A method of estimating and subtracting the hydrogen background in the natural carbon target used in the ~(12)C + ~(12)C experiment

The experimental data of 100 A MeV12C +12C elastic scattering are checked by using two-body kinematic calculation and12 C + p elastic scattering. It is shown that the measured data are true and reliable. In the paper,the transformation between the excited energy spectra of the12 C +12C system and the ground state energy spectra of the12 C + p system is introduced. The method of subtraction of the hydrogen background in the natural carbon target used in the experiment is elaborately described and the results are discussed. It is indicated that this method of subtraction of hydrogen background is reasonable and can be used in the data analysis. Based on the elastic scattering cross section of the previous experiment of12C+p at 95.3A MeV, the hydrogen content entered into the reaction is analyzed. The final hydrogen content in the natural carbon target is(2.73 ± 0.12)%.     

多像素光子计数器的能量分辨性能测试

随着新型光电转换器件技术的快速发展,多像素光子计数器(Multi Pixel Photon Counter,MPPC)逐渐被应用到核辐射探测等相关领域。本文将MPPC分别与碘化铯(Cs I)、碘化钠(Na I)以及锗酸铋(Bi4Ge3O12,BGO)闪烁晶体进行光学耦合,测量137Cs、60Co两种γ射线放射源的三个特征峰的能谱,测试结果与光电倍增管(Hamamatsu H7195)和闪烁晶体耦合所测得的结果进行了对比。此外,用自制的前置放大器与波形数字采样器(CAEN DT5730)对MPPC的输出信号进行了采集测试。结果表明:MPPC相比于光电倍增管,其能量分辨率稍差,但是具有相当的能量线性。