定宇宙射线粒子入射至所述至少2个漂移管的位置；和
根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置，拟合出宇宙射线粒子的径迹。
可选地，所述方法还可以包括：
响应于所述至少2个漂移管中的带电粒子的漂移，输出至少2个漂移响应信号；和
记录产生所述至少2个漂移响应信号的至少2个响应时刻，
其中，根据所述时间零点，计算所述至少2个漂移管中带电粒子的漂移时间，包括：
分别计算所述至少2个响应时刻与所述时间零点的差值，将所述差值分别作为所述至少2个漂移管中带电粒子的漂移时间。
可选地，所述利用所述至少一个闪烁体，记录宇宙射线粒子入射至所述宇宙射线粒子探测器的时间零点的步骤包括：
响应于所述宇宙射线粒子入射至所述至少一个闪烁体，输出至少一个闪烁体响应信号；和
记录产生所述至少一个闪烁体响应信号的闪烁体响应时刻，将该闪烁体响应时刻确定为所述时间零点。
可选地，所述方法还包括：利用所述至少一个闪烁体，测量宇宙射线粒子入射至所述闪烁体的位置，
其中，所述根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置，拟合出宇宙射线粒子的径迹的步骤包括：
根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置以及测量出的宇宙射线粒子入射至所述闪烁体的位置，拟合出宇宙射线粒子的径迹。
可选地，所述基于计算出的漂移时间，确定宇宙射线粒子入射至所述至少2个漂移管的位置的步骤包括：
基于预先建立的漂移时间与漂移距离之间的对应关系，确定所述至少2个漂移管中的带电粒子的漂移距离；和
基于所述漂移距离，确定宇宙射线粒子入射至所述至少2个漂移管的位置。
可选地，所述方法还包括：确定所述至少2个漂移管的编号；和根据所述编号，确定所述至少2个漂移管中每一个的中心位置，
其中，所述基于所述漂移距离，确定宇宙射线粒子入射至所述至少2个漂移管的位置的步骤包括：
基于所述漂移距离和所述中心位置，确定宇宙射线粒子入射至所述至少2个漂移管的位置。
在另一方面，还提供一种检查方法，包括以下步骤：
利用宇宙射线粒子探测器探测入射至被检查物体的宇宙射线粒子和从被检查物体出射的宇宙射线粒子，所述宇宙射线粒子探测器包括至少一个闪烁体和多个漂移管；
利用上述任一项所述的方法，重建入射至被检查物体的宇宙射线粒子的入射径迹；
利用上述任一项所述的方法，重建从被检查物体出射的宇宙射线粒子的出射径迹；
基于所述入射径迹和所述出射径迹，计算宇宙射线粒子在被检查物体作用下的散射特性值；和
利用所述散射特性值，识别所述被检查物体的材料属性。
可选地，所述检查方法还包括：利用所述至少一个闪烁体，测量宇宙射线粒子的平均动量。
可选地，所述基于所述入射径迹和所述出射径迹，计算宇宙射线粒子在被检查物体作用下的散射特性值的步骤包括：
计算所述入射径迹与所述出射径迹之间的散射角度；
计算散射角度的均方根；和
基于所述均方根和所述平均动量，计算宇宙射线粒子在被检查物体作用下的散射特性值。
可选地，所述基于所述均方根和所述平均动量，计算宇宙射线粒子在被检查物体作用下的散射特性值的步骤包括：通过下式计算散射特性值：
Figure PCTCN2019103057-appb-000001
其中，σ θ为散射角度的均方根，p为入射粒子的平均动量，L为所述被检查物体被宇宙射线粒子穿过的材料的厚度。
在又一方面，提供一种用于重建宇宙射线粒子的径迹的设备，包括：
至少一个闪烁体，用于测量宇宙射线粒子入射至所述设备的时间零点；
多个漂移管，所述多个漂移管被配置为：在所述宇宙射线粒子作用下，所述多个漂移管中的至少2个漂移管中的带电粒子产生漂移；和
计算装置，所述计算装置包括存储器和处理器，所述存储器上存储有指令，当所述指令被所述处理器执行时实现以下步骤：
根据所述时间零点，计算所述至少2个漂移管中带电粒子的漂移时间；
基于计算出的漂移时间，确定宇宙射线粒子入射至所述至少2个漂移管的位置；和
根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置，拟合出宇宙射线粒子的径迹。
可选地，所述多个漂移管包括：
位于至少2个第一漂移管层且沿第一方向布置的多个第一漂移管；和
位于至少2个第二漂移管层且沿不同于第一方向的第二方向布置的多个第二漂移管。
可选地，位于同一个第一漂移管层中的2个相邻的第一漂移管的中心位置之间的距离大于第一漂移管的直径。
可选地，所述多个漂移管还被配置为：响应于所述至少2个漂移管中的带电粒子的漂移，输出至少2个漂移响应信号；和
记录产生所述至少2个漂移响应信号的至少2个响应时刻，以及
其中，根据所述时间零点，计算所述至少2个漂移管中带电粒子的漂移时间，包括：
分别计算所述至少2个响应时刻与所述时间零点的差值，将所述差值分别作为所述至少2个漂移管中带电粒子的漂移时间。
可选地，所述至少一个闪烁体被配置为：
响应于所述宇宙射线粒子入射至所述至少一个闪烁体，输出至少一个闪烁体响应信号；和
记录产生所述至少一个闪烁体响应信号的闪烁体响应时刻，将该闪烁体响应时刻确定为所述时间零点。
可选地，所述至少一个闪烁体还用于测量宇宙射线粒子入射至所述闪烁体的位置，以及
其中，根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置，拟合出宇 宙射线粒子的径迹包括：
根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置以及测量出的宇宙射线粒子入射至所述闪烁体的位置，拟合出宇宙射线粒子的径迹。
