30mev以下中子誘發(fā)39;12c、39;16o輕核反應的kerma系數研究

1、廣西師范大學碩士學位論文30MeV以下中子誘發(fā)C、O輕核反應的kerma系數研究姓名：渠文靜申請學位級別：碩士專業(yè)：理論物理指導教師：柳繼鋒;孫小軍20080401廣西師范大學碩士學位論文 iiThe study of neutron kerma coefficients for n+12C(16O) nuclear reaction below 30MeV Abstract Kerma (kinetic energy release

2、d in materials) coefficients are important in many fields, such as determining the radiation scathing and shielding in nucleus engineering, predicting and analyzing the thermomechanical performance, and determining the d

3、ose delivery in therapy beams. And the 12C and 16O kerma coefficients are the most important and useful. According the new model of neutron induced light nucleus reactions, this thesis determine a new kerma coefficients

4、formula which can calculate kerma coefficients for all kinds of emitted particles in diversified channels. 0 ( ) tot j ijk ijk n j ijk k k N E ε σ = = ∑ ∑where tot kis the total kerma coefficient expressed in fGym2. j

5、k is the kerma coefficient of the charged particle or recoil nuclear of type j in nucleus reactions. In the laboratory system, ) ( n ijk E εand ) ( n ijk E σ are the average energy (expressed in MeV) and production cr

6、oss section (expressed in barns), which are all the function of the incident neutron energy n E . Here, i denotes the type of reaction channels and k signs the excitation energy level of residual nucleus which can emit

7、 the secondary particle, or proceed via two-body separation, or carry out gamma decay. It is the first time to present such particular and comprehensive information for kerma coefficients. On the basis of this new model,

8、 LUNF code is modified to calculate part and total kerma coefficient for n+12C and n+16O reactions from the threshold energy to 30 MeV. We have calculated the kerma coefficients of alpha, protons, deuterons, tritons, He3

9、, Li6, elastic recoil and total at n+12C and n+16O reactions. The results agree fairly well with the experimental data and evaluations. We analyze the channels carefully and gain the average energies ijk ε of all kinds

10、of the emitted particles in the laboratory frame. At the same time, we obtained new optical potential parameters for 12C and 16O respectively. However, the new model of neutron induced light nucleus reactions can obtain

11、 the cross section of total and elastic scattering in a smooth curve only, but their experimental and evaluated cross sections have many structures at the low neutron energy region. So, the elastic cross section and thei

12、r 1st Legendre coefficient 1 1 m f derived from CENDL-3.1 are used when we calculate the kerma coefficients of 12C, and the elastic cross section and their 1st Legendre coefficient 1 1 m f derived from ENDF/B-VII6.3 ar