The propagation of the fast muon population mainly due to collisional effect in a dense deuterium-tritium （DT for short） mixture is investigated and analysed within the framework of the relativistic Fokker Planck eq...The propagation of the fast muon population mainly due to collisional effect in a dense deuterium-tritium （DT for short） mixture is investigated and analysed within the framework of the relativistic Fokker Planck equation. Without the approximation that the muons propagate straightly in the DT mixture, the muon penetration length, the straggling length, and the mean transverse dispersion radius are calculated for different initial energies, and especially for different densities of the densely compressed DT mixture in our suggested muon-driven fast ignition （FI）. Unlike laser-driven FI requiring super-high temperature, muons can catalyze DT fusion at lower temperatures and may generate an ignition sparkle before the self-heating fusion follows. Our calculation is important for the feasibility and the experimental study of muon-driven FI.展开更多
This study aimed to investigate the relationship between atmospheric conditions and cosmic ray (CR) muons using daily and monthly CR data collected by the KAAU muon detector in Jeddah, Saudi Arabia between 2007 and 20...This study aimed to investigate the relationship between atmospheric conditions and cosmic ray (CR) muons using daily and monthly CR data collected by the KAAU muon detector in Jeddah, Saudi Arabia between 2007 and 2012. Specifically, the study examined the effects of atmospheric pressure, air temperature, and relative humidity on CR muons at different time scales (annual, seasonal, and monthly). The results of the analysis revealed that atmospheric pressure and air temperature had a negative impact on CR muons, while relative humidity had a positive impact. Although air temperature and relative humidity had small mean values across all time scales, their coefficients varied significantly from month to month and season to season. In addition, the study conducted multivariable correlation analyses for each day, which showed that pressure coefficients had consistently negative mean values, while the temperature and humidity coefficients had varying effects, ranging from positive to negative values. The reasons for the variations in the coefficients are not yet fully understood, but the study proposed several possible terrestrial and extraterrestrial explanations. These findings provide important insights into the complex interactions between the Earth’s atmosphere and cosmic rays, which can contribute to a better understanding of the potential impacts of cosmic rays on the Earth’s climate and environment.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
The Taishan Antineutrino Observatory(TAO)experiment features a top veto tracker system comprising 160 modules,each constructed from plastic scintillator(PS)strips,embedded wavelength shifting fibers(WLS-fibers),and si...The Taishan Antineutrino Observatory(TAO)experiment features a top veto tracker system comprising 160 modules,each constructed from plastic scintillator(PS)strips,embedded wavelength shifting fibers(WLS-fibers),and silicon photomultipliers.This article reports on the performance of all produced modules,focusing on the production and readout/trigger design,and providing insights into scintillation detectors based on WLS-fibers.Three types of trigger modes and their efficiencies were defined to comprehensively evaluate the performance of this unique design,which was verified through batch production,comprehensive measurement strategies,and quality inspection methods.In“module”mode,the detection(tagging)efficiency of the PS exceeded 99.67%at a 30-photoelectron threshold,and even in“AND”mode,it surpassed 99.60%at a 15-photoelectron threshold.The muon tagging efficiency satisfies the requirements of TAO.The production and performance of PS modules establish a benchmark for other experiments,with optimized optical fiber arrangements that enhance light yield and muon detection efficiency.展开更多
Demand for fast-charging lithium-ion batteries(LIBs)has escalated incredibly in the past few years.A conventional method to improve the performance is to chemically partly substitute the transition metal with another ...Demand for fast-charging lithium-ion batteries(LIBs)has escalated incredibly in the past few years.A conventional method to improve the performance is to chemically partly substitute the transition metal with another to increase its conductivity.In this study,we have chosen to investigate the lithium diffusion in doped anatase(TiO_(2))anodes for high-rate LIBs.Substitutional doping of TiO_(2)with the pentavalent Nb has previously been shown to increase the high-rate performances of this anode material dramatically.Despite the conventional belief,we explicitly show that Nb is mobile and diffusing at room temperature,and different diffusion mechanisms are discussed.Diffusing Nb in TiO_(2)has staggering implications concerning most chemically substituted LIBs and their performance.While the only mobile ion is typically asserted to be Li,this study clearly shows that the transition metals are also diffusing,together with the Li.This implies that a method that can hinder the diffusion of transition metals will increase the performance of our current LIBs even further.展开更多