可选地，基于计算出的漂移时间，确定宇宙射线粒子入射至所述至少2个漂移管的位置，包括：
基于预先建立的漂移时间与漂移距离之间的对应关系，确定所述至少2个漂移管中的带电粒子的漂移距离；和
基于所述漂移距离，确定宇宙射线粒子入射至所述至少2个漂移管的位置。
可选地，当所述指令被所述处理器执行时还实现以下步骤：确定所述至少2个漂移管的编号；和根据所述编号，确定所述至少2个漂移管中每一个的中心位置，以及
其中，基于所述漂移距离，确定宇宙射线粒子入射至所述至少2个漂移管的位置，包括：
基于所述漂移距离和所述中心位置，确定宇宙射线粒子入射至所述至少2个漂移管的位置。
在另一方面，还提供一种检查设备，包括：
第一宇宙射线粒子探测器，设置在被检查物体的第一侧，用于重建入射至被检查物体的宇宙射线粒子的入射径迹；和
第二宇宙射线粒子探测器，设置在被检查物体的与所述第一侧相对的第二侧，用于重建从被检查物体出射的宇宙射线粒子的出射径迹，
其中，所述第一宇宙射线粒子探测器和所述第二宇宙射线粒子探测器中的至少一个为上述任一项所述的设备。
可选地，所述检查设备还包括：控制装置，所述控制装置包括存储器和处理器，所述存储器上存储有指令，当所述指令被所述处理器执行时实现以下步骤：
基于所述入射径迹和所述出射径迹，计算宇宙射线粒子在被检查物体作用下的散射特性值；和
利用所述散射特性值，识别所述被检查物体的材料属性。
可选地，当所述指令被所述处理器执行时，还实现上述任一项所述的检查方法。
附图说明
为了更好地理解本公开，将根据以下附图对本公开进行详细描述：
图1示出了根据本公开实施例的检查设备的结构示意图；
图2示出了如图1所示的控制器的结构框图；
图3示出了根据本公开实施例的宇宙射线粒子探测器的立体示意图；
图4示出了根据本公开实施例的宇宙射线粒子探测器在XZ平面内的平面示意图；
图5示出了根据本公开实施例的宇宙射线粒子探测器的闪烁体的结构示意图；
图6示出了根据本公开实施例的宇宙射线粒子探测器的漂移管的结构示意图；
图7示意性示出了根据本公开实施例的宇宙射线粒子穿过一组探测器的示意图；
图8A示出了多个漂移管紧密排列的示意图；
图8B示出了多个漂移管稀疏排列的示意图；
图9A示出了根据本公开实施例的检查设备中宇宙射线粒子探测器的布置示意图；
图9B是描述根据本公开另一实施例的宇宙射线粒子探测器的布置示意图；
图9C是描述根据本公开另一实施例的宇宙射线粒子探测器的布置示意图；
图9D是描述根据本公开另一实施例的宇宙射线粒子探测器的布置示意图；
图10是根据本公开实施例的用于重建宇宙射线粒子的径迹的方法的示意性流程图；
图11是根据本公开实施例的检查方法的示意性流程图；和
图12是根据本公开实施例的用于重建宇宙射线粒子的径迹的设备的结构框图。
具体实施方式
下面将详细描述本公开的具体实施例，应当注意，这里描述的实施例只用于举例说明，并不用于限制本公开。在以下描述中，为了提供对本公开的透彻理解，阐述了大量特定细节。然而，对于本领域普通技术人员显而易见的是：不必采用这些特定细节来实行本公开。在其他实例中，为了避免混淆本公开，未具体描述公知的结构、材料或方法。
在整个说明书中，对“一个实施例”、“实施例”、“一个示例”或“示例”的提及意味着：结合该实施例或示例描述的特定特征、结构或特性被包含在本公开至少一个实施例中。因此，在整个说明书的各个地方出现的短语“在一个实施例中”、“在实施例中”、“一个示例”或“示例”不一定都指同一实施例或示例。此外，可以以任何适当的组合和/或子组合将特定的特征、结构或特性组合在一个或多个实施例或示例中。 此外，本领域普通技术人员应当理解，这里使用的术语“和/或”包括一个或多个相关列出的项目的任何和所有组合。
在本公开的实施例中，提出使用宇宙射线产生的次级粒子对被检查物体进行检查。宇宙射线经过大气层到达海平面时的主要粒子为缪子(μ)和电子(e)，数量比例约为10∶1。缪子平均能量强，约为3/4GeV，质量约为负电子的206倍，通量约为10000/(minute*m 2)。经测量，能量为4GeV的缪子在铅等高Z物质中的最大穿透深度超过一米，而更高能量的缪子可穿透数十米的岩石和金属，故宇宙射线缪子可穿透集装箱车辆/货物可能存在的重核物质进行检测。在本文中，宇宙射线粒子可以指宇宙射线产生的次级粒子，例如缪子(μ)和电子(e)。
此外，根据本公开的实施例，例如缪子的宇宙射线粒子穿过物质时会发生多次库仑散射，偏离其原先的轨道，散射角度和物质的原子序数存在对应关系，故可通过测量宇宙射线粒子穿过物质后的散射角分布进行材料识别。另外，例如电子的宇宙射线粒子散射作用明显，在探测区域内穿过一定厚度的中/低Z物质容易发生大角度偏转或被吸收，可以分析毒品/爆炸物等低Z物质的分布情况。例如事先建立散射角度和/或吸收特性与各种原子序数的物质之间的对应关系或者分类曲线，然后在实际检查过程中通过采集得到的被检查物体的散射角和/或吸收特性得到相应的原子序数值，从而确定被检查物体中的材料属性。
图1示出了根据本公开实施例的检查设备的结构示意图。如图1所示，检查设备100包括宇宙射线粒子探测器160、控制器140和监控设备150，对诸如集装箱卡车之类的被检查物体120进行安全检查，例如判断其中是否包含了核材料和/或毒品等违禁品。例如，宇宙射线粒子探测器160包括用于探测入射至被检查物体120的宇宙射线粒子的特征信息的入射宇宙射线粒子探测器110、和用于探测经过被检查物体120后从被检查物体120射出的宇宙射线粒子的特征信息的出射宇宙射线粒子探测器130。例如，所述特征信息可以包括宇宙射线的位置、散射角度等信息。
