快中子辐照对枯草芽孢杆菌的灭菌效果研究

利用快中子脉冲堆(Chinese Fast Burst ReactorⅡ,CFBR-Ⅱ)产生的快中子,采用枯草芽孢杆菌黑色变种为材料,考查了中子辐射灭菌效果及剂量、剂量率、辐照温度、照射状态等辐射灭菌影响因素.结果表明,在剂量率为7.4 Gy/min时的D10值为384.6Gy,中子剂量与存活芽孢对数满足y=-0.0026x 10.462的函数关系;在剂量为800Gy时,剂量率与存活芽孢对数满足y=7.7414X-0.0834的函数关系;升高温度有利于中子辐射灭菌;中子辐照不同状态芽孢,其存活率为:菌片＞粉末＞液体.     

铝外壳Si（Au）面垒探测器受快中子辐照后性能恢复的研究

本文研究了探测器经注量＜10^15n/cm^2的快中子辐照后，在重新加偏压过程中它们的反向电流猛增而使性能变坏的原因，然后采用慢加偏压的方式恢复了探测器的性能，延长了使用寿命。     

快中子照相的实验研究

快中子照相是一种优良的无损检测技术,它有着X射线、热中子照相等所不具有的独特优势。本文介绍了作者分别采用^241Am-Be同位素中子源和中子发生器进行的快中子照相研究,并利用自制的Gd2O2S：Tb快中子转换发光屏进行探测,成功实现照相。     

Effects of fast neutron and gamma irradiation on electrical conductivity of some borate glasses

Electrical conductivity of samples of Li₂O-B₂O₃ binary glass system containing Al₂O₃, PbO, Fe₂O₃, TiO₂ or V₂O₅ was measured at temperatures ranging between 30 and 200 °C before and after irradiation with fast neutrons or γ-rays. Base and Al₂O₃-containing glasses showed an initial rise in conductivity with the increasing temperature, followed by a steep drop, then a more gradual increase. Glass samples containing lead or one of the transition metal oxides showed a linear pattern of electrical conductivity in response to heating. In these glasses activation energy varied depending on the coordination number of the transition metal ion involved. These changes in electrical conductivity in response to temperature are ascribed to changes in the internal structure of the lithium borate glass, which is also affected by the presence of aluminum, lead or transition metals. The effects of exposing the studied glasses to irradiation were attributed to irradiation-induced changes in the configuration of the glass network, including the formation of matrix defects.     

Experiments on mine—detection with fast neutron activation

Fast neutron activation of nitrogen and oxygen contained in the explosives used for simulated mine samples has been preliminarily carried out in our laboratory.By spectroscopic analysis of characteristic γ-rays emitted from activated nitrogen and oxygen,mine can be idenfitied almost instantly.This technique integrated with robotics would be a method for mine scavenging.     

快脉冲中子场响应中的电磁干扰研究

在利用闪烁中子探测器进行DPF中子参数测量时，认真分析了测量过程中出现的电磁干扰现象，并采用合理的技术手段给予消除，得到了满意的测量结果。     

Remarks on the theory of fast neutron sputtering

Theoretical estimates of neutron sputtering yields are in serious disagreement with experiment, unlike the situation with ion sputtering. Possible reasons for the discrepancy are sought without success. It is shown that chunk ejection by neutrons is not due to either single neutron events or to the dynamic interference of cascades. The need for more complete experimental data to guide development of the theory is emphasized.     

Irradiation performance of polytetrafluoroethylene (Teflon) in a mixed fast neutron and gamma radiation field

Samples of polytetrafluoroethylene have been irradiated with a mixed field of fast neutrons and gamma rays using the MIT Research Reactor. Dose levels from ∼0.3 to ∼50×10⁶ Gy for gamma and from ∼0.13 to 80×10⁴ Gy for fast neutrons were used. Weight loss, fluorine loss, and swelling were measured quantitatively. Subjective mechanical property tests were also performed to assess embrittlement. Aside from high levels of embrittlement, no large changes, ?1.5%, were observed in the properties which were assayed even at the highest doses.     

多气隙电阻板室快中子探测器性能模拟

介绍了一种具有优良时间分辨率的新型快中子探测器,用蒙特卡罗方法模拟了该探测器的能量响应和产生质子的转换效率,分析了其n/γ分辨能力.该探测器结合飞行时间法可以准确地测量快中子能谱.     

Isochronal recovery of fast neutron irradiated metals

The isochronal recovery of Al, Ni, Cu, Ag. Au, Pt, Fe, Mo and Co, irradiated at 4.5K with fast neutrons has been studied resistometrically. For the face-centered cubic elements, Al, Ni, Cu, Ag, and Au, the magnitude of stage I recovery is inversely proportional to the atomic mass of these elements, which is in excellent agreement with recent calculations on the spatial distribution of lattice defects in fast neutron irradiated metals. The total irradiation-induced resistivity and hardness of neutron spectra have more of an influence on the details of the recovery stages than does the initial residual resistivity and the initial resistivity ratio. Stage II recovery, at least in Cu, can be explained best by the rearrangement and/or annihilation of defects that are released from the stress fields of the vacancy clusters that exist in fast neutron irradiated metals.     

多探测器快中子飞行时间谱仪

描述了一台串列加速器HI-13上的多探测器快中子飞行时间谱仪,并与国际上同类谱仪进行了比较。本谱仪主要用于能量大于8 MeV的快中子散射实验、次级中子双微分截面及带电粒子引起的出射中子能谱的测量。简要介绍了谱仪各主要部分(包括零信号拾取筒、氘气体靶、探测器、电子学等)的结构和特性及其在快中子实验中的应用。     

PIN型快中子剂量探测器的结构研究

介绍了不同结构比例的PIN宽基硅二极管快中子剂量探测器对^236mPu-Be中子源的剂量响应测试结果。通过对实验结果进行分析,建立了探测器的等效电路模型,得出了探测器的剂量响应与结构比例参数(d／A)近似成线性关系的结论。