We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of muonic atoms.For ions with nuclear charges Z≥24,transitions from low-ly...We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of muonic atoms.For ions with nuclear charges Z≥24,transitions from low-lying excited states to the 1s-muon state can lead to the production of electron-positron pairs.We show that the Breit interaction determines the transition probabilities for states with nonzero orbital momentum.We show that the pair production arises mainly from the decay of the 2p states.Thus,the Breit interaction governs electron-positron pair production in bound-bound muon transitions.This process offers a unique opportunity to explore quantum electrodynamics in strong fields,as well as a class of nonradiative transitions involving electron-positron pair production.展开更多
A new muon beam facility,called the Experimental Muon Source(EMuS),was proposed for construction at the China Spallation Neutron Source(CSNS).The design of the complex muon beamlines for the EMuS baseline scheme,which...A new muon beam facility,called the Experimental Muon Source(EMuS),was proposed for construction at the China Spallation Neutron Source(CSNS).The design of the complex muon beamlines for the EMuS baseline scheme,which is based on superconducting solenoids,superferric dipoles and room-temperature magnets,is presented herein.Various muon beams,including surface muons,decay muons and low energy muons,have been developed for multipurpose applications.The optics design and simulation results of the trunk beamline and branch beamlines are presented.With a proton beam power of 25 kW at a standalone target station that consists of a conical graphite target and high-field superconducting solenoids,the muon beam intensity in the trunk beamline varies from 10^(7)/s for surface muons to 10^(10)/s for high-momentum decay muons.And at the endstations,these values vary from 10^(5)/s for surface muons to 10^(8)/s for decay muons.展开更多
The muonic component of the extensive air showers (EAS) is of great importance for the astroparticle physics. It carries the information about the properties of primary cosmic ray (CR) particles, such as their mass, a...The muonic component of the extensive air showers (EAS) is of great importance for the astroparticle physics. It carries the information about the properties of primary cosmic ray (CR) particles, such as their mass, and electromagnetic and hadronic nature. It provides a sensitive test for the hadronic interaction models, which are inevitable for describing the cascade shower development of cosmic rays in EAS experiments. The YangBaJing Hybrid Array (YBJ-HA) experiment has been in operation since the end of 2016. Surface detectors are used for the measurements of primary energy, angular direction and core position of a shower event, while underground muon detectors are used for measuring the density of muons at various locations. Using the data obtained by the YBJ-HA experiment,this work reports the first measurement of the lateral muon distribution for the primary cosmic ray energy in the 100TeV region. The punch-through effect is evaluated via MC simulation.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
Muons produced by a short pulse laser can serve as a new type of muon source having potential advantages of high intensity, small source emittance, short pulse duration and low cost. To validate it in experiments, a s...Muons produced by a short pulse laser can serve as a new type of muon source having potential advantages of high intensity, small source emittance, short pulse duration and low cost. To validate it in experiments, a suitable muon diagnostics system is needed since high muon flux generated by a short pulse laser shot is always accompanied by high radiation background, which is quite different from cases in general muon researches. A detection system is proposed to distinguish muon signals from radiation background by measuring the muon lifetime. It is based on the scintillator detector with water and lead shields, in which water is used to adjust energies of muons stopped in the scintillator and lead to against radiation background. A Geant 4 simulation on the performance of the detection system shows that efficiency up to 52% could be arrived for low-energy muons around 200 MeV and this efficiency decreases to 14% for high-energy muons above 1000 MeV. The simulation also shows that the muon lifetime can be derived properly by measuring attenuation of the scintilla light of electrons from muon decays inside the scintillator detector.展开更多