需要说明的是，本文中的表述“探测器”可以包括射线(粒子)探测器和数据采集装置，为了描述方便，将其统称为“探测器”。并且，所述射线(粒子)探测器和所述数据采集可以集成在一起形成单一设备。或者，所述射线探测器和所述数据采集装置也可以分开形成。
图2示出了如图1所示的控制器的结构示意图。如图2所示，宇宙射线粒子探测器110、130探测的信号通过数据采集器采集，数据通过接口单元147和总线148存储 在存储器141中。只读存储器(ROM)142中存储有计算机数据处理器的配置信息以及程序。随机存取存储器(RAM)143用于在处理器145工作过程中暂存各种数据。另外，存储器141中还存储有用于进行数据处理的计算机程序，例如物质识别程序和图像处理程序等等。内部总线148连接上述的存储器141、只读存储器142、随机存取存储器143、输入装置144、处理器145、显示装置146和接口单元147。
在用户通过诸如键盘和鼠标之类的输入装置144输入的操作命令后，计算机程序的指令代码命令处理器145执行预定的数据处理算法，在得到数据处理结果之后，将其显示在诸如LCD显示器之类的显示装置146上，或者直接以诸如打印之类硬拷贝的形式输出处理结果。
图3是根据本公开实施例的宇宙射线粒子探测器的立体示意图。请参照图3，根据本公开实施例的宇宙射线粒子探测器160可以包括位于被检查物体120上侧的第一组宇宙射线粒子探测器110和位于被检查物体120下侧的第二组宇宙射线粒子探测器130。第一组宇宙射线粒子探测器110用于探测入射至被检查物体120的宇宙射线的特征信息，所以也可以称为入射宇宙射线探测器或入射宇宙射线粒子探测器。第二组宇宙射线粒子探测器130用于探测经过被检查物体120后从被检查物体120射出的宇宙射线的特征信息，所以也可以称为出射宇宙射线探测器或出射宇宙射线粒子探测器。
图4是根据本公开实施例的宇宙射线粒子探测器的平面示意图。例如，图4是图3在XZ平面内的平面图。结合图3和图4所示，第一组宇宙射线粒子探测器110可以包括闪烁体31、第一漂移管组32和第二漂移管组33。闪烁体31、第一漂移管组32和第二漂移管组33以依次靠近被检查物体120的方式布置。闪烁体31、第一漂移管组32和第二漂移管组33均布置在被检查物体120的上侧，用于探测将入射至被检查物体120中的宇宙射线的特征信息，例如，入射的宇宙射线粒子径迹30的位置和角度(即，XYZ三维空间中的方向)。
第二组宇宙射线粒子探测器130可以包括第三漂移管组34、第四漂移管组35和闪烁体36。第三漂移管组34、第四漂移管组35和闪烁体36以依次远离被检查物体120的方式布置。第三漂移管组34、第四漂移管组35和闪烁体36均布置在被检查物体120的下侧，用于探测穿过被检查物体120后从被检查物体120出射的宇宙射线的特征信息，例如，出射的宇宙射线粒子径迹30’的位置和角度(即，XYZ三维空间中的方向)。
例如，闪烁体31可以采用诸如闪烁纤维、闪烁体平板、闪烁体条耦合移波光纤等 结构。当例如缪子的宇宙射线粒子入射到闪烁体31内后，入射的宇宙射线粒子损失能量，使闪烁体31内的原子电离、激发，在退激发时就会发射出荧光。在发射光子数达到最大值之前的过程是闪烁体31发光的增加过程，时间一般为纳秒(ns)量级。闪烁体具有高发光效率、发光衰减时间短、良好的光学性质等优点，适合用于时间测量。如图5所示，在闪烁体31两端安装光电倍增管(PMT)或硅光电倍增器(SiPM)等光子计数器51，宇宙射线粒子(例如缪子)穿过闪烁体31时产生的荧光光子在PMT的光阴极上产生光电子(即带电粒子)，电子在两个电极之间受电场作用下不断加速，倍增后产生更多的电子，电子汇聚形成的电流经过负载电阻后以电压信号输出。
闪烁体36可以具有与闪烁体31相同的结构和配置，在此不再赘述。
返回结合参照图3和图4，第一漂移管组32可以包括第一漂移管层321、第二漂移管层322、第三漂移管层323和第四漂移管层324。第一漂移管层321可以包括沿第一方向(在图示的实施例中，第一方向为X方向)布置的多个漂移管600，第二漂移管层322也包括沿第一方向布置的多个漂移管600。第三漂移管层323可以包括沿第二方向(在图示的实施例中，第二方向为Y方向)布置的多个漂移管600，第四漂移管层324也包括沿第二方向布置的多个漂移管600。
图6示出了根据本公开实施例的漂移管的示意图，其中例如缪子的宇宙射线粒子穿过所述漂移管。漂移管600可以包括用作阴极的金属管601和用作阳极的金属丝602，金属丝602位于金属管601的中央位置并且沿金属管601的轴向方向延伸。金属管601内填充有气体，例如3个大气压的氩和二氧化碳的混合气体。在工作时，可以施加约+2～3kV的高压给金属丝602，并且使金属管601接地，以使得金属丝601与金属管602之间形成高压静电场。当例如缪子的宇宙射线粒子穿过漂移管600时，宇宙射线粒子与气体原子相互作用，导致许多例如电子610的带电粒子朝着带正电的阳极金属丝602漂移。
例如，金属管601可以为铝管，其内径为30mm；金属丝602可以为镀金钨丝，其直径为约50μm。按照漂移管600的设计，在所选用的气体和电场条件下，电子610在漂移管中的漂移速度为设计值，例如，为30μm/ns。漂移速度乘以漂移时间，即可以得到漂移距离。由于漂移速度为设计值，即其为一定值，所以，可以预先建立的漂移管的漂移时间-漂移距离关系。而且电子610的漂移距离由宇宙射线粒子穿过漂移管600的位置决定，通过计算出的漂移距离，可以确定宇宙射线粒子穿过漂移管600的位置。当宇宙射线粒子穿过多个漂移管600的位置均被确定出来时，可以重建宇宙射 线粒子的径迹。
