The 13C（7Li, 6He）laN reaction is measured at E（TLi） = 34 MeV with the Q3D mag- netic spectrometer of HI-13 tandem accelerator. Angular distributions at forward angles for proton transfer to the ground and the firs...The 13C（7Li, 6He）laN reaction is measured at E（TLi） = 34 MeV with the Q3D mag- netic spectrometer of HI-13 tandem accelerator. Angular distributions at forward angles for proton transfer to the ground and the first excited states in 14N are obtained. In addition, angular distri- bution for 7Li ＋ 13C elastic scattering is also measured. The optical potential parameters for the entrance and exit channels of the transfer reactions are derived by fitting the 7Li ＋ 13C and 6Li ＋ 14N elastic scattering experimental data, and their angular distributions are well reproduced by the distorted wave Born approximation calculations. A phase shift of about 2° between the calculations and the experiment data has been found in the earlier （TLi, 6He） study, whereas no such phase shift is observed in the present work.展开更多
The 13^C（a, n）160 reaction is believed to be the main neutron source reaction for the s-process in asymptotic giant branch （AGB） stars. The astrophysical S-factors of this reaction have been determined based on an...The 13^C（a, n）160 reaction is believed to be the main neutron source reaction for the s-process in asymptotic giant branch （AGB） stars. The astrophysical S-factors of this reaction have been determined based on an evaluation of the a spectroscopic factor of the 1/2＋ subthreshold state in 17^O （Ex = 6.356 MeV） by using the 13^C（11^B, 7^Li）17^O a transfer reaction. Our result confirms that the 1/2＋ subthreshold resonance is dominant for the 13^C（a, n）16^O reaction at low energies of astrophysical interest.展开更多
This paper presents the results of a study that compares CTOM, a microscopic optical model potential(OMP), which is an optical model co-created by the China Nuclear Data Center & Tuebingen University, to CH89, whi...This paper presents the results of a study that compares CTOM, a microscopic optical model potential(OMP), which is an optical model co-created by the China Nuclear Data Center & Tuebingen University, to CH89, which is a typical phenomenological OMP.The respective OMPs were tested by applying them to the modelling of nucleon elastic scattering and(d,p) transfer reactions involving14C,36S, and58Ni targets at both low and relatively high energies. The results demonstrated that although both potentials successfully accounted for the angular distributions of both the elastic scattering and transfer cross sections, the absolute values of the transfer cross sections calculated using CTOM were approximately 25% larger than those calculated using CH89. This increased transfer cross sections allowed CTOM to produce single particle strength reduction factors for the three reactions that were consistent with those extracted from(e,e′p) reactions as well as with more recent(p,2p) and(p,pn) reactions. Notch tests suggested that nucleon elastic scattering and transfer reactions are sensitive to different regions of the OMP;accordingly,phenomenological OMPs, which are constrained only by elastic scattering cross sections, may not be sufficient for nucleon transfer reactions. Therefore, we suggest that microscopic OMPs, which reflect more theoretical considerations, should be preferred over phenomenological ones in calculations of direct nuclear reactions.展开更多
基金supported by National Natural Science Foundation of China (Nos. 11021504, 10975193, 10735100, 10720101076)the National Basic Research Program of China (No. 2007CB815003)
文摘The 13C（7Li, 6He）laN reaction is measured at E（TLi） = 34 MeV with the Q3D mag- netic spectrometer of HI-13 tandem accelerator. Angular distributions at forward angles for proton transfer to the ground and the first excited states in 14N are obtained. In addition, angular distri- bution for 7Li ＋ 13C elastic scattering is also measured. The optical potential parameters for the entrance and exit channels of the transfer reactions are derived by fitting the 7Li ＋ 13C and 6Li ＋ 14N elastic scattering experimental data, and their angular distributions are well reproduced by the distorted wave Born approximation calculations. A phase shift of about 2° between the calculations and the experiment data has been found in the earlier （TLi, 6He） study, whereas no such phase shift is observed in the present work.
基金supported by National Basic Research Program of China (No.2007CB815003)National Natural Science Foundation of China(Nos.10705053,11021504,10720101076,10735100 and 10975193)
文摘The 13^C（a, n）160 reaction is believed to be the main neutron source reaction for the s-process in asymptotic giant branch （AGB） stars. The astrophysical S-factors of this reaction have been determined based on an evaluation of the a spectroscopic factor of the 1/2＋ subthreshold state in 17^O （Ex = 6.356 MeV） by using the 13^C（11^B, 7^Li）17^O a transfer reaction. Our result confirms that the 1/2＋ subthreshold resonance is dominant for the 13^C（a, n）16^O reaction at low energies of astrophysical interest.
基金supported by the National Natural Science Foundation of China(Grant Nos.11775013,U1432247,11775316,U1630143,and 11465005)the National Key Research and Development Program(Grant No.2016YFA0400502)Science Challenge Project(Grant No.TZ2018001)
文摘This paper presents the results of a study that compares CTOM, a microscopic optical model potential(OMP), which is an optical model co-created by the China Nuclear Data Center & Tuebingen University, to CH89, which is a typical phenomenological OMP.The respective OMPs were tested by applying them to the modelling of nucleon elastic scattering and(d,p) transfer reactions involving14C,36S, and58Ni targets at both low and relatively high energies. The results demonstrated that although both potentials successfully accounted for the angular distributions of both the elastic scattering and transfer cross sections, the absolute values of the transfer cross sections calculated using CTOM were approximately 25% larger than those calculated using CH89. This increased transfer cross sections allowed CTOM to produce single particle strength reduction factors for the three reactions that were consistent with those extracted from(e,e′p) reactions as well as with more recent(p,2p) and(p,pn) reactions. Notch tests suggested that nucleon elastic scattering and transfer reactions are sensitive to different regions of the OMP;accordingly,phenomenological OMPs, which are constrained only by elastic scattering cross sections, may not be sufficient for nucleon transfer reactions. Therefore, we suggest that microscopic OMPs, which reflect more theoretical considerations, should be preferred over phenomenological ones in calculations of direct nuclear reactions.
