新型硅吸收剂量量热计的应用

叙述了一种新型硅吸收剂量量热计的结构、电加热校准情况及其测量原理,给出了用该量热计标定中国科学院新疆物理研究所＾６０Ｃｏγ辐照室中吸收剂量率及升降源过程吸收剂量对距离分布情况,说明升降源过程吸收剂量尤其在短时间、近距离、小剂量等辐照情况下不可忽视。     

热损补偿型铝吸收剂量量热计的研制

叙述了热损补偿型铝吸收剂量量热计的结构及测量原理，给出了量热计在１０－３５℃工作温区的电加热标定因子，得到了６０Ｃｏγ辐照室中剂量率对距离的分布。     

辐射加工级电子束吸收剂量量热计的研制

叙述了辐射加工级电子束吸收剂量量热计的设计原理,给出了用自行研制的石墨和盒式水量热计测定电子束吸收剂量的方法和结果。用不同吸收体材料和几何参数是热计测量参考材料的吸收剂量,所得结果在０．８％以内符合。并对现有的吸收剂量深度分布测量模体的关键结构作了改进。由测量结果刻度ＧＡＦ－ＤＭ－１２６０和ＦＷＴ－６０辐射显色薄膜得到的电子束吸收剂量响应曲线与＾６０Ｃｏγ射线响应一致。研制的量热计及其测试技术可作     

新型自补偿γ量热计的刻度及测量

用电加热方式对新型自补偿γ量热计算计进行了刻度，测量了低功率反应堆的Ｋ１１孔道和７号孔道内不锈钢的γ释热率，在相同γ释热条件下，使γ释热率的测量误差由没刻度时的±８．０％减小到±１．０％。     

新型硅吸收剂量量热计的电校准

叙述了新型硅吸收剂量量热计的结构及电校准原理;给出了量热计在０－３５℃工作温区的 热校准因子,拟事出硅比热随温度变化关系式。并对实验误差进行了讨论。     

γ量热计及HFETR中γ释热率的测量

本文介绍了适用于高 γ 释热率测定的量热计设计及在高通量工程试验反应堆(HFETR)的G_7,辐照孔道中的 γ 释热率测量,其测量误差在±4.5%以内.     

微量热计测量低活度氚

针对国际热核聚变实验堆氚增殖系统(ITER-TBS)中微量氚活度的绝对测量需求,设计研制了微量热计。采用固体含氚样品对微量热计的输出热电势(Eout)-输入热功率(P)进行标定,Eout-P关系式具有很好的线性关系,灵敏度系数达到0.13V/W。研制的微量热计最低检测限低于0.2μW,量热杯体积大于500mL,该性能指标预期可定量测量ITER-TBS系统中各种复杂形态的微量氚活度,具有很好的应用前景。     

大功率α、β量热计的研制

研制了一台用于α、β核素测量的大功率量热计,量热计样品池尺寸空间为直径75mm、高120mm.性能测试表明,该量热计功率测量范围为1～300 W,当样品热功率不小于10 W时,测量精度优于1.0%.     

量热法测量贮氚容器中的氚

设计建造了 1台样品池容积为1 95mm× 42 0mm的大型氚量热计。该量热计测量样品热功率下限为 6mW。样品热功率在 1 60～ 3 5 0 0mW范围内时 ,信号输出与样品热功率的线性相关系数大于0 9999。当样品热功率不低于 1 60mW时 ,精密度好于 0 2 %。它适用于非对称置样方式的样品中氚的测量。对大容积铀化学床中氚的实测结果表明 :该量热计具有较好的准确性。     

钚量热计的研制

设计研制了1台结构简单、操作方便、样品池内径185 mm和高200 mm用于钚热功率测量的量热计.性能测试表明钚量热计的样品热功率测量下限为4 mW、测量上限高于9 W,灵敏度约为202 mV*W-1,线性范围为4 mW～9 W.使用该量热计测量了钚样品的热功率,并与用分析化学和称量法测得的样品热功率进行了比较,结果表明该量热计测量钚样品热功率具有较高的测量精度,当样品热功率不小于200 mW时,精密度优于0.5%.     

Dielectric microcalorimeter utilizing a quantum ferroelectric thermometer

A dielectric capacitance thermometer was fabricated using KTa_0.99Nb_0.01O₃ (KTN) quantum ferroelectrics. The electric capacitance of the KTN thermometer was measured as a function of temperature from 0.1 to 300?K using the four-terminal-pair method. The KTN thermometer exhibited a dependence of the electric capacitance on the temperature that showed promise for using the thermometer as a microcalorimeter. A prototype of the dielectric microcalorimeter (DMC) was assembled with the KTN thermometer and irradiated with alpha rays with an energy of 5.5 MeV at a temperature of 100 mK. When applying a DC bias voltage to the DMC, the detection signals could be observed at the output of the preamplifier. A response of the DMC to alpha rays was obtained despite the poor signal-to-noise ratio caused by long wirings for the detection signal readout inside the refrigerator.     

Development of Thin Film Thermometer and Its Application to Radiation Loss Measurement in JFT-2 Tokamak

A thin film thermometer with high sensitivity and small response time has been developed. A nickel film was deposited in a vacuum on a backing plate of stainless steel 0.05 mm thick. The pattern of nickel film was so designed to provide sufficient accuracy. A small heat flux of 0.5 W/cm² is measurable with a response time of less than 1 ms. The thermometer was applied to radiation loss measurement in JFT-2 tokamak. The power loss due to the radiation was found to be about 30% of the total power input.     