具体地，当电子610碰撞金属丝602时，可以记录该碰撞发生的时刻T 1，另外还可以确定宇宙射线粒子开始进入所述漂移管600的时间零点T 0，那么，漂移时间ΔT 1＝T 1-T 0。根据预先建立的漂移管的漂移时间-漂移距离关系，可以计算出漂移距离。
在较短时间范围内，能够同时被相隔一定距离的两层、三层或数层宇宙射线粒子探测器接收的粒子即是同一个宇宙射线粒子，记这种相隔一定距离的两层、三层或数层探测器为一组。例如，上述的宇宙射线粒子探测器110、130。通过电子学系统例如数据采集装置记录接收到粒子的位置、接收时间和能量等，通过接收时间差分析，计算粒子行走径迹和作用位置。例如，将不同探测器很短时间(如1纳秒)内接收到的两个粒子认为是属于相同的来源。此外，通过一组探测器可以确定粒子的入射径迹，通过被检查物体另一侧的一组探测器可以确定粒子的出射径迹，从而基于入射径迹和出射径迹确定被检查物体对宇宙射线作用的位置和散射角度。
图7示意性示出了宇宙射线粒子穿过根据本公开实施例的探测器。在图7中，示出了宇宙射线粒子P依次穿过探测器的闪烁体31、第一漂移管层321、第二漂移管层322。为了方便描述，定义闪烁体31位于Z＝Z 0的平面内，第一漂移管层321位于Z＝Z 1的平面内，第二漂移管层322位于Z＝Z 2的平面内。
在本公开的实施例中，宇宙射线粒子P以近似光速的速度穿过探测器，即，可以认为，宇宙射线粒子P开始穿过闪烁体31、第一漂移管层321、第二漂移管层322的时刻非常接近。具体地，漂移时间一般为微秒量级，从宇宙射线粒子进入探测器到闪烁体31产生电子学响应的时间约为几纳秒，此时间对微秒量级的漂移时间而言足够短，因此，可以将闪烁体31产生电子学响应的时刻作为真实的时间零点，即，可以将闪烁体31产生电子学响应的时刻作为时间零点T 0。同时，记录闪烁体31上的响应位置在X轴上的坐标值，例如为X 0。
在较短时间范围内，对于某一个宇宙射线粒子，第一漂移管层321中的一个漂移管600和第二漂移管层322中的一个漂移管600会产生响应。可以记录第一漂移管层321中的产生响应的漂移管600的编号为ID 1X，响应的时刻为T 1；以及记录第二漂移管层322中的产生响应的漂移管600的编号为ID 2X，响应的时刻为T 2。
然后，可以计算漂移时间。在编号为ID 1X的漂移管600中，漂移时间ΔT 1＝T 1-T 0；以及在编号为ID 2X的漂移管600中，漂移时间ΔT 2＝T 2-T 0。根据预先建立的漂移时间-漂移距离关系，得到对应的漂移距离分别为r 1和r 2。同时，根据编号为ID 1X、ID 2X的 漂移管600与中心位置的对应关系，得到编号为ID 1X、ID 2X的漂移管600的中心位置(例如漂移管的中心轴线)在X轴上的坐标值X ID1和X ID2。
在确定宇宙射线粒子P入射至漂移管600的位置之后，可以进行线性拟合步骤，以拟合出宇宙射线粒子P的径迹。如图所示，可以分别以编号为ID 1X、ID 2X的漂移管600的中心位置为圆心，以漂移距离r 1和r 2为半径，画出漂移圆(图中虚线圆形示出)。将宇宙射线粒子径迹与漂移圆的切点位置分别映射至Z＝Z 1和Z＝Z 2的平面上，分别得到两组对称的位置，即4个位置，该4个位置在X轴上的坐标值分别为：X ID1±r 1/cosθ和X ID2±r 2/cosθ，其中，θ为宇宙射线粒子径迹与垂直方向的夹角。在平面内，两个点可以确定一条直线。因此，位于Z＝Z 1平面上的两个位置与位于Z＝Z 2的平面上的两个位置可以两两组合形成4条直线，如图所示的直线L1、L2、L3和L4。
4条直线L1、L2、L3和L4中只有一条是真实的径迹，在根据本公开的实施例中，可以执行位置筛选步骤：延长直线至闪烁体所在的Z＝Z 0的平面，并选择最接近位置X 0且误差范围在预设范围内的直线，如图所示的直线L1，作为宇宙射线粒子的真实径迹。以此方式，重建了宇宙射线粒子的径迹。
在本公开的实施例中，将漂移管和闪烁体组合，有助于获取重建宇宙射线粒子径迹所需的真实时间零点，以挑选出最符合实际情况的径迹，从而可以更准确地重建宇宙射线粒子径迹。
在上述实施例中，通过漂移时间确定漂移距离之后，可以不直接确定宇宙射线粒子径迹与漂移圆的切线方向，如图7中虚线径迹为干扰径迹。在未设置闪烁体的纯漂移管系统中，需要遍历所有分布情况，找出线性拟合度最佳的一组。在本公开的实施例中，加入一层闪烁体后，通过宇宙射线粒子在闪烁体上的作用位置(例如上述的位置X 0)，不需要闪烁体31具有很高的空间分辨力，可以容易地筛选出真实的径迹，而且准确率高，大大简化了数据处理流程。
在上面的描述中，详细描述了宇宙射线粒子的径迹在XZ平面内的重建方法，应该理解的是，可以根据宇宙射线粒子P依次穿过探测器的闪烁体31、第三漂移管层323、第四漂移管层324的示例来重建宇宙射线粒子在YZ平面内的径迹，所述重建方法可以与上述在XZ平面内的重建方法相同，在此不再赘述。
因此，根据第一组宇宙射线粒子探测器110探测的数据，并且基于上面的重建方法，可以重建宇宙射线粒子在XZ和YZ平面内的径迹，从而可以重建宇宙射线粒子P在空间坐标系中入射至被检查物体120的入射径迹。
类似地，根据第二组宇宙射线粒子探测器130探测的数据，并且基于上面的重建方法，可以重建宇宙射线粒子在XZ和YZ平面内的径迹，从而可以重建宇宙射线粒子P在空间坐标系中通过被检查物体120后出射的出射径迹。
在根据本公开实施例的重建宇宙射线粒子径迹的方法中，每一组探测器均包括闪烁体与漂移管的组合，通过加入闪烁体，既可以提供漂移管定位所需的宇宙射线粒子入射的时间零点，又有助于挑选出最符合真实情况的径迹。
