Muon scattering tomography is believed to be a promising technique for cargo container inspection, owing to the ability of natural muons to penetrate into dense materials and the absence of artificial radiation. In th...Muon scattering tomography is believed to be a promising technique for cargo container inspection, owing to the ability of natural muons to penetrate into dense materials and the absence of artificial radiation. In this work, the material discrimination ability of muon scattering tomography is evaluated based on experiments at the Tsinghua University cosmic ray muon tomography facility,with four materials: flour(as drugs substitute), aluminum,steel, and lead. The features of the different materials could be discriminated with cluster analysis and classifiers based on support vector machine. The overall discrimination precisions for these four materials could reach 70, 95, and 99% with 1-, 5-, and 10-min-long measurement,respectively.展开更多
Muon tomography is a capable imaging technique to measure the geometry of high-Z objects. However,most existed algorithms used in muon tomography have obscured the effects of angular distribution and momentum spectra ...Muon tomography is a capable imaging technique to measure the geometry of high-Z objects. However,most existed algorithms used in muon tomography have obscured the effects of angular distribution and momentum spectra of cosmic ray muons and reduced the spatial resolution. We present a modified multi-group model that takes into account these effects and calibrates the model by the material of lead. Performance tests establish that the model is capable of measuring the thickness of a Pb slab and identifying the material of an unknown slab on a reasonable exposure timescale, in both cases of complete and incomplete angular data. Results show that the modified multi-group model is helpful for improvements in image resolution in real applications.展开更多
Purpose To study the cosmic ray muon tomographic imaging of high-Z material with Micromegas-based tracking system.Method A high-spatial-resolution tracking system was set up with the micro-mesh gaseous structure(Micro...Purpose To study the cosmic ray muon tomographic imaging of high-Z material with Micromegas-based tracking system.Method A high-spatial-resolution tracking system was set up with the micro-mesh gaseous structure(Micromegas)detec-tors in order to study the muon tomographic imaging technique.Six layers of 90 mm×90 mm one-dimensional readout Micromegas were used to construct a tracking system.Result and conclusion The imaging test using some metallic bars was performed with cosmic ray muons.A two-dimensional imaging of the test object was presented with a newly proposed ratio algorithm.The result of this work shows that the ratio algorithm is well performed.展开更多
Purpose The research focuses on the related designing and simulating the high-position-resolution trajectory detector system based on cosmic ray muon tomography.Methods The energy deposition of muon in the detector va...Purpose The research focuses on the related designing and simulating the high-position-resolution trajectory detector system based on cosmic ray muon tomography.Methods The energy deposition of muon in the detector varies with the length of the ionization path.Results The simulation of the submillimeter detector system was designed for muon imaging.The optimal position resolution of the detector reached 0.6 mm.Conclusions The entire research process includes the selection of analysis of parameters affecting system design,designing of two high-position-resolution detectors based on plastic scintillators,implementation of different imaging algorithms and image quality assessment based on different imaging models.It provides a solution based on high positional resolution plastic scintillator detectors for cosmic ray muon scattering imaging.展开更多
Muon tomography is a novel method for the non-destructive imaging of materials based on muon rays,which are highly penetrating in natural background radiation.Currently,the most commonly used imaging methods include m...Muon tomography is a novel method for the non-destructive imaging of materials based on muon rays,which are highly penetrating in natural background radiation.Currently,the most commonly used imaging methods include muon radiography and muon tomography.A previously studied method known as coinciding muon trajectory density tomography,which utilizes muonic secondary particles,is proposed to image low and medium atomic number(Z)materials.However,scattering tomography is mostly used to image high-Z materials,and coinciding muon trajectory density tomography exhibits a hollow phenomenon in the imaging results owing to the self-absorption effect.To address the shortcomings of the individual imaging methods,hybrid model tomography combining scattering tomography and coinciding muon trajectory density tomography is proposed and verified.In addition,the peak signal-to-noise ratio was introduced to quantitatively analyze the image quality.Different imaging models were simulated using the Geant4 toolkit to confirm the advantages of this innovative method.The simulation results showed that hybrid model tomography can image centimeter-scale materials with low,medium,and high Z simultaneously.For high-Z materials with similar atomic numbers,this method can clearly distinguish those with apparent differences in density.According to the peak signal-to-noise ratio of the analysis,the reconstructed image quality of the new method was significantly higher than that of the individual imaging methods.This study provides a reliable approach to the compatibility of scattering tomography and coinciding muon trajectory density tomography.展开更多