Reef coral δ15O thermometer in Hainan island waters,South China Sea

An 18-year-long (1981-1998) study was conducted in Hainan Island wa ters (22°20＇N, 110°39′E) to determine the relationship between δ18O in skeletal arag onite carbonate and sea surface temperature (SST) in porites lutea of reef-building corals. δ18O values in skeletal aragonite carbonate were measured by means of mass spectrometry. Coral samples grew at 5m depth at Longwan Bay. Monthly measure ments of the SST from 1960 to 1998 were taken at Qinglan Bay adjacent to the place of the collected samples. The thermometer shows that SST=-4.16 δ18OpDB + 4.9 (r=0.80) and dδ18O/dT=-0.24 permil/°C. The δ18O thermometer is strongly influ enced by the rainfall and runoff. Using the thermometer, the SST in the past hundred years with monthly resolution will be reconstructed and the climatic change in the northern area of South China Sea will be hindcasted     

γ辐射场轴向空间分布随源条件变化规律的计算分析

放射性材料的自发γ辐射场中包含有该材料的形状信息,探索γ辐射场分布与放射性材料形状的关联性对于材料对称性属性的被动测量具有重要意义。论文采用Monte Carlo方法对特定形状的放射性材料的γ辐射场进行了模拟,计算了不同形状、大小、不同自吸收层厚度等条件下源的γ辐射场轴向空间分布,分析了形状、大小等因素对γ轴向空间分布曲线走势的影响,解释了计算结论。     

瞬发伽玛活化分析中3种探测器性能比较

利用中国先进研究堆(CARR)热中子束流孔道首次开展了瞬发伽玛中子活化分析(PGNAA)实验。对NH4Cl、Si、Fe、Al等4种样品进行了辐照,同时采用HPGe、LaBr_3、BGO 3种探测器对样品进行实时测量,在瞬发伽玛射线的能量为0.002~10 MeV范围内研究了3种探测器在宽能区的能量线性、能量分辨率、探测效率等性能。     

三代核电先进堆型热管段温度搅混及温度测量特性研究

为预判三代核电先进堆型热管段温度计设置的合理性，本研究采用计算流体动力学（CFD）分析技术，构建了堆芯出口至热管段温度计位置的分析模型，开展了不同堆芯出口温度、流量分布条件下，热管段冷却剂温度搅混特性及搅混及温度测量特性。研究结果表明，热管段冷却剂出现明显的温度分层现象，但温度计测量的平均值相对其所在管道截面平均温度的偏差较小。因此，三代核电先进堆型热管段温度计设置合理，可有效测量冷却剂温度。      

^6Li和^7Li双玻璃闪烁体γ补偿法测量中子注量

依据＾６Ｌｉ玻璃闪烁体中子，γ皆灵敏，而＾７Ｌｉ玻璃闪烁仅对γ灵敏的特性，研究成功用＾Ｌｉ，＾７Ｌｉ双玻璃闪烁体γ补偿法，实现在强γ辐射场干扰下，对弱中子注量率探测的方法，当＾６０Ｃｏγ在中子信号幅度区的干扰计数率，占中子计算数率的１８．７％时，该方法对净中子注量测量结果导致的误差约为１％。     

Evaluation of prompt fission gamma rays for use in simulating nuclear safeguard measurements

Nondestructive assay methods that rely on measurement of correlated gamma rays from fission have been proposed as a means to determine the mass of fissile materials. Sensitivity studies for such measurements will require knowledge of the multiplicity of prompt gamma rays from fission; however, a very limited number of multiplicity distributions have been measured. A method is proposed to estimate the average number of gamma rays from any fission process by using the correlation of neutron and gamma emission in fission. Using this method, models for the total prompt gamma ray energy from fission adequately reproduce the measured value for thermal neutron induced fission of ²³³U. Likewise, the average energy of prompt gamma rays from fission has been adequately estimated using a simple linear model. Additionally, a method to estimate the multiplicity distribution of prompt gamma rays from fission is proposed based on a measured distribution for ²⁵²Cf. These methods are only approximate at best and should only be used for sensitivity studies. Measurements of the multiplicity distribution of prompt gamma rays from fission should be performed to determine the adequacy of the models proposed in this article.     

Characterization of an Am-Be PGNAA set-up developed for in situ liquid analysis: Application to domestic waste water and industrial liquid effluents analysis

A prompt gamma neutron activation analysis (PGNAA) set-up with an Am-Be source developed for in situ analysis of liquid samples is described. The linearity of its response was tested for chlorine and cadmium dissolved in water. Prompt gamma efficiency of the system has been determined experimentally using prompt gamma of chlorine dissolved in water and detection limits for different elements have been derived for domestic waste water. A methodology to analyze any kind of liquid is then proposed. This methodology consists mainly on using standards with water as bulk or in the case of absolute method, to use gamma efficiency determined with prompt gammas emitted by chlorine dissolved in water. To take into account the thermal neutron flux variations inside the samples, flux monitoring was carried out using a He-3 neutron detector placed at the external sample container surface. Finally, to correct for the differences in gamma attenuation, average gamma attenuations factors were calculated using MCNP5 code. This method was then checked successfully by determining cadmium in industrial phosphoric acid and our result was in good agreement with that obtained with inductively coupled plasma (ICP) method.