在本公开的实施例中，通过重建宇宙射线粒子P入射至被检查物体120的入射径迹以及穿过被检查物体120后出射的出射径迹，可以确定出宇宙射线粒子P穿过被检查物体120后的散射角度，而散射角度分布和物质的原子序数存在对应关系，可以基于事先建立的散射角度分布与各种原子序数的物质之间的对应关系或者分类曲线，确定被检查物体120中的材料属性。
参照图12，所述宇宙射线粒子探测器110、130还可以包括计算装置180。即，根据本公开实施例的宇宙射线粒子探测器可以包括：至少一个闪烁体31、36，用于测量宇宙射线粒子入射至所述设备的时间零点；多个漂移管600，所述多个漂移管被配置为：在所述宇宙射线粒子作用下，所述多个漂移管中的至少2个漂移管中的带电粒子产生漂移；和计算装置180。例如，所述计算装置180可以包括存储器181和处理器182，所述存储器181上存储有指令，当所述指令被所述处理器182执行时实现以下步骤：根据所述时间零点，计算所述至少2个漂移管中带电粒子的漂移时间；基于计算出的漂移时间，确定宇宙射线粒子入射至所述至少2个漂移管的位置；和根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置，拟合出宇宙射线粒子的径迹。
相应地，根据本公开实施例的所述宇宙射线粒子探测器可以视为一种用于重建宇宙射线粒子的径迹的设备。所述用于重建宇宙射线粒子的径迹的设备可以包括计算装置180，所述计算装置180可以包括存储器181和处理器182，所述存储器181上存储有指令，当所述指令被所述处理器182执行时实现根据本公开实施例的用于重建宇宙射线粒子的径迹的方法。
进一步地，根据本公开实施例的检查设备可以包括用于重建宇宙射线粒子的径迹的设备和控制装置(例如图1中所示的控制器140)。所述控制装置可以包括存储器和处理器，所述存储器上存储有指令，当所述指令被所述处理器执行时实现根据本公开实施例的检查方法。
应该理解，检查设备包括的控制装置的存储器和处理器可以分别与用于重建宇宙 射线粒子的径迹的设备包括的计算装置的存储器和处理器集成在一起。当然，在其他实施例中，控制装置的存储器和处理器可以分别独立于计算装置的存储器和处理器设置。也就是说，本公开实施例对存储器和处理器的设置方式并不作特别的限制。
在上述实施例中，在被检查物体120的顶面和底面各布置一组探测器110、130，每组探测器110、130含有三个平行超层，即闪烁体所在超层和2个漂移管组所在超层，每个漂移管组包括4个漂移管层，以获取X轴、Y轴位置。具体地，在4个漂移管层组成的漂移管组中，使用两层漂移管(例如漂移管层321、322)测量X轴位置，使用另两层漂移管(例如漂移管层323、324)测量Y轴位置，从而可以避免漂移管管壁或管间空隙造成探测效率的损失。在其它实施例中，一个漂移管组可以包括少于4层的漂移管，例如，一个漂移管组可以包括2层漂移管，其中一层漂移管用于测量X轴位置，另一层漂移管用于测量Y轴位置；一个漂移管组可以包括多于4层的漂移管，例如，一个漂移管组可以包括6层漂移管，其中三层漂移管用于测量X轴位置，另三层漂移管用于测量Y轴位置。
在本公开的实施例中，漂移管层中的漂移管可以采用稀疏排列，从而有效降低制造成本。
如图8A和图8B所示，分别示出了漂移管紧密排列和稀疏排列的示意图。每个漂移管的半径为R，漂移管层的总长度为L。在紧密排列的情况下，如图8A所示，所需的漂移管数量为N 1＝L/2R。在稀疏排列的情况下，相邻两层漂移管连线的水平角为α(0°＜α＜60°)，所需的漂移管数量为N 2＝L/(4R·cosα)。所以，稀疏排列所需的漂移管数量约为紧密排列所需的漂移管数量的1/(2cosα)。当α＝30°时，可节约42.26％的漂移管；当α＝45°时，可节约29.29％的漂移管。在上述实施例中，漂移管的布置可覆盖所有入射角的宇宙射线粒子，可以在节约漂移管数量的情况下不影响整体探测效率。
可选地，还可将探测器组分别设置于被检查物体的两侧，甚至前后面，采用多面探测器测量方式，如四组(上下面、两侧面)、六组(上下面、两侧面、前后面)等。如图9A所示，探测器组包括上探测器910，下探测器911，左探测器912，右探测器913，前探测器915和后探测器914，分布在被检查物体120的周围。为增加粒子探测的效率，还可以采用上下面水平或倾斜、两侧探测器与地面保持一定角度(呈外张的U型排布)的探测器布置。
在其他实施例中，为了提高检查效率，让被检查物体120快速通过扫描通道，可以在行走方向上使用连续的大面积探测器，以获得足够多的粒子信息。记被检查物体 120进入通道入口的时刻为t1，离开出口的时刻为t2，车辆总长为1，车速保持v米/秒左右，通道总长度约为(t2-t1)·v。此外，还可采用小面积探测器或分段式探测器对被检查物体的指定区域进行停车检查，如图9B、图9C和图9D所示。将被检查物体120停至测量区域，进行检查。例如可疑物121正好在小面积的上探测器920和小面积的下探测器921之间的位置，从而方便检查。
如图9C和9D所示，小面积探测器921或分段式底面探测器922、923和924可埋于地下，被检查物体的可疑区域121正好位于顶面探测器920和底面探测器921中间。也可使底面探测器922，923和924凸出在地面上，正好被车轮部分隔开。采用这种小面积或分段式探测器虽然可能采集数据量不及连续的大面积探测器完整，但是可降低探测器设计、系统搭建和维修的难度，简化系统结构，减少软硬件成本。
在一些实施例中，采用连续大面积位置灵敏探测器检测运动车辆的轨迹。由于车辆在检查通道中运动，因此需要采用监控设备150记录车辆的行驶轨迹，以便与探测器探测到的宇宙射线粒子位置进行符合。常规的方法有视频定位、光路定位和压力传感等。由于车辆缓慢前行，路线近似直线，对监控设备150的要求无需过高。如采用多摄像头进行视频跟踪时，仅需顶视摄像头即可满足定位要求。在其他实施例中，在采用光路定位时，仅需在车辆一侧放置一列光路即可。