Muon tomography is a promising method in the detection and imaging of high Z material. In general, considering the quality of track reconstruction in imaging, a detector of good position resolution, high efficiency an...Muon tomography is a promising method in the detection and imaging of high Z material. In general, considering the quality of track reconstruction in imaging, a detector of good position resolution, high efficiency and large area is required. This paper presents the design and study of a prototype of position sensitive MRPC with 0.15 mm narrow gas gap and 2.54 mm strip readout. Through a cosmic-ray experiment, the performance of MRPC module is carefully observed and each channel is calibrated. Through an X ray experiment with a narrow slit, the position resolution is studied. The results show that the time resolution of the module can reach 61ps and the spatial resolution can reach 0.36 mm.展开更多
Introduction Cosmic-ray muon imaging is a kind of nondestructive detection technology which can be used to detect unknown objects in geological exploration,civil engineering and nuclear safety.Transmission imaging and...Introduction Cosmic-ray muon imaging is a kind of nondestructive detection technology which can be used to detect unknown objects in geological exploration,civil engineering and nuclear safety.Transmission imaging and scattering tomography schemes are studied.Method The transmission scheme uses a multilayer detector to measure the direction of a cosmic-ray muon passing through an object.The scattering scheme involves placing two detectors upstream and downstream of the object to record the incident and exit directions of the muon passing through the object.The effect of the detector resolution on the imaging clarity of transmission imaging was studied.The applicable scenarios of the two schemes were analyzed.Results The results by calculating show that in the transmission imaging of a hundred-meter object,a spatial resolution of 2.5 m can be achieved,and Cu and Fe can be discriminated with a density difference of 1.1 g/cm3.Scattering tomography is mainly suitable for meter-level objects,which can detect 0.2 m chamber and distinguish 0.05 m heavy metal blocks in rock.展开更多
Introduction Muon scattering tomography(MST)can be employed to scan cargo containers and vehicles for special nuclear materials by using cosmic muons.However,the flux of cosmic ray muons is relatively low for direct d...Introduction Muon scattering tomography(MST)can be employed to scan cargo containers and vehicles for special nuclear materials by using cosmic muons.However,the flux of cosmic ray muons is relatively low for direct detection.Thus,the detection has to be done in a short timescale with small numbers of muons to satisfy the demands of practical applications.Method In this paper,we propose an artificial neural network(ANN)algorithm for material discrimination using MST.The muon scattering angles were simulated using Geant4 to formulate the training set,and the muon scatter angles were measured by Micromegas detection system to create the test set.Results The ANN-based algorithm presented here ensures a discrimination accuracy of 98.0%between aluminum,copper and tungsten in a 5 min measurement of 4×4×4 cm^(3)blocks.展开更多
In this paper, a versatile time and charge measurement(MQT) board for muon tomography is described in detail. For time measurement, the general-purpose timeto-digital converter(TDC) chip TDC-GP2 is employed,while for ...In this paper, a versatile time and charge measurement(MQT) board for muon tomography is described in detail. For time measurement, the general-purpose timeto-digital converter(TDC) chip TDC-GP2 is employed,while for charge measurement, digitization plus numerical integration in field programmable gate array is employed.Electronic tests demonstrate that the total 32 channels of two MQT boards have a time resolution of superior than100 ps, with excellent linearity for time and charge measurement.展开更多
文摘Muon scattering tomography is believed to be a promising technique for cargo container inspection, owing to the ability of natural muons to penetrate into dense materials and the absence of artificial radiation. In this work, the material discrimination ability of muon scattering tomography is evaluated based on experiments at the Tsinghua University cosmic ray muon tomography facility,with four materials: flour(as drugs substitute), aluminum,steel, and lead. The features of the different materials could be discriminated with cluster analysis and classifiers based on support vector machine. The overall discrimination precisions for these four materials could reach 70, 95, and 99% with 1-, 5-, and 10-min-long measurement,respectively.
基金supported by the Science and Technology Development Foundation of CAEP(No.2015B0103014)the National Natural Science Foundation of China(No.11605163)
文摘Muon tomography is a capable imaging technique to measure the geometry of high-Z objects. However,most existed algorithms used in muon tomography have obscured the effects of angular distribution and momentum spectra of cosmic ray muons and reduced the spatial resolution. We present a modified multi-group model that takes into account these effects and calibrates the model by the material of lead. Performance tests establish that the model is capable of measuring the thickness of a Pb slab and identifying the material of an unknown slab on a reasonable exposure timescale, in both cases of complete and incomplete angular data. Results show that the modified multi-group model is helpful for improvements in image resolution in real applications.
基金supported by the Program of National Natural Science Foundation of China Grant No.11605197the Fundamental Research Funds for the Central Universitiesthe State Key Laboratory of Particle Detection and Electronics,SKLPDE-ZZ-201818,SKLPDE-KF-201912
文摘Purpose To study the cosmic ray muon tomographic imaging of high-Z material with Micromegas-based tracking system.Method A high-spatial-resolution tracking system was set up with the micro-mesh gaseous structure(Micromegas)detec-tors in order to study the muon tomographic imaging technique.Six layers of 90 mm×90 mm one-dimensional readout Micromegas were used to construct a tracking system.Result and conclusion The imaging test using some metallic bars was performed with cosmic ray muons.A two-dimensional imaging of the test object was presented with a newly proposed ratio algorithm.The result of this work shows that the ratio algorithm is well performed.
