The transport process of 12C ions in water was studied with SRIM code and Geant4 toolkit. The SRIM results indicate that the transverse diffusion of 12C ion beam causes distortion of energy deposit along the beam dire...The transport process of 12C ions in water was studied with SRIM code and Geant4 toolkit. The SRIM results indicate that the transverse diffusion of 12C ion beam causes distortion of energy deposit along the beam direction. The distortion becomes more notable as the transverse diffusion increases. The simulation results of Geant4 indicate that the influence of secondary fragments on energy deposit distribution would be the main factor causing the distortion in higher energy range. In the region adjacent to the beam line where the contribution from 12C ions domi- nates, the contributions from secondary fragments are ignorable. The further from the beam axis the region locates, the larger the contributions from secondary fragments, until the contributions from secondary fragments are ignorable. The further from the beam axis the region locates, the larger the contributions from secondary fragments, until the contributions from secondary frag- ments exceed that of 12C. Among all the secondary fragments, the contributions of H, He and B ions are mostly notable. It is also found that some positron-emitting secondary fragments could be very useful for position emitting tomography （PET）.展开更多
An experiment for measuring the hyperon-related fission rate was carried out with the reaction 209^Bi（e, e＇K^＋）209^hPb at the Thomas Jefferson National Laboratory （Jlab）. In the experiment, the performance of th...An experiment for measuring the hyperon-related fission rate was carried out with the reaction 209^Bi（e, e＇K^＋）209^hPb at the Thomas Jefferson National Laboratory （Jlab）. In the experiment, the performance of the fission fragment detector （FFD） was dramaticlly crashed by the background particles in comparison with that during the test without beam. The scattering of the high intensity （500 nA） primary electrons was the dominant cause. Using the GEANT4 toolkit, this report simulates the experimental situation of the target chamber in which the FFD was located. The simulation results indicate that the background particles were dominantly （~ electrons, and protons and alpha particles were the important heavy background particles. The performance of the multi-wire proportional chambers （MWPCs） depends not only on the background-particle intensity but also the current density, which was also given by the simulation code. Furthermore, the measures to suppress the background particles were also investigated with the simulation code.展开更多
The gamma response function is required for energy calibration of EJ301 （5 cm in diameter and 20 cm in height） organic liquid scintillator detector by means of gamma sources. The GEANT4 and FLUKA Monte Carlo simulat...The gamma response function is required for energy calibration of EJ301 （5 cm in diameter and 20 cm in height） organic liquid scintillator detector by means of gamma sources. The GEANT4 and FLUKA Monte Carlo simulation packages were used to simulate the response function of the detector for standard 22Na, 60Co, 137Cs gamma sources. The simulated results showed a good agreement with experimental data by incorporating the energy resolution function to simulation codes. The energy resolution and the position of the maximum Compton electron energy were obtained by comparing measured light output distribution with simulated one. The energy resolution of the detector varied from 21.2% to 12.4% for electrons in the energy region from 0.341 MeV to 1.12 MeV. The accurate position of the maximum Compton electron energy was determined at the position 81% of maximum height of Compton edges distribution. In addition, the relation of the electron energy calibration and the effective neutron detection thresholds were described in detail. The present results indicated that both packages were suited for studying the gamma response function of EJ301 detector.展开更多
基金supported by the Fundamental Research Funds for the Central Universities of China(HEUCF101501)the Fundamental Research Funds of Harbin Engineering University of China(002150260713)
文摘The transport process of 12C ions in water was studied with SRIM code and Geant4 toolkit. The SRIM results indicate that the transverse diffusion of 12C ion beam causes distortion of energy deposit along the beam direction. The distortion becomes more notable as the transverse diffusion increases. The simulation results of Geant4 indicate that the influence of secondary fragments on energy deposit distribution would be the main factor causing the distortion in higher energy range. In the region adjacent to the beam line where the contribution from 12C ions domi- nates, the contributions from secondary fragments are ignorable. The further from the beam axis the region locates, the larger the contributions from secondary fragments, until the contributions from secondary fragments are ignorable. The further from the beam axis the region locates, the larger the contributions from secondary fragments, until the contributions from secondary frag- ments exceed that of 12C. Among all the secondary fragments, the contributions of H, He and B ions are mostly notable. It is also found that some positron-emitting secondary fragments could be very useful for position emitting tomography （PET）.
基金supported by the Fundamental Research Funds for the Central Universities of China (No.HEUCF101501)the Fundamental Research Funds of Harbin Engineering University of China (No.002150260713)
文摘An experiment for measuring the hyperon-related fission rate was carried out with the reaction 209^Bi（e, e＇K^＋）209^hPb at the Thomas Jefferson National Laboratory （Jlab）. In the experiment, the performance of the fission fragment detector （FFD） was dramaticlly crashed by the background particles in comparison with that during the test without beam. The scattering of the high intensity （500 nA） primary electrons was the dominant cause. Using the GEANT4 toolkit, this report simulates the experimental situation of the target chamber in which the FFD was located. The simulation results indicate that the background particles were dominantly （~ electrons, and protons and alpha particles were the important heavy background particles. The performance of the multi-wire proportional chambers （MWPCs） depends not only on the background-particle intensity but also the current density, which was also given by the simulation code. Furthermore, the measures to suppress the background particles were also investigated with the simulation code.
基金Supported by National Natural Science Foundation of China(11075189)100 Persons Project(0910020BR0,Y010110BR0)ADS Project 302(XDA03030200) of the Chinese Academy of Sciences
文摘The gamma response function is required for energy calibration of EJ301 （5 cm in diameter and 20 cm in height） organic liquid scintillator detector by means of gamma sources. The GEANT4 and FLUKA Monte Carlo simulation packages were used to simulate the response function of the detector for standard 22Na, 60Co, 137Cs gamma sources. The simulated results showed a good agreement with experimental data by incorporating the energy resolution function to simulation codes. The energy resolution and the position of the maximum Compton electron energy were obtained by comparing measured light output distribution with simulated one. The energy resolution of the detector varied from 21.2% to 12.4% for electrons in the energy region from 0.341 MeV to 1.12 MeV. The accurate position of the maximum Compton electron energy was determined at the position 81% of maximum height of Compton edges distribution. In addition, the relation of the electron energy calibration and the effective neutron detection thresholds were described in detail. The present results indicated that both packages were suited for studying the gamma response function of EJ301 detector.