根据本公开的实施例，扫描过程中产生的大量数据可通过无线传输或光缆、网线等线路传输到后端的数据处理工作站。相比无线方式，推荐采用有线传输方式，其不但可以保证数据传输的速度，降低信号在传输过程中的损失，提高信号传输的抗干扰能力，还可以在很大程度上降低数据采集的技术难度和成本。
另一方面，本公开的实施例可以提供一种用于重建宇宙射线粒子的径迹的方法，如图10所示，所述方法可以包括以下步骤：
S101、控制宇宙射线粒子穿过宇宙射线粒子探测器，所述宇宙射线粒子探测器包括至少一个闪烁体和多个漂移管，使得所述多个漂移管中的至少2个漂移管中的带电粒子漂移；
S102、利用所述至少一个闪烁体，记录宇宙射线粒子入射至所述宇宙射线粒子探测器的时间零点；
S103、根据所述时间零点，计算所述至少2个漂移管中带电粒子的漂移时间；
S104、基于计算出的漂移时间，确定宇宙射线粒子入射至所述至少2个漂移管的位置；和
S105、根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置，拟合出宇宙射线粒子的径迹。
结合参照图6，上述方法还可以包括：响应于至少2个漂移管600中的带电粒子的漂移，输出至少2个漂移响应信号；和记录产生至少2个漂移响应信号的至少2个响应时刻。
可选地，上述步骤S104可以具体包括：分别计算所述至少2个响应时刻与所述时间零点的差值，将所述差值分别作为所述至少2个漂移管中带电粒子的漂移时间。
结合参照图5，可选地，上述步骤S102可以具体包括：响应于宇宙射线粒子P入射至至少一个闪烁体31，输出至少一个闪烁体响应信号；和记录产生所述至少一个闪烁体响应信号的闪烁体响应时刻，将该闪烁体响应时刻确定为所述时间零点。
结合参照图7，上述方法还可以包括：利用至少一个闪烁体31，测量宇宙射线粒子入射至闪烁体31的位置，例如图7中的位置X 0。
可选地，上述步骤S105可以具体包括：根据确定出的宇宙射线粒子入射至至少2个漂移管的位置(例如，图7中示出的位置)以及测量出的宇宙射线粒子入射至闪烁体31的位置(例如图7中的位置X 0)，拟合出宇宙射线粒子P的径迹。
根据另一方面，本公开的实施例还提供一种检查方法，如图11所示，所述检查方法可以包括以下步骤：
S111、例如利用上述的宇宙射线粒子探测器，探测入射至被检查物体的宇宙射线粒子和从被检查物体出射的宇宙射线粒子，所述宇宙射线粒子探测器包括至少一个闪烁体和多个漂移管；
S112、重建入射至被检查物体的宇宙射线粒子的入射径迹；
S113、重建从被检查物体出射的宇宙射线粒子的出射径迹；
S114、基于所述入射径迹和所述出射径迹，计算宇宙射线粒子在被检查物体作用下的散射特性值；和
S115、利用所述散射特性值，识别所述被检查物体的材料属性。
在步骤S112和S113中，可以利用上文描述的重建方法重建所述入射径迹和所述出射径迹。
可选地，闪烁体31、36可以适用于纳秒(ns)量级的时间测量，这样，宇宙射线粒子以光速穿过闪烁体时，其穿过探测区域的时间也是纳秒量级，可以利用闪烁体31、36直接测量宇宙射线粒子的传播时间，从而直接计算获得宇宙射线粒子的动量。
可选地或附加地，闪烁体31、36的输出脉冲幅值与入射的宇宙射线粒子的动量成正比，通过测量闪烁体31、36的输出脉冲幅值，也可以计算出宇宙射线粒子的动量。考虑到脉冲幅值实际测量准确度的问题，还可以将宇宙射线粒子的动量分为多级，例如，将宇宙射线粒子的动量分级记录为(ΔE，2ΔE，…，NΔE)。
以此方式，通过利用闪烁体获取宇宙射线粒子的动量，然后将该动量用于宇宙射线成像与物质识别参数的计算，从而可以有效提高检查系统的识别效果。
这样，根据本公开实施例的检查方法还可以包括：利用所述至少一个闪烁体，测量宇宙射线粒子的平均动量。
可选地，上述步骤S114可以具体包括：
计算所述入射径迹与所述出射径迹之间的散射角度；
计算散射角度的均方根；和
基于所述均方根和所述平均动量，计算宇宙射线粒子在被检查物体作用下的散射特性值。
具体地，可以利用下面的散射密度(scattering density)计算公式，来计算散射特性值：
Figure PCTCN2019103057-appb-000002
其中，σ θ为散射角度的均方根，p为入射粒子的平均动量，L为被检查物体120被宇宙射线粒子穿过的材料的厚度。例如，将不同探测器很短时间(如1纳秒)内接收到的两个粒子认为是属于相同的来源。此外，通过第一组探测器可以确定粒子的入射径迹，通过被检查物体另一侧的一组探测器可以确定粒子的出射径迹，从而基于入射径迹和出射径迹确定被检查物体对宇宙射线作用的位置和散射角度。再如，上述的平均动量可以根据闪烁体的探测值计算得到。
在此基础上，还可以利用下面的阻挡能力计算公式，计算阻挡能力值：
Figure PCTCN2019103057-appb-000003
其中，N scatter/(a scatter·t scatter)表示在t scatter时间内a scatter成像面积或体积上探测到的与物质发生散射作用的粒子个数N scatter，N stop/(a stop·t stop)表示在t stop时间内a stop成像面 积或体积上与物质发生阻挡作用的粒子个数N stop，p为入射粒子的平均动量，L为被检查物体120被宇宙射线粒子穿过的材料的厚度。若某个粒子在短时间内同时被入射探测器探测和出射探测器接收，则认为是散射粒子；若进入测量区，但仅在入射探测器探测，出射探测器没有接收信息，则认为是被阻挡粒子。
