The detection efficiency of the fission chamber(FC) is very important for studying the neutron flux measurement(NFM) system in ITER. In this article, we mainly focus our attention on the influence of the moderator. Wi...The detection efficiency of the fission chamber(FC) is very important for studying the neutron flux measurement(NFM) system in ITER. In this article, we mainly focus our attention on the influence of the moderator. With the Monte Carlo particle transport simulation tool named Geant4, we make a simulation of FC detection efficiency with different levels of thickness of a beryllium moderator.Two manufactured FCs for ITER-NFM systems are then used to test the parameters and performance. The test results agree well with our simulation.展开更多
We report a reconstruction method for fast-fission events in 25 MeV/u^(86)Kr +^(208)Pb reactions at the Compact Spectrometer for Heavy Ion Experiment(CSHINE). The fission fragments(FFs) are measured using three large-...We report a reconstruction method for fast-fission events in 25 MeV/u^(86)Kr +^(208)Pb reactions at the Compact Spectrometer for Heavy Ion Experiment(CSHINE). The fission fragments(FFs) are measured using three large-area parallel-plate avalanche counters, which can deliver the position and arrival timing information of the fragments. The start timing information is provided by the radio frequency of the cyclotron. Fission events were reconstructed using the velocities of the two FFs. The broadening of both the velocity distribution and azimuthal difference of the FFs decreases with the folding angle, in accordance with the picture that fast fission occurs. The anisotropic angular distribution of the fission axis also consistently reveals the dynamic features of fission events.展开更多
Erperimental method to measure the prompt neutron spectra of 238U fissioninduced by fast neutrons has been developed at HI-13 Tandem Van de Grab Accelerator Laboratory of CIAE. These techniques employ a multi-segment ...Erperimental method to measure the prompt neutron spectra of 238U fissioninduced by fast neutrons has been developed at HI-13 Tandem Van de Grab Accelerator Laboratory of CIAE. These techniques employ a multi-segment fission chamberand tab liquid scintillator neutron detectors. TOF (time of flight) techniques are usedfor prilnny neutrons to select the fission evellts induced by monoenergetic neutronfrom 'H(d, n) reactions instead of breakup neutrons from 'H(d, up) reactions. Thefission neutron TOF spectra are measured in coincidence with the fission fragmellts todistinguish fission neutrons from other secondals neutrons. The method perests measurements to a forly good accuracy under large neutron and gamma ray baCkgroulld.The tecboques are described and experimelltal spectra are presented.展开更多
基金supported by the National Natural Science Foundation of China(Nos.10976028 and 11375195)the National Magnetic Confinement Fusion Energy Development Research(No.2013GB104003)
文摘The detection efficiency of the fission chamber(FC) is very important for studying the neutron flux measurement(NFM) system in ITER. In this article, we mainly focus our attention on the influence of the moderator. With the Monte Carlo particle transport simulation tool named Geant4, we make a simulation of FC detection efficiency with different levels of thickness of a beryllium moderator.Two manufactured FCs for ITER-NFM systems are then used to test the parameters and performance. The test results agree well with our simulation.
基金supported by the National Natural Science Foundation of China(Nos.11875174,11961131010,and 11961141004)the Polish National Science Center(No.2018/30/Q/ST2/00185)。
文摘We report a reconstruction method for fast-fission events in 25 MeV/u^(86)Kr +^(208)Pb reactions at the Compact Spectrometer for Heavy Ion Experiment(CSHINE). The fission fragments(FFs) are measured using three large-area parallel-plate avalanche counters, which can deliver the position and arrival timing information of the fragments. The start timing information is provided by the radio frequency of the cyclotron. Fission events were reconstructed using the velocities of the two FFs. The broadening of both the velocity distribution and azimuthal difference of the FFs decreases with the folding angle, in accordance with the picture that fast fission occurs. The anisotropic angular distribution of the fission axis also consistently reveals the dynamic features of fission events.
文摘Erperimental method to measure the prompt neutron spectra of 238U fissioninduced by fast neutrons has been developed at HI-13 Tandem Van de Grab Accelerator Laboratory of CIAE. These techniques employ a multi-segment fission chamberand tab liquid scintillator neutron detectors. TOF (time of flight) techniques are usedfor prilnny neutrons to select the fission evellts induced by monoenergetic neutronfrom 'H(d, n) reactions instead of breakup neutrons from 'H(d, up) reactions. Thefission neutron TOF spectra are measured in coincidence with the fission fragmellts todistinguish fission neutrons from other secondals neutrons. The method perests measurements to a forly good accuracy under large neutron and gamma ray baCkgroulld.The tecboques are described and experimelltal spectra are presented.
