Active target time projection chambers are state-of-the-art tools in the field of low-energy nuclear physics and are particularly suitable for experiments using low-intensity radioactive ion beams or gamma rays.The Fu...Active target time projection chambers are state-of-the-art tools in the field of low-energy nuclear physics and are particularly suitable for experiments using low-intensity radioactive ion beams or gamma rays.The Fudan multi-purpose active target time projection chamber(fMeta-TPC)with 2048 channels was developed to studyα-clustering nuclei.This study focused on the photonuclear reaction with a laser Compton scattering gamma source,particularly for the decay of the highly excitedαcluster state.The design of fMeta-TPC is described in this paper.A comprehensive evaluation of its offline performance was conducted using an ultraviolet laser and ^(241)Amαsource.The results showed that the intrinsic angular resolution of the detector was within 0.30°,and the detector had an energy resolution of 6.85%for 3.0 MeVαparticles.The gain uniformity of the detector was approximately 10%(RMS/Mean),as tested by the ^(55)Fe X-ray source.展开更多
In recent years,the gap between the supply and demand of medical radioisotopes has increased,necessitating new methods for producing medical radioisotopes.Photonuclear reactions based on gamma sources have unique adva...In recent years,the gap between the supply and demand of medical radioisotopes has increased,necessitating new methods for producing medical radioisotopes.Photonuclear reactions based on gamma sources have unique advantages in terms of producing high specific activity and innovative medical radioisotopes.However,the lack of experimental data on reaction cross sections for photonuclear reactions of medical radioisotopes of interest has severely limited the development and production of photonuclear transmutation medical radioisotopes.In this study,the entire process of the generation,decay,and measurement of medical radioisotopes was simulated using online gamma activation and offline gamma measurements combined with a shielding gamma-ray spectrometer.Based on a quasi-monochromatic gamma beam from the Shanghai Laser Electron Gamma Source(SLEGS),the feasibility of this measurement of production cross section for surveyed medi-cal radioisotopes was simulated,and specific solutions for measuring medical radioisotopes with ultra-low production cross sections were provided.The feasibility of this method for high-precision measurements of the reaction cross section of medical radioisotopes was demonstrated.展开更多
In this study,we theoretically investigate the feasibility of using laser-wakefield accelerated(LWFA)electrons for the photonuclear measurement of nuclear isomers according to the characteristics of the electrons obta...In this study,we theoretically investigate the feasibility of using laser-wakefield accelerated(LWFA)electrons for the photonuclear measurement of nuclear isomers according to the characteristics of the electrons obtained from LWFA experiments conducted at the Compact Laser-Plasma Accelerator(CLAPA)laboratory.The experiments at the CLAPA show that a stable electron beam with an energy of 78-135 MeV and a charge of 300-600 pC can be obtained.The bremsstrahlung spectra were simulated using Geant4,which suggests that a bremsstrahlung source with a peak intensity of 10^(19) photons/s can be generated.Theoretical calculations of isomer production cross sections from the photonuclear reactions on six target nuclei,^(197)Au,^(180)Hf,^(159)Tb,^(115)In,^(103)Rh,and ^(90)Zr,were performed and compared with the available experimental data in EXFOR,which suggest that further experiments are required for a series of photonuclear reaction channels.Flux-averaged cross sections and isomer ratios(IR)resulting from such bremsstrahlung sources are theoretically deduced.The results suggest that IR measurements can be used to constrain nuclear components,such asγstrength function and optical model potential.In addition,the detection of the decay characteristics was evaluated with Geant4 simulations.The use of the LWFA electron beam and its bremsstrahlung for photonuclear studies involving nuclear isomers is anticipated.展开更多
