The energy response calibration of the commonly used high pressure ionization chamber is very difficult to obtain when the gamma-ray energy is more than 3 MeV. In order to get the calibration of the higher part of the...The energy response calibration of the commonly used high pressure ionization chamber is very difficult to obtain when the gamma-ray energy is more than 3 MeV. In order to get the calibration of the higher part of the high pressure ionization chamber, we use the Fluka Monte Carlo program to perform the energy response in both the spherical and the cylindrical high pressure ionization chamber which are full of argon gas. The results compared with prior study when the gamma-ray energy is less than 1.25 MeV. Our result of Monte Carlo calculation shows agreement with those obtained by measurement within the uncertainty of the respective methods. The calculation of this study is significant for the high pressure ionization chamber to measure the high energy gamma-ray.展开更多
放射性光子源如103Pd和125I已被广泛用于前列腺和眼睛的植入治疗中。本文使用MCNP4C软件计算美国医学物理学家协会(American association of physicists in medicine,AAPM)推荐的103Pd和125I的剂量学特征。由AAPM推荐的剂量学参量如剂...放射性光子源如103Pd和125I已被广泛用于前列腺和眼睛的植入治疗中。本文使用MCNP4C软件计算美国医学物理学家协会(American association of physicists in medicine,AAPM)推荐的103Pd和125I的剂量学特征。由AAPM推荐的剂量学参量如剂量率常数、径向剂量函数、各项异性函数通过Monte Carlo计算得到,在材料固体水WT1(solid water)中,125I的剂量率常数为0.99,103Pd的为0.682,而在材料Water中,125I剂量率为1.01。与前研究工作者Reners的计算结果相比125I的剂量率一致,而103Pd剂量率和各向异性函数结果相差较大,这些差异是使用不同Monte Carlo代码截面数据引起的。展开更多
Photoneutrons, emitted by means of photonuclear interactions when gas bremsstrahlung interacts with beamline components, can be another potential radiation source needed to be considered for shielding design and dose ...Photoneutrons, emitted by means of photonuclear interactions when gas bremsstrahlung interacts with beamline components, can be another potential radiation source needed to be considered for shielding design and dose assessment of beamline. In this paper, simulations and measurements of photoneutrons dose rate at beamline BL09 U are carried out when Shanghai Synchrotron Radiation Facility(SSRF) running at Top-up mode(3.5 GeV, 235 mA). A geometry model is constructed for the beamline BL09 U with considerations of the scattering process of the major optical components. The model is compiled into Monte Carlo simulation code FLUKA to calculate photoneutron dose distribution. Measurements of the photoneutrons dose rate were performed by using Environmental Neutron Monitor(ENM). Observation points were arranged uniformly along the inside and outside of the optical enclosure(OE) of BL09 U. The calculation results agree with experiments within the measurements uncertainties. It is verified that photoneutrons dose simulation is reliable. The simulation and measurement methods can be applied to evaluate the neutron dose level of other beamline stations, and provide references for the shielding design of the beamlines at SSRF in the near future.展开更多
This study investigated the characteristics of bremsstrahlung and induced neutrons from the elec- tron storage ring in the Shanghai Synchrotron Radiation Facility (SSRF).The EGSnrc and MCNP Monte Carlo code has been u...This study investigated the characteristics of bremsstrahlung and induced neutrons from the elec- tron storage ring in the Shanghai Synchrotron Radiation Facility (SSRF).The EGSnrc and MCNP Monte Carlo code has been used to perform the assess neutron and photon dose profiles for a variety of shield ma- terials ranging from 5 to 115cm thick.The Monte Carlo simulations show that single material such as lead, iron and polyethylene have been found to be ineffective biological shield materials,while the mixed materials serve as effective shields for shielding high energy neutron.Mixed materials such as lead or iron combined with polyethylene or with concrete are good materials combination for high energy neutron radiation shield.And high-Z materials such as lead or iron combine with low-Z material containing some hydrogen such polyethylene are effective for shielding high energy neutrons as well as bremsstrahlung.展开更多
The Shanghai Synchrotron Radiation Facility(SSRF)is a third-generation synchrotron radiation light source with 3.5GeV in energy,which is composed of the linear accelerator,the booster and the storage ring.The storage ...The Shanghai Synchrotron Radiation Facility(SSRF)is a third-generation synchrotron radiation light source with 3.5GeV in energy,which is composed of the linear accelerator,the booster and the storage ring.The storage ring provides 16 standard straight sections of 6.5m and 4 long straight sections of 12 meters. Gas Bremsstrahlung(GB)produced by the interaction of the stored beam with the residual gas molecules in straight section,which is so intense and has a very small angular that the GB spectra,the GB power and the GB power distribution should be known.The characters of GB are studied by means of Fluka Monte Carlo code.Our result shows agreement with those obtained by the experiential formulae.展开更多