Gas electron multiplier （GEM） detectors have been used in cosmic muon scattering tomography and neutron imaging over the last decade. In this work, a triple GEM device with an effective readout area of 10 cm × ...Gas electron multiplier （GEM） detectors have been used in cosmic muon scattering tomography and neutron imaging over the last decade. In this work, a triple GEM device with an effective readout area of 10 cm × 10 cm is developed, and a method of discriminating between cosmic muons and X-rays based on rise time is tested. The energy resolution of the GEM detector is tested by 55Fe ray source to prove the GEM detector has a good performance. Analysis of the complete signal-cycles allows us to get the rise time and pulse heights. The experiment result indicates that cosmic muons and X-rays can be discriminated with an appropriate rise time threshold.展开更多
Through mean-field calculations,we demonstrate that,in a large Z nucleus binding multiple muons,these heavy leptons localize within a few dozen femtometers of the nucleus.The mutual Coulomb interactions between the mu...Through mean-field calculations,we demonstrate that,in a large Z nucleus binding multiple muons,these heavy leptons localize within a few dozen femtometers of the nucleus.The mutual Coulomb interactions between the muons and protons can lead to a substantial decrease in proton chemical potential,surpassing 1 MeV.These findings imply that,in principle,the proton-dripline can be expanded on the nuclear chart,suggesting the possible production of nuclei with Z around 120.展开更多
The inelastic scattering cross section for muons,μ^(-),with energies E=9-100 eV from the ^(229)Th nuclei is calculated in the framework of the second order of the perturbation theory for quantum electrodynamics.The d...The inelastic scattering cross section for muons,μ^(-),with energies E=9-100 eV from the ^(229)Th nuclei is calculated in the framework of the second order of the perturbation theory for quantum electrodynamics.The dominant contribution to the excitation of the low energy isomer ^(229m)Th(3/2^(+),8.19±0.12 eV)originates from the E2 multipole.The excitation cross section reaches the value of 10^(-21) cm^(2) in the range E≈10 eV.This value is four to five orders of magnitude larger than the electron excitation cross section and is sufficient for the efficient excitation of ^(229m)Th on the muon beam at the next generation of muon colliders.展开更多
We present the performance of the ALICE muon spectrometer for measuring the charm and beauty inclusive p t differential production cross sections via single muons and unlike-sign dimuons in proton-proton collisions at...We present the performance of the ALICE muon spectrometer for measuring the charm and beauty inclusive p t differential production cross sections via single muons and unlike-sign dimuons in proton-proton collisions at√ s = 14 TeV.展开更多
We investigate the resonant production of color octet muons in order to explore the discovery potential of Future Circular Collider（FCC）-based μp colliders.It is shown that the search potentials of μp colliders es...We investigate the resonant production of color octet muons in order to explore the discovery potential of Future Circular Collider（FCC）-based μp colliders.It is shown that the search potentials of μp colliders essentially surpass the potential of the LHC and would exceed that of the FCC pp collider.展开更多
Confined spaces such as polar regions, deep earth and deep ocean are crucial navigation scenarios where traditional navigation techniques have difficulty in obtaining external signals for positioning. The cosmic ray m...Confined spaces such as polar regions, deep earth and deep ocean are crucial navigation scenarios where traditional navigation techniques have difficulty in obtaining external signals for positioning. The cosmic ray muons, which carry the spatial and energetic information, are easy to penetrate these confined spaces. Therefore, the unique muon characteristic provides a new perspective to estimate detector position, which can be considered using in confined spaces navigation.In this paper, a well-developed theory of muon navigation is established by combining a muon pseudorange measurement method. Moreover, an Equivalent Velocity Calculation Model(EVCM)and a Muon Sequence Matching Technology(MSMT) are proposed. The first model corrects flight pseudorange error caused by the relativistic energy loss and the second technology compensates the random error in pseudorange measurement. Further, a series of simulations are performed to analyze the muon events number which can be received by detector in different scenarios with the variations of zenith angle, detector area, varied detector plates gap, and muon flight distance.Meanwhile, the simulation results demonstrate that the muon navigation update rate every 10 minutes can reach 5.989 in confined spaces at 100 m, and further pseudorange error analysis indicates that the meter-level positioning accuracy can be acquired. Finally, we construct a muon coincidence measurement scheme and verify that the laws of the muon positioning system for high-energy muons are consistent with the simulation results.展开更多