Photonuclear reactions using a laser Compton scattering(LCS)gamma source provide a new method for producing radioisotopes for medical applications.Compared with the conventional method,this method has the advantages o...Photonuclear reactions using a laser Compton scattering(LCS)gamma source provide a new method for producing radioisotopes for medical applications.Compared with the conventional method,this method has the advantages of a high specific activity and less heat.Initiated by the Shanghai Laser Electron Gamma Source(SLEGS),we conducted a survey of potential photonuclear reactions,(γ,n),(γ,p),and(γ,γ')whose cross sections can be measured at SLEGS by summarising the experimental progress.In general,the data are rare and occasionally inconsistent.Therefore,theoretical calculations are often used to evaluate the production of medical radioisotopes.Subsequently,we verified the model uncertainties of the widely used reaction code TALYS-1.96,using the experimental data of the^(100)Mo(γ,n)^(99)Mo,^(65)Cu(γ,n)^(64)Cu,and^(68)Zn(γ,p)^(67)Cu reactions.展开更多
A photonuclear reaction transport model based on an isospin-dependent quantum molecular dynamics model （IQMD） is presented in the intermediate energy region, which is named as GiQMD in this study. Methodology to sim...A photonuclear reaction transport model based on an isospin-dependent quantum molecular dynamics model （IQMD） is presented in the intermediate energy region, which is named as GiQMD in this study. Methodology to simulate the course of the photonuclear reaction within the IQMD frame is described to study the photo- absorption cross section and π meson production, and the simulation results are compared with some available experimental data as well as the Giessen Boltzmann-Uehling-Uhlenbeck model.展开更多
For simulating more accurately neutron or proton production from photonuclear reactions,a data-based photonuclear reaction simulation algorithm has been developed.Reliable photonuclear cross sections from evaluated or...For simulating more accurately neutron or proton production from photonuclear reactions,a data-based photonuclear reaction simulation algorithm has been developed.Reliable photonuclear cross sections from evaluated or experimental database are chosen as input data.For checking the validity of the use of the data-based photonuclear algorithm,benchmarking simulations are presented in detail.We calculate photonuclear cross sections or reaction yield for ~9Be,^(48)Ti,^(133)Cs,and ^(197)Au and compare them with experimental data in the region of incident photon energy below ~30 MeV.While Geant4 can hardly reproduce photonuclear experimental data,results obtained from the data-based photonuclear algorithm are found in good agreement with experimental measurements.Potential application in estimation of specific activity of radioisotopes is further discussed.We conclude that the developed data-based photonuclear algorithm is suitable for an accurate prediction of photoninduced neutron or proton productions.展开更多
Relative yields were measured in the 40−130 MeV bremsstrahlung induced reactions of ^(59)Co.The experiments were performed with the beam from the electron linear accelerator LINAC-200 using the activation and off-line...Relative yields were measured in the 40−130 MeV bremsstrahlung induced reactions of ^(59)Co.The experiments were performed with the beam from the electron linear accelerator LINAC-200 using the activation and off-lineγ-ray spectrometric techniques.The bremsstrahlung photon flux was calculated with the Geant4 program.The cross sections were calculated by using the computer code TALYS-1.96 with different models and were found to be in good agreement with the experimental data.展开更多
Based on the facility of the Shanghai Laser Electron Gamma Source （SLEGS）, the transmutation for nuclear wastes such as 137^Cs and 129^I is investigated. It is found that nuclear waste can be transmuted efficiently ...Based on the facility of the Shanghai Laser Electron Gamma Source （SLEGS）, the transmutation for nuclear wastes such as 137^Cs and 129^I is investigated. It is found that nuclear waste can be transmuted efficiently via photonuclear reaction triggered by gamma photons generated from Compton backscattering between CO2 laser photons and 3.5 GeV electrons. The nuclear activities of 137^Cs and 129^I are evaluated and compared with the results of transmutation triggered by bremsstrahlung gamma photons driven by ultra intense laser. Due to the better character of gamma photon spectrum as well as the high brightness of gamma photons, the transmutation rate of Compton backscattering method is much higher than that of the bremsstrahlung method.展开更多
