基于上海激光电子γ源的天体核合成关键反应12C(α,γ)16O的反应率研究

正在研制的上海激光电子γ源是MeV量级的高品质γ光束线站，基于该装置可以开展一系列核天体物理实验, 从而更准确的确定各天体核合成反应的反应率. 本文研究了天体核合成中的关键反应¹²C(α,γ)¹⁶O的反应率. 根据多组实验和理论截面数据分别计算了反应率, 并给出了这些反应率计算结果的平均值和统计误差. 根据该结果拟合了理论反应率的解析形式, 确定了新的参数. 进而给出俘获反应¹²C(α,γ)¹⁶O在He燃烧环境下的反应率和误差, 并讨论了电子屏蔽效应对天体反应率的修正.     

上海激光电子γ源

激光具有高强度、 高极化度等优异的性能。 用激光束轰击高能电子束就可以产生高强度、 高极化度的γ射线束。 上海激光电子γ源就是上海同步辐射装置上的这样一条束线站。 预计可以获得能量范围为1—22 MeV的准单色、 高强度（109—1011 s-1）和高极化度（线极化或圆极化）的γ射线束。 介绍了这条束线站目前的进展情况。 Shanghai Laser Electron Gamma Source (SLEGS) is a high intensity,short pulse and compact γ ray source which is based on inverse Compton scattering via interaction between pulsed high power laser beams and picosecond relativistic electron bunches. One of the attractive features of the laser Compton scattering is the easy control of polarization of the produced high energy photons that duplicates polarization of the applied laser beam. The γ ray with energy up to 22 MeV and intensity of 109—1011s 1 are expected to be produced by Compton backscattering of CO2 laser photons on the 3.5 GeV electrons bunches in the Shanghai Synchrotron Radiation Facility (SSRF). In this communication, we report same simulation results and the progressing status of SLEGS.     

Low Energy Ion Channelling in Single-Wall Nanotubes

Monte Carlo simulation is used to study the low energy He ion channelling in a （17, 0） single-wall nanotube and its rope. The simulation shows that the channelling critical angle ψc = 48E^-1/2 （E is incident energy） for a 1.31-nm-diameter initial beam into the nanotube, while ψc = 45E^-1/2 for the 1.31-nm-diameter initial beam into its rope.     

关于SOP数的计算和估计

本文对A M Odlyzko等人提出的SOP数a(n)证明了: (ⅰ) a(2)=1/2; (ⅱ) ■C>0,■Cn~(1/2)≤a(n)≤0.5+O(n~(-1))≤0.75。     

Phenomenological Study of 3He Photodisintegration up to 150MeV

A parametrization of ^3He（7,p）2H cross section data at laboratory photon energies between 9 and 150MeV iscarried out with a simple phenomenological function. The differential cross section data are normalized to the total cross-section values which are consistent with the measurement from monochromatic photon beams. The obtained results give a good representation of the experimental points.