Cosmic-ray muons are highly penetrating background-radiation particles found in natural environments.In this study,we develop and test a plastic scintillator muon detector based on machine-learning algorithms.The dete...Cosmic-ray muons are highly penetrating background-radiation particles found in natural environments.In this study,we develop and test a plastic scintillator muon detector based on machine-learning algorithms.The detector underwent muon position-resolution tests at the Institute of Modern Physics in Lanzhou using a multiwire drift chamber(MWDC)experimental platform.In the simulation,the same structural and performance parameters were maintained to ensure the reliability of the simulation results.The Gaussian process regression(GPR)algorithm was used as the position-reconstruction algorithm owing to its optimal performance.The results of the Time Difference of Arrival algorithm were incorporated as one of the features of the GPR model to reconstruct the muon hit positions.The accuracy of the position reconstruction was evaluated by comparing the experimental results with Geant4 simulation results.In the simulation,large-area plastic scintillator detectors achieved a position resolution better than 20 mm.In the experimental-platform tests,the position resolutions of the test detectors were 27.9 mm.We also analyzed factors affecting the position resolution,including the critical angle of the total internal reflection of the photomultiplier tubes and distribution of muons in the MWDC.Simulations were performed to image both large objects and objects with different atomic numbers.The results showed that the system could image high-and low-Z materials in the constructed model and distinguish objects with significant density differences.This study demonstrates the feasibility of the proposed system,thereby providing a new detector system for muon-imaging applications.展开更多
It is the current belief of the Physics Community that neutrinos are bereft of Charge because of Conservation of Charge in decay processes such as Beta Decay and are point particles with no physical size or shape. It ...It is the current belief of the Physics Community that neutrinos are bereft of Charge because of Conservation of Charge in decay processes such as Beta Decay and are point particles with no physical size or shape. It is the purpose of this paper to calculate the charges and the size of the electron neutrino, the muon neutrino, and the tau neutrino based on data available of their rest masses using the charges and rest masses of the electron, muon, and tau leptons from the Standard Model of Particle Physics Table. We base our calculations on the premise that Energy can create both Mass and Charge. Charge by itself is not conserved in any process that produces neutrinos. Only Total Energy is conserved.展开更多
基金supported by the National Natural Science Foundation of China (Grant No 10675155)the National Basic Research of China (Grant No 2006CB806004)
文摘The propagation of the fast muon population mainly due to collisional effect in a dense deuterium-tritium （DT for short） mixture is investigated and analysed within the framework of the relativistic Fokker Planck equation. Without the approximation that the muons propagate straightly in the DT mixture, the muon penetration length, the straggling length, and the mean transverse dispersion radius are calculated for different initial energies, and especially for different densities of the densely compressed DT mixture in our suggested muon-driven fast ignition （FI）. Unlike laser-driven FI requiring super-high temperature, muons can catalyze DT fusion at lower temperatures and may generate an ignition sparkle before the self-heating fusion follows. Our calculation is important for the feasibility and the experimental study of muon-driven FI.
文摘This study aimed to investigate the relationship between atmospheric conditions and cosmic ray (CR) muons using daily and monthly CR data collected by the KAAU muon detector in Jeddah, Saudi Arabia between 2007 and 2012. Specifically, the study examined the effects of atmospheric pressure, air temperature, and relative humidity on CR muons at different time scales (annual, seasonal, and monthly). The results of the analysis revealed that atmospheric pressure and air temperature had a negative impact on CR muons, while relative humidity had a positive impact. Although air temperature and relative humidity had small mean values across all time scales, their coefficients varied significantly from month to month and season to season. In addition, the study conducted multivariable correlation analyses for each day, which showed that pressure coefficients had consistently negative mean values, while the temperature and humidity coefficients had varying effects, ranging from positive to negative values. The reasons for the variations in the coefficients are not yet fully understood, but the study proposed several possible terrestrial and extraterrestrial explanations. These findings provide important insights into the complex interactions between the Earth’s atmosphere and cosmic rays, which can contribute to a better understanding of the potential impacts of cosmic rays on the Earth’s climate and environment.
