用于HPGe探测器效率标定的模拟气体刻度源的研制

准确校准测量系统的探测效率是HPGe探测器γ能谱法测量放射性气体活度的关键,放射性气体的半衰期一般较短且样品制备过程复杂,这些客观因素给效率校准工作带来很多不便。本工作提出了模拟气体刻度源的制备方案并进行了实验研究,所制备的模拟刻度源最小基质密度为0.043g/cm3,自吸收的影响小于0.5%。通过与效率参考值的比较表明,模拟气体刻度源的制备方案简单可行,所制备的模拟气体刻度源可代替气体标准源实现气体活度测量中HPGe探测器的效率校准以及探测效率的日常监督。     

4π内气体源的绝对测量

本文用长，短计数管补偿法消除端效应影响，并采用理想气体方程确定氚的质量，从而使氚水的放射性比活度的测量大大简化，精确计进一步改善。     

Ge（Li）探测器的体源峰效率刻度

本文介绍了用点源模拟法来刻度体源峰效率的方法和刻度结果,并与直接体源法相比较,误差约为5％。     

氙气样品的点源效率函数法HPGe谱仪测量

用HPGe γ谱仪,在5个高度上用241Am、137Cs、60Co混合点源测量Φ75 mm×25mm空样品不同剖面上不同位置的全能峰探测效率,用最小二乘拟合法确定点源峰效率函数中的的各参数值,用该点源效率函数对φ63.50 mm× 16.66 mm的氙气体样品进行数值积分计算,得氙气体的81.0、160.6、163.9...     

体源HPGeγ全能峰效率刻度的研究

本工作研究不同基体、不同几何体源的HPGeγ全能峰探测效率刻度方法。考虑了圆柱形体源的自吸收及级联符合相加效应对探测效率的影响,探索性提出了解决级联符合效应校正的新方法。     

微波功率源连锁保护装置研制

本文论述了-个微波功率源的连锁保护装置的设计.该系统核心是连锁保护控制电路,实现了对微波系统连锁保护信号和调制器连锁保护信号的实时监测和控制,且实现和PLC信号的传输.     

气体离心机流场模拟中源汇的耦合

用源汇模拟同位素分离气体离心机流场的供取料驱动和机械驱动是离心机流场计算中的方法之一。通过重新推导流体动力学方程组中的源汇表达式,得到不同的表达式。推导出的表达式反映了源汇之间的互相关联以及流场与源汇之间的互相影响,即源汇耦合,这些在以往的计算过程中均被忽略。由于考虑了源汇耦合,使得计算过程中部分源汇成为未知量,需在流场求解过程中予以确定。通过比较有无考虑源汇耦合计算得到的离心机流场可知,不考虑源汇耦合得到的结果虽能反映出分离室中流动基本规律,但数值上存在差异,得到的分离功也有较大差别。因此,计算过程中应考虑源汇的耦合。     

HPGe γ谱仪体源的效率与源高度的相关性分析

本文主要介绍得到HPGe γ谱仪对同一直径的圆柱形体源的效率ε与体源高度H的拟合回归方程的方法、结果及其验证。用包含^137 Cs等10种核素、14个能量(59．5～1836．0keV)的效率刻度用特征γ射线的掺标水溶液，分别制成11个相同活度、相同直径(φ=70mm)、不同高度(5～55mm)的标准源，在本实验室ORTEC公司的P型HPGe γ谱上进行效率刻度；由对某一能量Ei得出11种不同高度源的效率εi，按二次多项式拟合，得到相应于各个能量的一组回归方程：εi=c0i cliH c2iH^2，相关指数^2在0．9954～0．9993之间。应用所得ε～H回归方程，对φ=70mm，高度分别为21、33、42和57mm的环境土样，测量^40K、^226Ra和^232Th的比活度，对其平均值的最大偏差分别为3．1％、3．9％和4．3％；对φ=70mm，高度在9～57mm的一些标准物质的测量结果，与参考值符合较好；表明ε-H拟合回归方程在相应的条件下是适用的。     