基金supported by the National Nat-ural Science Foundation of China(Grant No.U2067206 and No.U1932162)
文摘Purpose The research focuses on the related designing and simulating the high-position-resolution trajectory detector system based on cosmic ray muon tomography.Methods The energy deposition of muon in the detector varies with the length of the ionization path.Results The simulation of the submillimeter detector system was designed for muon imaging.The optimal position resolution of the detector reached 0.6 mm.Conclusions The entire research process includes the selection of analysis of parameters affecting system design,designing of two high-position-resolution detectors based on plastic scintillators,implementation of different imaging algorithms and image quality assessment based on different imaging models.It provides a solution based on high positional resolution plastic scintillator detectors for cosmic ray muon scattering imaging.
基金supported by the National Natural Science Foundation of China(No.11875163)Natural Science Foundation of Hunan Province(Nos.2021JJ20006 and 2021JJ40444)+1 种基金Ministry of Science and Technology of China(No.2020YFE0202001)Department of Education of Hunan Province(Nos.19B488 and 21A0281)。
文摘Muon tomography is a novel method for the non-destructive imaging of materials based on muon rays,which are highly penetrating in natural background radiation.Currently,the most commonly used imaging methods include muon radiography and muon tomography.A previously studied method known as coinciding muon trajectory density tomography,which utilizes muonic secondary particles,is proposed to image low and medium atomic number(Z)materials.However,scattering tomography is mostly used to image high-Z materials,and coinciding muon trajectory density tomography exhibits a hollow phenomenon in the imaging results owing to the self-absorption effect.To address the shortcomings of the individual imaging methods,hybrid model tomography combining scattering tomography and coinciding muon trajectory density tomography is proposed and verified.In addition,the peak signal-to-noise ratio was introduced to quantitatively analyze the image quality.Different imaging models were simulated using the Geant4 toolkit to confirm the advantages of this innovative method.The simulation results showed that hybrid model tomography can image centimeter-scale materials with low,medium,and high Z simultaneously.For high-Z materials with similar atomic numbers,this method can clearly distinguish those with apparent differences in density.According to the peak signal-to-noise ratio of the analysis,the reconstructed image quality of the new method was significantly higher than that of the individual imaging methods.This study provides a reliable approach to the compatibility of scattering tomography and coinciding muon trajectory density tomography.
基金Supported by National Natural Science Foundation of China(11035002,11020101059,10775082,11275108)
文摘Muon tomography is a promising method in the detection and imaging of high Z material. In general, considering the quality of track reconstruction in imaging, a detector of good position resolution, high efficiency and large area is required. This paper presents the design and study of a prototype of position sensitive MRPC with 0.15 mm narrow gas gap and 2.54 mm strip readout. Through a cosmic-ray experiment, the performance of MRPC module is carefully observed and each channel is calibrated. Through an X ray experiment with a narrow slit, the position resolution is studied. The results show that the time resolution of the module can reach 61ps and the spatial resolution can reach 0.36 mm.
文摘Introduction Cosmic-ray muon imaging is a kind of nondestructive detection technology which can be used to detect unknown objects in geological exploration,civil engineering and nuclear safety.Transmission imaging and scattering tomography schemes are studied.Method The transmission scheme uses a multilayer detector to measure the direction of a cosmic-ray muon passing through an object.The scattering scheme involves placing two detectors upstream and downstream of the object to record the incident and exit directions of the muon passing through the object.The effect of the detector resolution on the imaging clarity of transmission imaging was studied.The applicable scenarios of the two schemes were analyzed.Results The results by calculating show that in the transmission imaging of a hundred-meter object,a spatial resolution of 2.5 m can be achieved,and Cu and Fe can be discriminated with a density difference of 1.1 g/cm3.Scattering tomography is mainly suitable for meter-level objects,which can detect 0.2 m chamber and distinguish 0.05 m heavy metal blocks in rock.
基金supported by the Program of National Natural Science Foundation of China Grant Nos.11805168 and 21805251
文摘Introduction Muon scattering tomography(MST)can be employed to scan cargo containers and vehicles for special nuclear materials by using cosmic muons.However,the flux of cosmic ray muons is relatively low for direct detection.Thus,the detection has to be done in a short timescale with small numbers of muons to satisfy the demands of practical applications.Method In this paper,we propose an artificial neural network(ANN)algorithm for material discrimination using MST.The muon scattering angles were simulated using Geant4 to formulate the training set,and the muon scatter angles were measured by Micromegas detection system to create the test set.Results The ANN-based algorithm presented here ensures a discrimination accuracy of 98.0%between aluminum,copper and tungsten in a 5 min measurement of 4×4×4 cm^(3)blocks.
基金supported by the National Natural Science Foundation of China(No.11005108)
文摘In this paper, a versatile time and charge measurement(MQT) board for muon tomography is described in detail. For time measurement, the general-purpose timeto-digital converter(TDC) chip TDC-GP2 is employed,while for charge measurement, digitization plus numerical integration in field programmable gate array is employed.Electronic tests demonstrate that the total 32 channels of two MQT boards have a time resolution of superior than100 ps, with excellent linearity for time and charge measurement.
