Method, device and system for inspecting moving object based on cosmic rays

Patent metadata

Field	Value
Publication number	US-10620336-B2
Application number	US-201715411359-A
Country	US
Kind code	B2
Filing date	Jan 20, 2017
Priority date	Jan 22, 2016
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

The present disclosure relates to a method, a device and a system for inspecting a moving object based on cosmic rays, pertaining to the field of radiation imaging and safety inspection techniques. The method includes: detecting whether a speed of the inspected moving object is within a preset range; recording a motion trajectory of the moving object with a monitoring device; acquiring information about charged particles in the cosmic rays with a position sensitive detector, the information about charged particles including track information of the charged particles; determining the moving object by matching positions of the motion trajectory and the track information; reconstructing the track of the charged particles according to the information about the charged particles; and recognizing the material inside the moving object based on the track reconstruction.

First claim

What is claimed is:

1. A method for inspecting a moving object based on cosmic rays, comprising:
detecting whether a speed of the inspected moving object is within a preset range;
recording a motion trajectory of the moving object with a monitoring device, the monitoring device comprises combination of any one or more of: a thermal imager, a camera, a pressure sensor, and an optical sensor; and
acquiring information about charged particles in the cosmic rays with a position sensitive detector, the information about charged particles comprising track information of the charged particles;
determining the moving object by matching positions of the motion trajectory and the track information;
reconstructing the track of the charged particles according to the information about the charged particles; and
recognizing the material inside the moving object based on the track reconstruction, wherein the determining the moving object by matching positions of the motion trajectory and the track information comprises:
analyzing a time difference between an incident time and an emission time of the track information of the charged particles, wherein the track information of the charged particles comprised in the information about charged particles and information of the moving object are iteratively updated in real time; and
matching the time and position of the track information of the charged particles and the motion trajectory of the moving object according to an incident position, an emission position of the track information of the charged particles and the analyzed time difference.

2. The method of claim 1 , wherein the preset range of the speed of the moving object is selected to ensure that at least one charged particle can be detected from per 100 square centimeters of a surface area of the moving object.

3. The method of claim 1 , wherein the position sensitive detector is configured to have a capability of detecting muons and electrons from the cosmic rays;
the position sensitive detector is configured to have a capability of detecting a material with a medium-to-high atomic number which is higher than the atomic number of aluminum, and a material with a low atomic number which is lower than the atomic number of aluminum, and
the material with a low atomic number is recognized based on a blocking effect to electrons; and
the material with a medium-to-high atomic number is recognized based on a scattering effect to muons.

4. The method of claim 1 , wherein the position sensitive detector comprises a GEM detector, an MRPC detector, a drift chamber or a drift tube array; and the position sensitive detector is configured as a part of the system for inspecting a moving vehicle, the position sensitive detector is placed in an inspection channel, and a vehicle to be inspected passes through the position sensitive detector.

5. The method of claim 3 , wherein reconstructing the track of the charged particles according to the information about the charged particles comprises:
calculating a parameter Ratio of the material according to the track information of the charged particles, estimating an initial value of an atomic number and an initial value of a relative mass of the material, the parameter Ratio denoting a ratio of a scattering parameter of the material on the charged particles against a blocking parameter of the material on the charged particles;
calculating a radiation length according to a relationship among the initial value of the atomic number and the initial value of the relative mass and the radiation length;
obtaining a thickness of the material according to the radiation length;
calculating a blocking parameter and a scattering parameter of the material according to the initial value of the atomic number, the initial value of the relative mass and the thickness of the material; and
recognizing the material with the blocking parameter and the scattering parameter, a material with a low atomic number being recognized based on a blocking effect to electrons in the charged particles; and a material with a medium-to-high atomic number being recognized based on a scattering effect to muons in the charged particles.

6. The method of claim 5 , wherein the method further comprises: reconstructing a material distribution map with an imaging algorithm according to a corresponding relationship among the blocking parameter, the scattering parameter and the material property, the imaging algorithm comprising a PoCA algorithm and/or a MLSD-OSEM algorithm.

7. The method of claim 5 , wherein the method further comprises: updating information about the material to perform a next iterative process.

8. The method of claim 5 , wherein the method further comprises: determining a category characteristic of the material of the moving object according to a corresponding relationship among the scattering parameter, the blocking parameter and the material property, and recognizing the material with a non-parametric test method.

9. The method of claim 1 , wherein multiple pieces of track information of the charged particles are processed in parallel during the reconstruction of the track;
the track information of the charged particles comprises an incident time, an incident position and an incident direction, an emission time, an emission position and an emission direction of the charged particles; and determining the moving object by matching positions of the motion trajectory and the track information comprises:
analyzing a time difference between the incident time and the emission time; and
matching the time and position of the track information of the charged particles and the motion trajectory of the moving object according to the incident position, the emission position and the analyzed time difference.

10. A device for inspecting a moving object based on cosmic rays, comprising a hardware processor configured to implement:
a speed detection module configured to detect whether a speed of the inspected moving object is within a preset range;
a recording module configured to record a motion trajectory of the inspected moving object with a monitoring device, wherein the monitoring device comprises combination of any one or more of: a thermal imager, a camera, a pressure sensor, and an optical sensor;
an acquiring module configured to acquire information about charged particles in the cosmic rays with a position sensitive detector, the information about charged particles comprising track information of the charged particles, wherein the track information of the charged particles comprised in the information about charged particles and information of the moving object are iteratively updated in real time;
a matching module configured to determine the moving object by matching positions of the motion trajectory and the track information;
a reconstruction module configured to reconstruct the track of the charged particles according to the information about the charged particles; and
a recognition module configured to recognize the material inside the moving object based on the track reconstruction,
wherein the matching module is further configured to:
analyze a time difference between an incident time and an emission time of the track information of the charged particles; and
match the time and position of the track information of the charged particles and the motion trajectory of the moving object according to an incident position, an emission position of the track information of the charged particles and the analyzed time difference.

11. The device of claim 10 , wherein the position sensitive detector is configured to have a capability of detecting muons and electrons from the cosmic rays.

Assignees

• Univ Tsinghua
• Nuctech Co Ltd

Inventors

• Kang Kejun
• Cheng Jianping
• Chen Zhiqiang
• Zhao Ziran
• Li Junli
• Wang Xuewu
• Zeng Zhi
• Zhang Qingjun
• Gu Jianping
• Yi Xi
• Liu Bicheng
• Xu Guangming
• Wang Yongqiang

Classifications

• G01T5/02

  Processing of tracks; Analysis of tracks · CPC title

• G01N2223/205

  natural source · CPC title

• G01V5/0016

  Physics · mapped topic

• G01V5/0075 Primary

  Physics · mapped topic

• G01V5/0091

  Physics · mapped topic