可选地，在一些实施例中，所述检查方法可以包括以下步骤：利用计算的阻挡能力值对低Z区进行材料属性分辨。例如，通过事先测量的一些物质的阻挡能力值与原子序数之间的对应表，通过查表的方式确定感兴趣区域的原子序数，从而确定材料属性。
以上的详细描述通过使用示意图、流程图和/或示例，已经阐述了检查设备和检查方法的众多实施例。在这种示意图、流程图和/或示例包含一个或多个功能和/或操作的情况下，本领域技术人员应理解，这种示意图、流程图或示例中的每一功能和/或操作可以通过各种结构、硬件、软件、固件或实质上它们的任意组合来单独和/或共同实现。在一个实施例中，本公开的实施例所述主题的若干部分可以通过专用集成电路(ASIC)、现场可编程门阵列(FPGA)、数字信号处理器(DSP)、或其他集成格式来实现。然而，本领域技术人员应认识到，这里所公开的实施例的一些方面在整体上或部分地可以等同地实现在集成电路中，实现为在一台或多台计算机上运行的一个或多个计算机程序(例如，实现为在一台或多台计算机系统上运行的一个或多个程序)，实现为在一个或多个处理器上运行的一个或多个程序(例如，实现为在一个或多个微处理器上运行的一个或多个程序)，实现为固件，或者实质上实现为上述方式的任意组合，并且本领域技术人员根据本公开，将具备设计电路和/或写入软件和/或固件代码的能力。此外，本领域技术人员将认识到，本公开所述主题的机制能够作为多种形式的程序产品进行分发，并且无论实际用来执行分发的信号承载介质的具体类型如何，本公开所述主题的示例性实施例均适用。信号承载介质的示例包括但不限于：可记录型介质，如软盘、硬盘驱动器、紧致盘(CD)、数字通用盘(DVD)、数字磁带、计算机存储器等；以及传输型介质，如数字和/或模拟通信介质(例如，光纤光缆、波导、有线通信链路、无线通信链路等)。
虽然已参照几个典型实施例描述了本公开，但应当理解，所用的术语是说明和示例性、而非限制性的术语。由于本公开能够以多种形式具体实施而不脱离发明的精神或实质，所以应当理解，上述实施例不限于任何前述的细节，而应在随附权利要求所 限定的精神和范围内广泛地解释，因此落入权利要求或其等效范围内的全部变化和改型都应为随附权利要求所涵盖。

Claims (21)

  1. 一种用于重建宇宙射线粒子的径迹的方法，包括以下步骤：
    利用宇宙射线粒子探测器探测宇宙射线粒子，所述宇宙射线粒子探测器包括至少一个闪烁体和多个漂移管，在所述宇宙射线粒子的作用下，所述多个漂移管中的至少2个漂移管中的带电粒子产生漂移；
    利用所述至少一个闪烁体，记录宇宙射线粒子入射至所述宇宙射线粒子探测器的时间零点；
    根据所述时间零点，计算所述至少2个漂移管中带电粒子的漂移时间；
    基于计算出的漂移时间，确定宇宙射线粒子入射至所述至少2个漂移管的位置；和
    根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置，拟合出宇宙射线粒子的径迹。
  2. 根据权利要求1所述的方法，还包括：
    响应于所述至少2个漂移管中的带电粒子的漂移，输出至少2个漂移响应信号；和
    记录产生所述至少2个漂移响应信号的至少2个响应时刻，
    其中，根据所述时间零点，计算所述至少2个漂移管中带电粒子的漂移时间，包括：
    分别计算所述至少2个响应时刻与所述时间零点的差值，将所述差值分别作为所述至少2个漂移管中带电粒子的漂移时间。
  3. 根据权利要求1所述的方法，其中，所述利用所述至少一个闪烁体，记录宇宙射线粒子入射至所述宇宙射线粒子探测器的时间零点的步骤包括：
    响应于所述宇宙射线粒子入射至所述至少一个闪烁体，输出至少一个闪烁体响应信号；和
    记录产生所述至少一个闪烁体响应信号的闪烁体响应时刻，将该闪烁体响应时刻确定为所述时间零点。
  4. 根据权利要求1-3中任一项所述的方法，还包括：利用所述至少一个闪烁体，测量宇宙射线粒子入射至所述闪烁体的位置，
    其中，所述根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置，拟合出宇宙射线粒子的径迹的步骤包括：
    根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置以及测量出的宇宙射线粒子入射至所述闪烁体的位置，拟合出宇宙射线粒子的径迹。
  5. 根据权利要求1-3中任一项所述的方法，其中，所述基于计算出的漂移时间，确定宇宙射线粒子入射至所述至少2个漂移管的位置的步骤包括：
    基于预先建立的漂移时间与漂移距离之间的对应关系，确定所述至少2个漂移管中的带电粒子的漂移距离；和
    基于所述漂移距离，确定宇宙射线粒子入射至所述至少2个漂移管的位置。
  6. 根据权利要求5所述的方法，还包括：确定所述至少2个漂移管的编号；和根据所述编号，确定所述至少2个漂移管中每一个的中心位置，
    其中，所述基于所述漂移距离，确定宇宙射线粒子入射至所述至少2个漂移管的位置的步骤包括：
    基于所述漂移距离和所述中心位置，确定宇宙射线粒子入射至所述至少2个漂移管的位置。
  7. 一种检查方法，包括以下步骤：
    利用宇宙射线粒子探测器探测入射至被检查物体的宇宙射线粒子和从被检查物体出射的宇宙射线粒子，所述宇宙射线粒子探测器包括至少一个闪烁体和多个漂移管；
    利用根据权利要求1-6中任一项所述的方法，重建入射至被检查物体的宇宙射线粒子的入射径迹；
    利用根据权利要求1-6中任一项所述的方法，重建从被检查物体出射的宇宙射线粒子的出射径迹；
