通过蒙特卡罗生成库将库最小二乘分析法用于碳氧比仪器

传统碳氧比（C／O）仪器的探测效率相对较低、分辨率较差、信噪比较小。这主要是因为仪器自身的外径必须小，从而限制了探测器直径的尺寸。为了解决这一难题，作者建议采用蒙特卡罗一库最小二乘方法（MCLLS）（Montecarlo—Library Least—Squares），其中涉及用蒙特卡罗模拟生成完整的元素库，来使用整个采集谱。 为此，已开发并应用了专用的蒙特卡罗代码CEARCO。首先通过蒙特卡罗代码CEARCO生成探测器上的元素库谱事件，从而获得在碳氧比C／O仪器内产生伽马射线的所有元素的元素库谱。然后再利用这些库谱和未知的混合碳氧比谱计算出碳、氧的量和用库最小二乘方法（LLS）表示的其它元素的数量。据估计，与只使用峰强度及可用数据的窗口法所得出的结果相比，这个方法所得结果的不确定性要小2～3倍。

A Monte Carlo Simulation of Radiation Damage of SiC and Nb Using JA-IPU Code

MC （Monte Carlo） simulation code, JA-IPU is used to study radiation damage of SiC irradiated to spallation neutron and AmBe neutron spectra. The code is based on the major physical processes of radiation damage on incorporation of atomic collision cascade and limited to 10 MeV neutron energy. A phenomenological relation for radiation swelling is also derived. Based on the calculation of swelling, DPA （displacement per atom）, defect production efficiency and effective threshold energy, Efff from the data of MC simulation, SiC is inferred to be a highly radiation resistant material when compared with Nb and Ni metals which are used in composition of several reactor steels. Experimental results of hill-hock density measured using AFM （atomic force microscopy）, also confirm radiation resistant behavior of SiC.

Nuclear Properties of Carbon Nanotubes for Fast Neutron Detection

Fast neutron detection is a subject of great relevance in modem nuclear science and engineering, in particular, with the recent advances in nuclear fusion research, detection of fast neutron became a key issue. Nuclear properties of carbon are of special interest due to its relatively high capture cross section for fast neutrons. Devices made of silicon carbide and diamond are based on these properties, and so are being developed to be used with the proper wiring. In addition, in recent years carbon nano-tubes unveiled their electrical and mechamical properties, which can be exploited for neutron detection. In this work, we use MCNP5 Monte Carlo code to analyze the carbon nuclear properties and discuss the way nano-tubes can be used for fast neutron detection.

^103pd放射性支架的三维剂量率分布

目的研究^103Pd放射性支架的三维剂量率分布。方法用模拟实验、理论计算和蒙特卡罗代码（MCNP4b）3种方法估算3mm×13mm支架的表面剂量、表面轴向剂量和径向分布，支架活度为2．9×10^6Bq。用MCNP4b计算支架的三维剂量率分布。结果模拟实验和MCNP4b计算的支架表面剂量分别为0．109、0．106Gy，两者差异〈3％。理论计算和MCNP4b计算的轴向剂量一致。3种方法计算的径向剂量也一致。用MCNP4b估算了^103Pd放射性支架三维剂量率分布。结论3种方法估算的^103Pd放射性支架的剂量都比较准确。用MCNP4b计算的支架三维剂量率分布数据可为动物实验和临床应用提供剂量学参考。