文摘上海光源(Shanghai Synchrotron Radiation Facility,简称SSRF)是一个由国家投资建造的第三代同步辐射光源装置,由150MeV电子直线加速器、3.SGeV增强器和3.5GeV的储存环及同步辐射实验线站组成。SSRF在运行时,电子在增强器和储存环中产生大量同步辐射。同时,电子与真空管壁等发生相互作用产生轫致辐射和中子。SSRF固定辐射监测系统用于监测SSRF运行期间在主体建筑四周与环境中产生的辐射剂量水平。系统由探测器、智能模块、监控及管理计算机组成。该系统数据采集控制将基于EPICS(Experimental Physics and Industrial Control System)进行开发,搭建了收集多台前端智能模块数据,并进行处理、分析的软件系统。文中介绍该系统各组成部分的特点和工作原理,以及监控软件、分析软件所实现的具体功能。
文摘The energy response calibration of the commonly used high pressure ionization chamber is very difficult to obtain when the gamma-ray energy is more than 3 MeV. In order to get the calibration of the higher part of the high pressure ionization chamber, we use the Fluka Monte Carlo program to perform the energy response in both the spherical and the cylindrical high pressure ionization chamber which are full of argon gas. The results compared with prior study when the gamma-ray energy is less than 1.25 MeV. Our result of Monte Carlo calculation shows agreement with those obtained by measurement within the uncertainty of the respective methods. The calculation of this study is significant for the high pressure ionization chamber to measure the high energy gamma-ray.
文摘放射性光子源如103Pd和125I已被广泛用于前列腺和眼睛的植入治疗中。本文使用MCNP4C软件计算美国医学物理学家协会(American association of physicists in medicine,AAPM)推荐的103Pd和125I的剂量学特征。由AAPM推荐的剂量学参量如剂量率常数、径向剂量函数、各项异性函数通过Monte Carlo计算得到,在材料固体水WT1(solid water)中,125I的剂量率常数为0.99,103Pd的为0.682,而在材料Water中,125I剂量率为1.01。与前研究工作者Reners的计算结果相比125I的剂量率一致,而103Pd剂量率和各向异性函数结果相差较大,这些差异是使用不同Monte Carlo代码截面数据引起的。
文摘Photoneutrons, emitted by means of photonuclear interactions when gas bremsstrahlung interacts with beamline components, can be another potential radiation source needed to be considered for shielding design and dose assessment of beamline. In this paper, simulations and measurements of photoneutrons dose rate at beamline BL09 U are carried out when Shanghai Synchrotron Radiation Facility(SSRF) running at Top-up mode(3.5 GeV, 235 mA). A geometry model is constructed for the beamline BL09 U with considerations of the scattering process of the major optical components. The model is compiled into Monte Carlo simulation code FLUKA to calculate photoneutron dose distribution. Measurements of the photoneutrons dose rate were performed by using Environmental Neutron Monitor(ENM). Observation points were arranged uniformly along the inside and outside of the optical enclosure(OE) of BL09 U. The calculation results agree with experiments within the measurements uncertainties. It is verified that photoneutrons dose simulation is reliable. The simulation and measurement methods can be applied to evaluate the neutron dose level of other beamline stations, and provide references for the shielding design of the beamlines at SSRF in the near future.
文摘This study investigated the characteristics of bremsstrahlung and induced neutrons from the elec- tron storage ring in the Shanghai Synchrotron Radiation Facility (SSRF).The EGSnrc and MCNP Monte Carlo code has been used to perform the assess neutron and photon dose profiles for a variety of shield ma- terials ranging from 5 to 115cm thick.The Monte Carlo simulations show that single material such as lead, iron and polyethylene have been found to be ineffective biological shield materials,while the mixed materials serve as effective shields for shielding high energy neutron.Mixed materials such as lead or iron combined with polyethylene or with concrete are good materials combination for high energy neutron radiation shield.And high-Z materials such as lead or iron combine with low-Z material containing some hydrogen such polyethylene are effective for shielding high energy neutrons as well as bremsstrahlung.
文摘The Shanghai Synchrotron Radiation Facility(SSRF)is a third-generation synchrotron radiation light source with 3.5GeV in energy,which is composed of the linear accelerator,the booster and the storage ring.The storage ring provides 16 standard straight sections of 6.5m and 4 long straight sections of 12 meters. Gas Bremsstrahlung(GB)produced by the interaction of the stored beam with the residual gas molecules in straight section,which is so intense and has a very small angular that the GB spectra,the GB power and the GB power distribution should be known.The characters of GB are studied by means of Fluka Monte Carlo code.Our result shows agreement with those obtained by the experiential formulae.