The flux-averaged cross-sections<σ(E_(γmax))>for the reactions^(65)Cu(γ,n)^(64)Cu,^(63)Cu(γ,n)^(62)Cu,^(63)Cu(γ,2n)^(61)Cu,and^(63)Cu(γ,3n)^(60)Cu have been measured within the bremsstrahlung end-point ene...The flux-averaged cross-sections<σ(E_(γmax))>for the reactions^(65)Cu(γ,n)^(64)Cu,^(63)Cu(γ,n)^(62)Cu,^(63)Cu(γ,2n)^(61)Cu,and^(63)Cu(γ,3n)^(60)Cu have been measured within the bremsstrahlung end-point energy E_(γmax)range of 35–94 MeV.The experiments were performed with the electron beam from the NSC KIPT linear accelerator LUE-40 with the use of the activation and off-lineγ-ray spectrometric techniques.Theoretical calculation of the flux-average cross-sections<σ(E_(γmax))>_(th)was conducted using the cross-sectionσ(E)values from the TALYS1.95 code,run with default options.It is shown that the experimental average cross-sections for the reactions^(65)Cu(γ,n)^(64)Cu,^(63)Cu(γ,n)^(62)Cu,and^(63)Cu(γ,2n)^(61)Cu are systematically higher than the theoretical estimates based on the TALYS1.95 code.The obtained<σ(E_(γmax))values supplement the data of different laboratories for the(γ,n)and(γ,2n)reactions of^(63)Cu and^(65)Cu.For the reaction^(63)Cu(γ,3n)^(60)Cu,the values of<σ(E_(γmax))>were measured for the first time.展开更多
Short-lived medical isotopes and their generators are typically produced in nuclear reactors and cyclotrons that require extensive facilities.However,considering the environmental concerns and economic costs of these ...Short-lived medical isotopes and their generators are typically produced in nuclear reactors and cyclotrons that require extensive facilities.However,considering the environmental concerns and economic costs of these traditional approaches,modern laser technology,which provides extremely strong electric fields within tabletop-sized areas,can serve as a potential supplementary method.Focusing specifically on the(γ,p)generation of the vital medical isotopes^(47)Sc and^(67)Cu,we used both experimental results and PIC-GEANT4 simulations to demonstrate that laser-induced photonuclear reaction is a promising method for isotope production.We developed a model capable of calculating isotope yields under various laser conditions and acceleration mechanisms.The findings revealed that a 200 TW laser can sufficiently produce diagnostic amounts of^(47)Sc and^(67)Cu,while simultaneously providing high specific activity,which is significant in medical applications for improving treatment efficacy,enhancing image resolution,and reducing side effects.展开更多
The^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-lineγ-ray spectrometric te...The^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-lineγ-ray spectrometric technique.The experimental isomeric yield ratio(IR)was determined for the reaction products^(95m,g)Nb at the bremsstrahlung end-point energy E_(γmax)range of 38-93 MeV.The obtained values of IR are in satisfactory agreement with the results of other studies and extend the range of previously known data.The theoretical values of the yields Y_(m,g)(E_(γmax))and the IR for the isomeric pair^(95m,g)Nb from the^(nat)Mo(γ,xnp)reaction were calculated using the partial cross-sectionsσ(E)from the TALYS1.95 code for six different level density models.For the investigated range of E_(γmax),the theoretical dependence of IR on energy was confirmed-the IR smoothly increases with increasing energy.The comparison showed a noticeable difference(more than 3.85 times)in the experimental IR relative to all theoretical estimates.展开更多
随着各种医用加速器新技术的提高和肿瘤患者数量的急剧增加,放射治疗已经成为治疗肿瘤的主要手段之一。医用加速器技术的不断进步,始终围绕着照射肿瘤的同时最大限度地保护正常器官而发展,但仍无法解决由于高能射线在治疗患者时所带来...随着各种医用加速器新技术的提高和肿瘤患者数量的急剧增加,放射治疗已经成为治疗肿瘤的主要手段之一。医用加速器技术的不断进步,始终围绕着照射肿瘤的同时最大限度地保护正常器官而发展,但仍无法解决由于高能射线在治疗患者时所带来的辐射污染。高能粒子产生的次级粒子如光子、光中子及质子等对人体组织产生的生物效应同样不可忽略,并逐渐受到重视和广泛的研究。由于加速器机头内部构造的金属元素为铅,靶区主要为钨,光子能量达到>7 Me V时,会超过光核反应阈值从而产生中子,这一反应称为光核反应。国外放疗机构对光中子产生的剂量开展了广泛研究。基于参与复杂相互作用的粒子特点,通过蒙特卡罗模拟和实验测量两个途径来研究医用加速器产生的光中子通量和能谱等物理量。由于医用加速器设计不同(主要是机头内部),性能也有很大差别,因此光中子的通量、能谱和剂量也有不同的分布规律。在文献评阅的基础上,从蒙特卡罗模拟和实验测量两个方面阐述目前对医用加速器产生光中子的研究现状以及放射治疗过程中的辐射防护和引发第二原发癌的物理因素。展开更多
基金supported by the National Key R&D Program of China(Nos.2022YFA1602402,2020YFE0202001,2023YFA1606900)the National Natural Science Foundation of China(NSFC)(Nos.12235003,11835002,11925502,11705031,12275053,12147101).