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 General Program of the National Natural Science Foundation of China(No.12075087)National Key Research and Development Program of China(No.2022YFA1602002)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA10011102)support from the Guangdong Provincial Key Laboratory of Advanced Particle Detection Technology。
文摘The Taishan Antineutrino Observatory(TAO)experiment features a top veto tracker system comprising 160 modules,each constructed from plastic scintillator(PS)strips,embedded wavelength shifting fibers(WLS-fibers),and silicon photomultipliers.This article reports on the performance of all produced modules,focusing on the production and readout/trigger design,and providing insights into scintillation detectors based on WLS-fibers.Three types of trigger modes and their efficiencies were defined to comprehensively evaluate the performance of this unique design,which was verified through batch production,comprehensive measurement strategies,and quality inspection methods.In“module”mode,the detection(tagging)efficiency of the PS exceeded 99.67%at a 30-photoelectron threshold,and even in“AND”mode,it surpassed 99.60%at a 15-photoelectron threshold.The muon tagging efficiency satisfies the requirements of TAO.The production and performance of PS modules establish a benchmark for other experiments,with optimized optical fiber arrangements that enhance light yield and muon detection efficiency.
基金supported by Vetenskapsrådet(2022-06217)supported by the Swedish Research Council(VR)through a Starting Grant(Dnr.2017-05078)+7 种基金M.M.through a Marie Sklodowska-Curie Action and the Swedish Research Council-VR(Dnr.2014-6426 and 2016-06955)Carl Tryggers Foundation for Scientific Research(CTS-18:272)supported by the Swedish Research Council(VR)through Grant 2022-06217the Foundation Blanceflor fellow scholarships for 2023 and 2024the Ruth and Nils-Erik Stenbäck Foundationthe funding from the Area of Advance-Material Sciences from Chalmers University of Technologysupported byÅForsk via the grant 22-378supported by the Japan Society for the Promotion Science(JSPS)KAKENHI Grant Nos.JP20K1149,JP23H01840 and JP24H00042.
文摘Demand for fast-charging lithium-ion batteries(LIBs)has escalated incredibly in the past few years.A conventional method to improve the performance is to chemically partly substitute the transition metal with another to increase its conductivity.In this study,we have chosen to investigate the lithium diffusion in doped anatase(TiO_(2))anodes for high-rate LIBs.Substitutional doping of TiO_(2)with the pentavalent Nb has previously been shown to increase the high-rate performances of this anode material dramatically.Despite the conventional belief,we explicitly show that Nb is mobile and diffusing at room temperature,and different diffusion mechanisms are discussed.Diffusing Nb in TiO_(2)has staggering implications concerning most chemically substituted LIBs and their performance.While the only mobile ion is typically asserted to be Li,this study clearly shows that the transition metals are also diffusing,together with the Li.This implies that a method that can hinder the diffusion of transition metals will increase the performance of our current LIBs even further.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1602501)the National Natural Science Foundation of China(Grant No.12011530060)+1 种基金supported solely by the Russian Science Foundation(Grant No.22-12-00043)supported by the Chinese Academy of Sciences(CAS)Presidents International Fellowship Initiative(PIFI)(Grant Nos.2018VMB0016 and 2022VMC0002),respectively。
文摘We explored a distinct mechanism for matter creation via electron-positron pair production during bound-bound transitions in the deexcitation of muonic atoms.For ions with nuclear charges Z≥24,transitions from low-lying excited states to the 1s-muon state can lead to the production of electron-positron pairs.We show that the Breit interaction determines the transition probabilities for states with nonzero orbital momentum.We show that the pair production arises mainly from the decay of the 2p states.Thus,the Breit interaction governs electron-positron pair production in bound-bound muon transitions.This process offers a unique opportunity to explore quantum electrodynamics in strong fields,as well as a class of nonradiative transitions involving electron-positron pair production.
基金supported by the National Natural Science Foundation of China(Nos.11527811 and 12035017).
文摘A new muon beam facility,called the Experimental Muon Source(EMuS),was proposed for construction at the China Spallation Neutron Source(CSNS).The design of the complex muon beamlines for the EMuS baseline scheme,which is based on superconducting solenoids,superferric dipoles and room-temperature magnets,is presented herein.Various muon beams,including surface muons,decay muons and low energy muons,have been developed for multipurpose applications.The optics design and simulation results of the trunk beamline and branch beamlines are presented.With a proton beam power of 25 kW at a standalone target station that consists of a conical graphite target and high-field superconducting solenoids,the muon beam intensity in the trunk beamline varies from 10^(7)/s for surface muons to 10^(10)/s for high-momentum decay muons.And at the endstations,these values vary from 10^(5)/s for surface muons to 10^(8)/s for decay muons.