    基于所述入射径迹和所述出射径迹，计算宇宙射线粒子在被检查物体作用下的散射特性值；和
    利用所述散射特性值，识别所述被检查物体的材料属性。
  8. 根据权利要求7所述的检查方法，还包括：利用所述至少一个闪烁体，测量宇宙射线粒子的平均动量。
  9. 根据权利要求8所述的检查方法，其中，所述基于所述入射径迹和所述出射径迹，计算宇宙射线粒子在被检查物体作用下的散射特性值的步骤包括：
    计算所述入射径迹与所述出射径迹之间的散射角度；
    计算散射角度的均方根；和
    基于所述均方根和所述平均动量，计算宇宙射线粒子在被检查物体作用下的散射特性值。
  10. 根据权利要求9所述的检查方法，其中，所述基于所述均方根和所述平均动量，计算宇宙射线粒子在被检查物体作用下的散射特性值的步骤包括：通过下式计算散射特性值：
    Figure PCTCN2019103057-appb-100001
    其中，σ θ为散射角度的均方根，p为入射粒子的平均动量，L为所述被检查物体被宇宙射线粒子穿过的材料的厚度。
  11. 一种用于重建宇宙射线粒子的径迹的设备，包括：
    至少一个闪烁体，用于测量宇宙射线粒子入射至所述设备的时间零点；
    多个漂移管，所述多个漂移管被配置为：在所述宇宙射线粒子作用下，所述多个漂移管中的至少2个漂移管中的带电粒子产生漂移；和
    计算装置，所述计算装置包括存储器和处理器，所述存储器上存储有指令，当所述指令被所述处理器执行时实现以下步骤：
    根据所述时间零点，计算所述至少2个漂移管中带电粒子的漂移时间；
    基于计算出的漂移时间，确定宇宙射线粒子入射至所述至少2个漂移管的位置；和
    根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置，拟合出宇宙射线粒子的径迹。
  12. 根据权利要求11所述的设备，其中，所述多个漂移管包括：
    位于至少2个第一漂移管层且沿第一方向布置的多个第一漂移管；和
    位于至少2个第二漂移管层且沿不同于第一方向的第二方向布置的多个第二漂移管。
  13. 根据权利要求12所述的设备，其中，位于同一个第一漂移管层中的2个相邻的第一漂移管的中心位置之间的距离大于第一漂移管的直径。
  14. 根据权利要求11-13中任一项所述的设备，其中，
    所述多个漂移管还被配置为：响应于所述至少2个漂移管中的带电粒子的漂移，输出至少2个漂移响应信号；和
    记录产生所述至少2个漂移响应信号的至少2个响应时刻，以及
    其中，根据所述时间零点，计算所述至少2个漂移管中带电粒子的漂移时间，包括：
    分别计算所述至少2个响应时刻与所述时间零点的差值，将所述差值分别作为所述至少2个漂移管中带电粒子的漂移时间。
  15. 根据权利要求11-13中任一项所述的设备，其中，所述至少一个闪烁体被配置为：
    响应于所述宇宙射线粒子入射至所述至少一个闪烁体，输出至少一个闪烁体响应信号；和
    记录产生所述至少一个闪烁体响应信号的闪烁体响应时刻，将该闪烁体响应时刻确定为所述时间零点。
  16. 根据权利要求11-13中任一项所述的设备，其中，所述至少一个闪烁体还用于测量宇宙射线粒子入射至所述闪烁体的位置，以及
    其中，根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置，拟合出宇宙射线粒子的径迹包括：
    根据确定出的宇宙射线粒子入射至所述至少2个漂移管的位置以及测量出的宇宙 射线粒子入射至所述闪烁体的位置，拟合出宇宙射线粒子的径迹。
  17. 根据权利要求11-13中任一项所述的设备，其中，基于计算出的漂移时间，确定宇宙射线粒子入射至所述至少2个漂移管的位置，包括：
    基于预先建立的漂移时间与漂移距离之间的对应关系，确定所述至少2个漂移管中的带电粒子的漂移距离；和
    基于所述漂移距离，确定宇宙射线粒子入射至所述至少2个漂移管的位置。
  18. 根据权利要求11所述的设备，其中，当所述指令被所述处理器执行时还实现以下步骤：确定所述至少2个漂移管的编号；和根据所述编号，确定所述至少2个漂移管中每一个的中心位置，以及
    其中，基于所述漂移距离，确定宇宙射线粒子入射至所述至少2个漂移管的位置，包括：
    基于所述漂移距离和所述中心位置，确定宇宙射线粒子入射至所述至少2个漂移管的位置。
  19. 一种检查设备，包括：
    第一宇宙射线粒子探测器，设置在被检查物体的第一侧，用于重建入射至被检查物体的宇宙射线粒子的入射径迹；和
    第二宇宙射线粒子探测器，设置在被检查物体的与所述第一侧相对的第二侧，用于重建从被检查物体出射的宇宙射线粒子的出射径迹，
    其中，所述第一宇宙射线粒子探测器和所述第二宇宙射线粒子探测器中的至少一个为根据权利要求11-18中任一项所述的设备。
  20. 根据权利要求19所述的检查设备，还包括：控制装置，所述控制装置包括存储器和处理器，所述存储器上存储有指令，当所述指令被所述处理器执行时实现以下步骤：
    基于所述入射径迹和所述出射径迹，计算宇宙射线粒子在被检查物体作用下的散射特性值；和
    利用所述散射特性值，识别所述被检查物体的材料属性。
  21. 根据权利要求20所述的检查设备，其中，当所述指令被所述处理器执行时，还实现根据权利要求8-10中任一项所述的检查方法。
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