文摘Active target time projection chambers are state-of-the-art tools in the field of low-energy nuclear physics and are particularly suitable for experiments using low-intensity radioactive ion beams or gamma rays.The Fudan multi-purpose active target time projection chamber(fMeta-TPC)with 2048 channels was developed to studyα-clustering nuclei.This study focused on the photonuclear reaction with a laser Compton scattering gamma source,particularly for the decay of the highly excitedαcluster state.The design of fMeta-TPC is described in this paper.A comprehensive evaluation of its offline performance was conducted using an ultraviolet laser and ^(241)Amαsource.The results showed that the intrinsic angular resolution of the detector was within 0.30°,and the detector had an energy resolution of 6.85%for 3.0 MeVαparticles.The gain uniformity of the detector was approximately 10%(RMS/Mean),as tested by the ^(55)Fe X-ray source.
基金supported by the Strategic Priority Research Program of the CAS(No.XDB34030000)National Natural Science Foundation of China(No.11975210 and No.U1832129)+1 种基金National Key Research and Development Program of China(No.2022YFA1602404)Youth Innovation Promotion Association CAS(No.2017309).
文摘In recent years,the gap between the supply and demand of medical radioisotopes has increased,necessitating new methods for producing medical radioisotopes.Photonuclear reactions based on gamma sources have unique advantages in terms of producing high specific activity and innovative medical radioisotopes.However,the lack of experimental data on reaction cross sections for photonuclear reactions of medical radioisotopes of interest has severely limited the development and production of photonuclear transmutation medical radioisotopes.In this study,the entire process of the generation,decay,and measurement of medical radioisotopes was simulated using online gamma activation and offline gamma measurements combined with a shielding gamma-ray spectrometer.Based on a quasi-monochromatic gamma beam from the Shanghai Laser Electron Gamma Source(SLEGS),the feasibility of this measurement of production cross section for surveyed medi-cal radioisotopes was simulated,and specific solutions for measuring medical radioisotopes with ultra-low production cross sections were provided.The feasibility of this method for high-precision measurements of the reaction cross section of medical radioisotopes was demonstrated.
基金supported by the National Natural Science Foundation of China (Nos.11921006,U2230133)Beijing Outstanding Young Scientists Program+2 种基金National Grand Instrument Project (No.2019YFF01014400)National Key R&D Program of China (No.2022YFA1603303)Open Foundation of Key Laboratory of High Power Laser and Physics,Chinese Academy of Sciences (No.SGKF202104)。
文摘In this study,we theoretically investigate the feasibility of using laser-wakefield accelerated(LWFA)electrons for the photonuclear measurement of nuclear isomers according to the characteristics of the electrons obtained from LWFA experiments conducted at the Compact Laser-Plasma Accelerator(CLAPA)laboratory.The experiments at the CLAPA show that a stable electron beam with an energy of 78-135 MeV and a charge of 300-600 pC can be obtained.The bremsstrahlung spectra were simulated using Geant4,which suggests that a bremsstrahlung source with a peak intensity of 10^(19) photons/s can be generated.Theoretical calculations of isomer production cross sections from the photonuclear reactions on six target nuclei,^(197)Au,^(180)Hf,^(159)Tb,^(115)In,^(103)Rh,and ^(90)Zr,were performed and compared with the available experimental data in EXFOR,which suggest that further experiments are required for a series of photonuclear reaction channels.Flux-averaged cross sections and isomer ratios(IR)resulting from such bremsstrahlung sources are theoretically deduced.The results suggest that IR measurements can be used to constrain nuclear components,such asγstrength function and optical model potential.In addition,the detection of the decay characteristics was evaluated with Geant4 simulations.The use of the LWFA electron beam and its bremsstrahlung for photonuclear studies involving nuclear isomers is anticipated.