HPGe环境放射性测量中样品盒形状选择与样品质量的关系

在环境样品放射性比活度测量中,放射性水平低,提高探测效率显得尤为重要。选择样品盒几何形状对提高探测效率具有明显的效果。论文利用MCNP程序模拟计算方法,得出了在HPGe探测器测量环境放射性样品中,不同样品质量下,探测效率最大时对应的马林杯样品和圆柱形样品盒几何形状,其结果可为环境样品测量时选取样品质量和样品盒形状提供依据。     

NaI(Tl)晶体对体源γ射线峰效率的确定

本文叙述了一个半径100mm 厚100mm 的 NaI(Tl)晶体对人体积源的γ射线全能峰效率的两种刻度方法,即点源实验模拟法和点源计算模拟法。放射源的自吸收介质选用水、土、大米、压缩南瓜和空气滤材五种。给出了两种刻度方法的结果,两者相对误差小于4%。     

Irradiation Test of Stainless Steel by High Power CO2 Laser

Electron beam, plasma arc and ion beam are often employed to simulate the high heat flux applied to the first wall or the divertor plate in a fusion reactor. In this study, an irradiation test with high heat flux was carried out under atmospheric condition by using high power CO₂ laser. The test material is SUS316 and the temperature change and the melting amount were measured. A thermal analysis code to take melting and evaporation behavior into account was developed. The laser absorption coefficient can be raised up to 95% before melting if special paint is coated on specimen surface. After melting, this coefficient is estimated to be 60% by thermal analysis. However, it was revealed that a precise modification of this model was indispensable. Although the effect of irradiation environment or heat source on material damage was also examined, there is no significant difference one another. In conclusion, it is found that CO₂ laser is quite suitable for use as a heat source to simulate a high heat flux.     

Characterization,test and interpretative simulations of one-dimensional Carbon Fiber Composite prototype for SPIDER experiment

For ITER operations, additional heating systems are required. One of these systems is the neutral beam injector (NBI). The SPIDER experiment, a small-scale NBI, is going to be built with the aim to optimize the beam source. For this reason it is provided with several diagnostics, among which the Short-Time Retractable Instrumented Kalorimeter Experiment (STRIKE). In this contribution, a characterization of the Carbon Fiber Composite (CFC) tiles, which are the main component of the diagnostic, is presented. Such analyses include tests with a power laser, exposure to particle beams and thermal stress tests. The results are discussed, which will drive the definition of the acceptance tests of the final supply of CFC tiles.     

不锈钢与铝合金材料之间密封用O形环性能分析

运用有限元分析软件,对不锈钢与铝合金法兰之间的O形环密封进行了分析。分析中考虑了材料的弹塑性变形。分析表明：对于5mm×0.5mm规格的预紧型不锈钢O形密封环,10%～20%的压缩量下的密封性能较佳,密封宽度0.2～0.3mm,接触压力80～120MPa,预紧比压100～130N/mm,这与O形环的设计压扁力120N/mm较为吻合。     

一种多阳极电离室的性能测试及初步应用

Bragg峰表征了带电粒子在介质中的能量沉积特性,通过分析带电粒子的分布和锐度可确定其在介质中的能量分布特征和单色性。本文介绍了一种能够快速探测带电粒子束在自由空气中形成的Bragg峰的多阳极电离室的设计原理、性能测试及初步应用。在⁹⁰Sr-⁹⁰Y源形成的β射线场中初步测出了电离室在自由空气中的电压-电流饱和特性、测量的重复性和稳定性,并测出²⁴¹Am源产生的α粒子在自由空气中的射程。初步实验结果表明：该电离室具有良好的饱和特性、测量稳定性和重复性,用它测出的α粒子在空气中的射程与SRIM程序模拟结果能够很好地符合。     

Catalytic Effect of Activated Carbon and Activated Carbon Fiber in Non-Equilibrium Plasma-Based Water Treatment

Catalysis and regeneration efficiency of granular activated carbon （GAC） and activated carbon fiber （ACF） were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange （MO） by the combined treatment can increase 22% （for GAC） and 24% （for ACF） respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H202 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.     