基金Supported by National Key R&D Program of China(2018YFA0404202)National Natural Science Foundation of China(11635011,11761141001,11765019,11775233)
文摘The muonic component of the extensive air showers (EAS) is of great importance for the astroparticle physics. It carries the information about the properties of primary cosmic ray (CR) particles, such as their mass, and electromagnetic and hadronic nature. It provides a sensitive test for the hadronic interaction models, which are inevitable for describing the cascade shower development of cosmic rays in EAS experiments. The YangBaJing Hybrid Array (YBJ-HA) experiment has been in operation since the end of 2016. Surface detectors are used for the measurements of primary energy, angular direction and core position of a shower event, while underground muon detectors are used for measuring the density of muons at various locations. Using the data obtained by the YBJ-HA experiment,this work reports the first measurement of the lateral muon distribution for the primary cosmic ray energy in the 100TeV region. The punch-through effect is evaluated via MC simulation.
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 Science Challenge Project (No.JCKY2016212A505)the CAEP Foundation (No.2014A0102003)
文摘Muons produced by a short pulse laser can serve as a new type of muon source having potential advantages of high intensity, small source emittance, short pulse duration and low cost. To validate it in experiments, a suitable muon diagnostics system is needed since high muon flux generated by a short pulse laser shot is always accompanied by high radiation background, which is quite different from cases in general muon researches. A detection system is proposed to distinguish muon signals from radiation background by measuring the muon lifetime. It is based on the scintillator detector with water and lead shields, in which water is used to adjust energies of muons stopped in the scintillator and lead to against radiation background. A Geant 4 simulation on the performance of the detection system shows that efficiency up to 52% could be arrived for low-energy muons around 200 MeV and this efficiency decreases to 14% for high-energy muons above 1000 MeV. The simulation also shows that the muon lifetime can be derived properly by measuring attenuation of the scintilla light of electrons from muon decays inside the scintillator detector.
基金Supported by National Natural Science Foundation of China(11135002,11275235,11405077,11575073)
文摘Gas electron multiplier （GEM） detectors have been used in cosmic muon scattering tomography and neutron imaging over the last decade. In this work, a triple GEM device with an effective readout area of 10 cm × 10 cm is developed, and a method of discriminating between cosmic muons and X-rays based on rise time is tested. The energy resolution of the GEM detector is tested by 55Fe ray source to prove the GEM detector has a good performance. Analysis of the complete signal-cycles allows us to get the rise time and pulse heights. The experiment result indicates that cosmic muons and X-rays can be discriminated with an appropriate rise time threshold.
基金Supported by the Natural Science Foundation of China(11775099)。
文摘Through mean-field calculations,we demonstrate that,in a large Z nucleus binding multiple muons,these heavy leptons localize within a few dozen femtometers of the nucleus.The mutual Coulomb interactions between the muons and protons can lead to a substantial decrease in proton chemical potential,surpassing 1 MeV.These findings imply that,in principle,the proton-dripline can be expanded on the nuclear chart,suggesting the possible production of nuclei with Z around 120.
基金supported by a grant of the Russian Science Foundation(Project No 19-72-30014)。
文摘The inelastic scattering cross section for muons,μ^(-),with energies E=9-100 eV from the ^(229)Th nuclei is calculated in the framework of the second order of the perturbation theory for quantum electrodynamics.The dominant contribution to the excitation of the low energy isomer ^(229m)Th(3/2^(+),8.19±0.12 eV)originates from the E2 multipole.The excitation cross section reaches the value of 10^(-21) cm^(2) in the range E≈10 eV.This value is four to five orders of magnitude larger than the electron excitation cross section and is sufficient for the efficient excitation of ^(229m)Th on the muon beam at the next generation of muon colliders.
