We study in the framework of the Langevin model the influence of initial excitation energy(E*) of Hg compound nuclei(CNs) on the sensitivity of the excitation energy at scission(Esc*) to the nuclear friction strength(...We study in the framework of the Langevin model the influence of initial excitation energy(E*) of Hg compound nuclei(CNs) on the sensitivity of the excitation energy at scission(Esc*) to the nuclear friction strength(β).It is shown that the sensitivity is enhanced substantially with increasing E*.Moreover,we find that the significant sensitivity of Esc* to β at high E*is little affected by a marked difference in the neutron-to-proton ratio of a CN and in its size and fissility.Our findings suggest that,on the experimental side,a measurement of Esc* in energetic proton-induced spallation reactions can provide not only a sensitive but also a robust probe of nuclear dissipation in fission of highly excited nuclei.Further development of a suitable approach to spallation reaction is discussed.展开更多
A Neutron Time-of-Flight(NTOF) spectrometer, based at the Heavy Ion Research Facility in Lanzhou(HIRFL) was developed for studies of neutron production of proton induced spallation reactions related to the ADS project...A Neutron Time-of-Flight(NTOF) spectrometer, based at the Heavy Ion Research Facility in Lanzhou(HIRFL) was developed for studies of neutron production of proton induced spallation reactions related to the ADS project. After the presentation of comparisons between calculated spallation neutron production doubledifferential cross sections and the available experimental data, a detailed description of the NTOF spectrometer is given. Test beam results show that the spectrometer works well and data analysis procedures are established.The comparisons of the test beam neutron spectra with those of GEANT4 simulations are presented.展开更多
基金Supported by National Natural Science Foundation of China(NSFC) Projects (No.11075034)
文摘We study in the framework of the Langevin model the influence of initial excitation energy(E*) of Hg compound nuclei(CNs) on the sensitivity of the excitation energy at scission(Esc*) to the nuclear friction strength(β).It is shown that the sensitivity is enhanced substantially with increasing E*.Moreover,we find that the significant sensitivity of Esc* to β at high E*is little affected by a marked difference in the neutron-to-proton ratio of a CN and in its size and fissility.Our findings suggest that,on the experimental side,a measurement of Esc* in energetic proton-induced spallation reactions can provide not only a sensitive but also a robust probe of nuclear dissipation in fission of highly excited nuclei.Further development of a suitable approach to spallation reaction is discussed.
基金Supported by National Natural Science Foundation of China(No.11075189)100 Persons Project(Nos.0910020BR0 and Y010110BR0)ADS Project 302 of the Chinese Academy of Sciences(No.XDA03030200)
文摘A Neutron Time-of-Flight(NTOF) spectrometer, based at the Heavy Ion Research Facility in Lanzhou(HIRFL) was developed for studies of neutron production of proton induced spallation reactions related to the ADS project. After the presentation of comparisons between calculated spallation neutron production doubledifferential cross sections and the available experimental data, a detailed description of the NTOF spectrometer is given. Test beam results show that the spectrometer works well and data analysis procedures are established.The comparisons of the test beam neutron spectra with those of GEANT4 simulations are presented.