基金supported by the National Key R&D Program of China(No.2022YFA1602401)the National Natural Science Foundation of China(Nos.11961141004,U1832211,11922501,12325506)the National Basic Science Data Center‘Medical Physics DataBase’(No.NBSDC-DB-23)。
文摘Photonuclear reactions using a laser Compton scattering(LCS)gamma source provide a new method for producing radioisotopes for medical applications.Compared with the conventional method,this method has the advantages of a high specific activity and less heat.Initiated by the Shanghai Laser Electron Gamma Source(SLEGS),we conducted a survey of potential photonuclear reactions,(γ,n),(γ,p),and(γ,γ')whose cross sections can be measured at SLEGS by summarising the experimental progress.In general,the data are rare and occasionally inconsistent.Therefore,theoretical calculations are often used to evaluate the production of medical radioisotopes.Subsequently,we verified the model uncertainties of the widely used reaction code TALYS-1.96,using the experimental data of the^(100)Mo(γ,n)^(99)Mo,^(65)Cu(γ,n)^(64)Cu,and^(68)Zn(γ,p)^(67)Cu reactions.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11421505 and 11220101005the National Basic Research Program of China under Grant No 2014CB845401the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDB16
文摘A photonuclear reaction transport model based on an isospin-dependent quantum molecular dynamics model （IQMD） is presented in the intermediate energy region, which is named as GiQMD in this study. Methodology to simulate the course of the photonuclear reaction within the IQMD frame is described to study the photo- absorption cross section and π meson production, and the simulation results are compared with some available experimental data as well as the Giessen Boltzmann-Uehling-Uhlenbeck model.
基金supported by the National Natural Science Foundation of China(Nos.11405083 and 11675075)the Young Talent Project of the University of South Chinathe Extreme Light Infrastructure-Nuclear Physics(ELI-NP)-Phase I,a project co-financed by the European Union through the European Regional Development Fund
文摘For simulating more accurately neutron or proton production from photonuclear reactions,a data-based photonuclear reaction simulation algorithm has been developed.Reliable photonuclear cross sections from evaluated or experimental database are chosen as input data.For checking the validity of the use of the data-based photonuclear algorithm,benchmarking simulations are presented in detail.We calculate photonuclear cross sections or reaction yield for ~9Be,^(48)Ti,^(133)Cs,and ^(197)Au and compare them with experimental data in the region of incident photon energy below ~30 MeV.While Geant4 can hardly reproduce photonuclear experimental data,results obtained from the data-based photonuclear algorithm are found in good agreement with experimental measurements.Potential application in estimation of specific activity of radioisotopes is further discussed.We conclude that the developed data-based photonuclear algorithm is suitable for an accurate prediction of photoninduced neutron or proton productions.
基金Supported in part by the Ministry of Science and Higher Education of the Russian Federation (075-15-2021-1360)by the project of the National Center for Physics and Mathematics (NCPM)No.6“Nuclear and Radiation Physics,”direction 6.5.1。
文摘Relative yields were measured in the 40−130 MeV bremsstrahlung induced reactions of ^(59)Co.The experiments were performed with the beam from the electron linear accelerator LINAC-200 using the activation and off-lineγ-ray spectrometric techniques.The bremsstrahlung photon flux was calculated with the Geant4 program.The cross sections were calculated by using the computer code TALYS-1.96 with different models and were found to be in good agreement with the experimental data.
基金Knowledge Innovation Project of Chinese Academy of Sciences (KJCX2-SW-N13)China Postdoctoral ScienceFoundation, National Natural Science Foundation of China (10475108, 10605036, 10405032)+1 种基金One Hundred Person Project of SINAPShanghai Development Foundation for Science and Technology (06QA14062)
文摘Based on the facility of the Shanghai Laser Electron Gamma Source （SLEGS）, the transmutation for nuclear wastes such as 137^Cs and 129^I is investigated. It is found that nuclear waste can be transmuted efficiently via photonuclear reaction triggered by gamma photons generated from Compton backscattering between CO2 laser photons and 3.5 GeV electrons. The nuclear activities of 137^Cs and 129^I are evaluated and compared with the results of transmutation triggered by bremsstrahlung gamma photons driven by ultra intense laser. Due to the better character of gamma photon spectrum as well as the high brightness of gamma photons, the transmutation rate of Compton backscattering method is much higher than that of the bremsstrahlung method.