基金Supported by NSFC (10875051,10635020)State Key Development Program of Basic Research of China (2008CB317106)+1 种基金Key Project of Chinese Ministry of Education (306022,IRT0624)Programme of Introducing Talents of Discipline to Universitiesnder of China (B08033)
文摘We present the performance of the ALICE muon spectrometer for measuring the charm and beauty inclusive p t differential production cross sections via single muons and unlike-sign dimuons in proton-proton collisions at√ s = 14 TeV.
文摘We investigate the resonant production of color octet muons in order to explore the discovery potential of Future Circular Collider（FCC）-based μp colliders.It is shown that the search potentials of μp colliders essentially surpass the potential of the LHC and would exceed that of the FCC pp collider.
基金supported by the Young Scientists Fund, China (No. 62103021)。
文摘Confined spaces such as polar regions, deep earth and deep ocean are crucial navigation scenarios where traditional navigation techniques have difficulty in obtaining external signals for positioning. The cosmic ray muons, which carry the spatial and energetic information, are easy to penetrate these confined spaces. Therefore, the unique muon characteristic provides a new perspective to estimate detector position, which can be considered using in confined spaces navigation.In this paper, a well-developed theory of muon navigation is established by combining a muon pseudorange measurement method. Moreover, an Equivalent Velocity Calculation Model(EVCM)and a Muon Sequence Matching Technology(MSMT) are proposed. The first model corrects flight pseudorange error caused by the relativistic energy loss and the second technology compensates the random error in pseudorange measurement. Further, a series of simulations are performed to analyze the muon events number which can be received by detector in different scenarios with the variations of zenith angle, detector area, varied detector plates gap, and muon flight distance.Meanwhile, the simulation results demonstrate that the muon navigation update rate every 10 minutes can reach 5.989 in confined spaces at 100 m, and further pseudorange error analysis indicates that the meter-level positioning accuracy can be acquired. Finally, we construct a muon coincidence measurement scheme and verify that the laws of the muon positioning system for high-energy muons are consistent with the simulation results.
基金supported by the National Natural Science Foundation of China(Nos.12275120,11875163)Ministry of Science and Technology of China(No.2020YFE0202001)+1 种基金Science and Technology Innovation Program of Hunan Province(No.2022RC1202)Hunan Provincial Natural Science Foundation(No.2021JJ20006).
文摘Cosmic-ray muons are highly penetrating background-radiation particles found in natural environments.In this study,we develop and test a plastic scintillator muon detector based on machine-learning algorithms.The detector underwent muon position-resolution tests at the Institute of Modern Physics in Lanzhou using a multiwire drift chamber(MWDC)experimental platform.In the simulation,the same structural and performance parameters were maintained to ensure the reliability of the simulation results.The Gaussian process regression(GPR)algorithm was used as the position-reconstruction algorithm owing to its optimal performance.The results of the Time Difference of Arrival algorithm were incorporated as one of the features of the GPR model to reconstruct the muon hit positions.The accuracy of the position reconstruction was evaluated by comparing the experimental results with Geant4 simulation results.In the simulation,large-area plastic scintillator detectors achieved a position resolution better than 20 mm.In the experimental-platform tests,the position resolutions of the test detectors were 27.9 mm.We also analyzed factors affecting the position resolution,including the critical angle of the total internal reflection of the photomultiplier tubes and distribution of muons in the MWDC.Simulations were performed to image both large objects and objects with different atomic numbers.The results showed that the system could image high-and low-Z materials in the constructed model and distinguish objects with significant density differences.This study demonstrates the feasibility of the proposed system,thereby providing a new detector system for muon-imaging applications.
文摘It is the current belief of the Physics Community that neutrinos are bereft of Charge because of Conservation of Charge in decay processes such as Beta Decay and are point particles with no physical size or shape. It is the purpose of this paper to calculate the charges and the size of the electron neutrino, the muon neutrino, and the tau neutrino based on data available of their rest masses using the charges and rest masses of the electron, muon, and tau leptons from the Standard Model of Particle Physics Table. We base our calculations on the premise that Energy can create both Mass and Charge. Charge by itself is not conserved in any process that produces neutrinos. Only Total Energy is conserved.
