机构地区：[1]State Key Laboratory of Nuclear Physics and Technology,School of Physics,Peking University,Beijing 100871,China [2]Institute of High Energy Physics,Chinese Academy of Sciences(CAS),Beijing 100049,China [3]Spallation Neutron Source Science Center,Dongguan 523803,China [4]State Key Laboratory of Particle Detection and Electronics [5]Department of Modem Physics,University of Science and Technology of China,Hefei 230026,China [6]Key Laboratory of Nuclear Data,China Institute of Atomic Energy,Beijing 102413,China [7]Institute of Nuclear Physics and Chemistry,China Academy of Engineering Physics,Mianyang 621900,China [8]Northwest Institute of Nuclear Technology,Xi'an 710024,China [9]University of Chinese Academy of Sciences,Beijing 100049,China [10]Department of Engineering and Applied Physics,University of Science and Technology of China,Hefei 230026,China [11]School of Physics,Beihang University,Beijing 100083,China
出 处：《Chinese Physics C》2019年第12期47-74,共28页中国物理C（英文版）
基 金：Supported by financially the National Key R&D Program of China(2016YFA0401604);the National Natural Science Foundation of China(11775006)
摘 要：Differential and angle-integrated cross sections for the 10B(n,α)^7 Li,10B(n,α0)^7 Li and 10B(n,α1)^7 Li^*reactions have been measured at CSNS Back-n white neutron source.Two enriched(90%)10B samples 5.0 cm in diameter and^85.0μg/cm^2 in thickness each with an aluminum backing were prepared,and back-to-back mounted at the sample holder.The charged particles were detected using the silicon-detector array of the Light-charged Particle Detector Array(LPDA)system.The neutron energy En was determined by TOF(time-of-flight)method,and the valid a events were extracted from the En-Amplitude two-dimensional spectrum.With 15 silicon detectors,the differential cross sections of a-particles were measured from 19.2°to 160.8°.Fitted with the Legendre polynomial series,the(n,a)cross sections were obtained through integration.The absolute cross sections were normalized using the standard cross sections of the 10B(n,α)^7 Li reaction in the 0.3-0.5 MeV neutron energy region.The measurement neutron energy range for the 10B(n,α)^7 Li reaction is 1.0 eV≤En<2.5 Me V(67 energy points),and that for the 10B(n,α0)^7 Li and10B(n,α1)^7 Li^*reactions is 1.0 eV≤En<1.0 MeV(59 energy points).The present results have been analyzed by the resonance reaction mechanism and the level structure of the 11B compound system,and compared with existing measurements and evaluations.Differential and angle-integrated cross sections for the 10B（n,α）7 Li,10B（n,α0） 7 Li and 10B（n,α1） 7 Li*reactions have been measured at CSNS Back-n white neutron source.Two enriched（90%） 10B samples 5.0 cm in diameter and～85.0 μg/cm2 in thickness each with an aluminum backing were prepared,and back-to-back mounted at the sample holder.The charged particles were detected using the silicon-detector array of the Light-charged Particle Detector Array（LPDA） system.The neutron energy En was determined by TOF（time-of-flight） method,and the valid a events were extracted from the En-Amplitude two-dimensional spectrum.With 15 silicon detectors,the differential cross sections of a-particles were measured from 19.2°to 160.8°.Fitted with the Legendre polynomial series,the（n,a） cross sections were obtained through integration.The absolute cross sections were normalized using the standard cross sections of the 10B（n,α） 7 Li reaction in the 0.3-0.5 MeV neutron energy region.The measurement neutron energy range for the 10B（n,α） 7 Li reaction is 1.0 eV≤En <2.5 Me V（67 energy points）,and that for the 10B（n,α0） 7 Li and10B（n,α1） 7 Li*reactions is 1.0 eV≤En<1.0 MeV（59 energy points）.The present results have been analyzed by the resonance reaction mechanism and the level structure of the 11B compound system,and compared with existing measurements and evaluations.
关 键 词：10B(n α)^7Li REACTION cross SECTIONS LPDA CSNS Back-n white NEUTRON source
分 类 号：O57[理学—粒子物理与原子核物理]
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