文摘The flux-averaged cross-sections<σ(E_(γmax))>for the reactions^(65)Cu(γ,n)^(64)Cu,^(63)Cu(γ,n)^(62)Cu,^(63)Cu(γ,2n)^(61)Cu,and^(63)Cu(γ,3n)^(60)Cu have been measured within the bremsstrahlung end-point energy E_(γmax)range of 35–94 MeV.The experiments were performed with the electron beam from the NSC KIPT linear accelerator LUE-40 with the use of the activation and off-lineγ-ray spectrometric techniques.Theoretical calculation of the flux-average cross-sections<σ(E_(γmax))>_(th)was conducted using the cross-sectionσ(E)values from the TALYS1.95 code,run with default options.It is shown that the experimental average cross-sections for the reactions^(65)Cu(γ,n)^(64)Cu,^(63)Cu(γ,n)^(62)Cu,and^(63)Cu(γ,2n)^(61)Cu are systematically higher than the theoretical estimates based on the TALYS1.95 code.The obtained<σ(E_(γmax))values supplement the data of different laboratories for the(γ,n)and(γ,2n)reactions of^(63)Cu and^(65)Cu.For the reaction^(63)Cu(γ,3n)^(60)Cu,the values of<σ(E_(γmax))>were measured for the first time.
文摘Short-lived medical isotopes and their generators are typically produced in nuclear reactors and cyclotrons that require extensive facilities.However,considering the environmental concerns and economic costs of these traditional approaches,modern laser technology,which provides extremely strong electric fields within tabletop-sized areas,can serve as a potential supplementary method.Focusing specifically on the(γ,p)generation of the vital medical isotopes^(47)Sc and^(67)Cu,we used both experimental results and PIC-GEANT4 simulations to demonstrate that laser-induced photonuclear reaction is a promising method for isotope production.We developed a model capable of calculating isotope yields under various laser conditions and acceleration mechanisms.The findings revealed that a 200 TW laser can sufficiently produce diagnostic amounts of^(47)Sc and^(67)Cu,while simultaneously providing high specific activity,which is significant in medical applications for improving treatment efficacy,enhancing image resolution,and reducing side effects.
文摘The^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-lineγ-ray spectrometric technique.The experimental isomeric yield ratio(IR)was determined for the reaction products^(95m,g)Nb at the bremsstrahlung end-point energy E_(γmax)range of 38-93 MeV.The obtained values of IR are in satisfactory agreement with the results of other studies and extend the range of previously known data.The theoretical values of the yields Y_(m,g)(E_(γmax))and the IR for the isomeric pair^(95m,g)Nb from the^(nat)Mo(γ,xnp)reaction were calculated using the partial cross-sectionsσ(E)from the TALYS1.95 code for six different level density models.For the investigated range of E_(γmax),the theoretical dependence of IR on energy was confirmed-the IR smoothly increases with increasing energy.The comparison showed a noticeable difference(more than 3.85 times)in the experimental IR relative to all theoretical estimates.
文摘随着各种医用加速器新技术的提高和肿瘤患者数量的急剧增加,放射治疗已经成为治疗肿瘤的主要手段之一。医用加速器技术的不断进步,始终围绕着照射肿瘤的同时最大限度地保护正常器官而发展,但仍无法解决由于高能射线在治疗患者时所带来的辐射污染。高能粒子产生的次级粒子如光子、光中子及质子等对人体组织产生的生物效应同样不可忽略,并逐渐受到重视和广泛的研究。由于加速器机头内部构造的金属元素为铅,靶区主要为钨,光子能量达到>7 Me V时,会超过光核反应阈值从而产生中子,这一反应称为光核反应。国外放疗机构对光中子产生的剂量开展了广泛研究。基于参与复杂相互作用的粒子特点,通过蒙特卡罗模拟和实验测量两个途径来研究医用加速器产生的光中子通量和能谱等物理量。由于医用加速器设计不同(主要是机头内部),性能也有很大差别,因此光中子的通量、能谱和剂量也有不同的分布规律。在文献评阅的基础上,从蒙特卡罗模拟和实验测量两个方面阐述目前对医用加速器产生光中子的研究现状以及放射治疗过程中的辐射防护和引发第二原发癌的物理因素。