Radioactive Rare Gas Separation Performance of a Two-Unit Series-Type Separation Cell

Enhancement of the separation factor in a separation cell has been desired as one means of reducing the cascade scale required for a radioactive rare gas membrane separation. It is already known that the separation factor of the separation cell increases as cut increases. Hence, in a series-type separation cell which consists of two-unit cells, an appropriate selection of cuts for each unit cell can be expected to provide a marked improvement in separation factor under symmetric separation. This paper presents analytical and experimental results for separation characteristics of a series-type separation cell whose separation factors are far from unity. It was found that the series-type separation cell has a larger separation factor than other types of separation cells, such as recycle separation cell and conventional separation cell. The series-type separation cell requires less power consumption and membrane area than the recycle separation cell while it requires more than the conventional separation cell. As both the two-unit series-type separation cell and the conventional separation cell have individual merits and demerits, a comparison is also made between the cascade consisting of series-type separation cells and that of conventional separation cells. The cascade of series-type separation cells requires fewer stages and less power consumption but somewhat more membrane area than that of conventional separation cells. Based on results of this study, the scale of a cascade can be reduced by using series-type separation cell.     

大面积流气式电离室的研制及性能测试

核设施退役过程中,超铀核素放射性样品的无损测量一般通过γ能谱法实现,但由于超铀核素的γ射线发射几率一般较低,因此这种测量方法的探测限较高,不适用于溶解后低水平放射性样品的测量。本工作建立的大面积流气式电离室,通过探测α粒子电离空气的原理进行多孔样品的间接无损测量,方法探测限低,可以分析放射性活度低至百Bq级别的样品板。     

碳及碳团簇负离子注入硅橡胶细胞相容性研究

通过在GIC4117串列加速器前注入器加装注入靶架以及扫描系统,建立了低能负离子注入平台,实现具有"Charge-up free"优点的负离子以及团簇负离子的注入,从而进行了碳及碳团簇负离子注入硅橡胶细胞相容性研究。水接触角测量表明,随着注入剂量增大到3×1015 cm-2,材料表面的水接触角从108.7°减小到103.1°,表面亲水性得到改善。XPS测试表明,随着注入剂量的增加,样品中碳含量逐渐减小,而氧和氮含量逐渐增加。基于上述结果对负离子注入硅橡胶细胞相容性改善的机制进行了讨论,最后在样品上进行了细胞培养实验。结果表明,负离子注入法是一种简单、有效提升硅橡胶细胞相容性的方法。     

新型纤维增强环氧树脂基复合材料研制及其中子屏蔽性能研究

核技术应用产业的迅速发展,对中子辐射屏蔽材料的种类、服役环境、结构性能提出更多、更高要求。针对发展功能/结构一体化中子屏蔽材料需求,研制了一种新型玻璃纤维/B₄C/环氧树脂复合材料。力学测试与中子屏蔽实验发现,该复合材料中子屏蔽性能良好,5 cm厚样品屏蔽后中子透射率仅19.6%;材料具有较高强度与模量,性能优于铅硼聚乙烯。增大材料B₄C含量对提升材料中子屏蔽性能作用显著,但同时材料强度、模量有一定减小。综合考虑该材料的中子屏蔽性能、承受载荷以及耐高温特性,其在反应堆、加速器及中子源等核设施外围防护材料,尤其是乏燃料贮存格架材料用途上具有较大应用潜力。     

Ti35钛合金与低碳不锈钢在硝酸溶液中的电化学腐蚀对比研究

从电化学角度对Ti35合金(Ti-5%Ta)和超低碳不锈钢在硝酸溶液中的抗腐蚀性能进行了对比评价。对不同温度、不同浓度、不同添加离子等条件下的阳极极化曲线进行了测试。得到结论:在相同温度下,硝酸溶液浓度的变化导致了钛合金的腐蚀加剧。在相同浓度下,随着温度的升高,钛合金腐蚀越来越不明显。Cr6 离子浓度对钛合金腐蚀能力的影响不大。铀酰离子的作用较弱,加了铬和钌离子后表现出对阳极反应的明显抑制作用。通过表面微观形貌的观察,发现不锈钢对硝酸浓度的变化更为敏感,氧化性离子的综合作用对于不锈钢的耐蚀性影响很大。研究结果表明,Ti35合金具有比不锈钢优异得多的抗腐蚀性能,有希望取代000Cr25Ni20不锈钢而用于后处理设备。