塑闪墙在束性能测试

在HIRFL通用散射室的终端调试时完成了0°附近Pilot U塑闪墙的性能测量,给出了位置分辨为Δx=3cm,时间分辨为600ps,并能分辨出Z≤6的几种主要粒子,测得100×5×1cm~3的Pilot U有效光速为16.37cm/ns,有效衰减长度为92.4cm,并解决了同一条塑闪在0°附近的粒子多击问题。     

5×5阵列PHOSWICH闪烁探测器望远镜

描述了一个 5× 5阵列带电粒子 PHOSWICH闪烁探测器望远镜结构。它的每一个单元由 1片厚度为 1mm,面积为 2 4 mm× 2 4 mm快塑料闪烁体 NE10 2 A和 1个前表面为 2 4 mm× 2 4 mm,后表面为 37mm×37mm,厚度为 4 0 mm的 Cs I( Tl)晶体组成的。在兰州放射性离子次级束流线 ( RIBL L )上测试到 Z/ΔZ =2 0     

自研塑料闪烁体探测器中子/γ甄别能力测试

塑料闪烁体在中子探测领域具有重要应用前景。对于自研两种尺寸(?2.54 cm×2.54 cm、?5.08 cm×5.08 cm)的塑料闪烁体进行了测试。采用光电倍增管(Photomultiplier Tube,PMT)搭建了探测系统，利用高速示波器采集功能对自研塑料闪烁体进行能量刻度，通过测量¹³⁷Cs γ放射源的脉冲幅度谱并与MCNP5模拟谱对比，以获取康普顿边缘位置信息，实现准确的γ射线能量标定。利用电荷积分法对从241Am-Be中子源上获取的数据进行分析，采用品质因子(Figure Of Merit,FOM)、中子峰谷比、中子漏计数率等参数量化不同能区的n-γ甄别效果，对比自研塑料闪烁体相对于EJ-299-33A的探测效率。结果表明：?2.54 cm×2.54 cm自研塑料闪烁体相比于?5.08 cm×5.08 cm自研塑料闪烁体具有较高的FOM值；两种自研塑料闪烁体相对于EJ-299-33A的探测效率分别约为0.49和1.0，可见自研的?5.08 cm×5.08 cm塑料闪烁体与同尺寸的商用塑料闪烁体EJ-299-33A性能相当。     

高时间分辨的聚变反应历程测量系统设计

为了测量惯性约束聚变实验中聚变反应的时间过程,提出了一种高时间分辨的聚变反应历程测量系统设计。该系统主要由闪烁体及鼻锥、光学成像系统和条纹相机系统三部分组成。用于能量分别为2.45MeV和14.03MeV的聚变中子测量时,系统的时间分辨分别优于55ps和40ps,对应的测量下限中子产额分别为1.5×109和4×108。     

用于环境X,γ辐射测量的SG101型可携式闪烁剂量率仪

仪器的探头由表面涂ZnS(Ag)的柱形塑料闪烁体(ST401型,φ75×75mm),高增益低噪声光电倍增管(GDB52LD)和铝蔽光套组成。测量电路为直流放大器。为减小光电倍增管暗电流和放大器栅流产生的仪器自身本底,设计了随温度变化的自动补偿电路。仪器的主要技术指标满足IEC标准(草案,SC 45B,C.O.52)的要求。有效测量范围:0.3×10~(-8)Gy·h~(-1)～300×10~(-8)Gy·h~(-1);相对固有误差不大于±3%;能量响应:50keV～1.25MeV,小于 ±10%;对宇宙射线空气吸收剂量率的测值(水面上)与高气压电离室测值在±5％内相符合;整机重量4kg;备有~(241)Am检查源。仪器可测量环境贯穿辐射天然本底剂量率。     

CeF3闪烁探测器对X射线的电荷灵敏度标定

本文采用脉冲X射线源对光电管CeF3探测器的灵敏度进行了实验标定,得出了CeF3闪烁探测器对X射线的电荷灵敏度.实验中使用的X射线源为СГС-67型三通道脉冲发生器,X射线平均能量200 keV.实验结果表明,对于φ45 mm×10 mm、φ45 mm×5.0 mm、φ45 mm×4.5 mm 和φ45 mm×3.0 mm四种尺寸的CeF3探测器,其电荷灵敏度分别为6.70×10-18 C/MeV、4.68×10-18 C/MeV、4.47×10-18 C/MeV和3.84×10-18 C/MeV.本文还探讨了探测器灵敏度和闪烁体厚度的关系.     

大面积闪烁光纤阵列探测器的在束测试

利用70AMeV²⁶Mg初级束流及其产生的次级束流，在兰州重离子加速器放射性次级束流线（RIBLL）终端测试了大面积闪烁光纤阵列探测器(LASFA)探测单元的时间分辨和位置分辨能力。利用70AMeV²⁶Mg初级束流测试得到的时间分辨约为128ps，对应的位置分辨约为10mm；利用次级束流测试得到的时间分辨约为158ps，对应的位置分辨约为13mm，具有很好的时间分辨和空间角分辨能力。结合RIBLL的ΔESi探测器，给出了ΔE_Si-TOF二维谱，并将测试结果与RIBLL的粒子鉴别系统进行详细比较。结果表明，大面积闪烁光纤阵列作为轻带电粒子的飞行时间终止探测器，性能优于RIBLL上采用的时间拾取探测器，可更清楚地鉴别次级束流。     

含~(60)Co和~(152)Eu放射性废液的水泥固化配方研究

针对含60 Co 3 8× 10 5Bq/L、152 Eu 6 67× 10 5Bq/L、总放射性活度为 2× 10 7Bq的放射性废液进行了水泥固化配方及工艺试验研究。结果表明 :水泥浆流动度和初凝时间随水灰比增大而增大 ,而固化体的抗压强度则随其增大而降低。优选配方的水泥固化体各种性能均满足中低放废液固化体性能要求 :水泥浆流动度≥ 130mm ;水泥固化体 2 8d抗压强度 >7MPa ;4 2d浸出率60 Co为1 84× 10 - 4cm/d、152 Eu为 2 76× 10 - 5cm/d(剂灰比 0 15 ) ,60 Co为 5 4 7× 10 - 4cm/d、152 Eu为1 5 5× 10 - 4cm/d(无添加剂 ) ;总 β的累积浸出分数 (4 2d)分别为 1 7× 10 - 2 cm(剂灰比 0 15 )和3 5× 10 - 2 cm(无添加剂 )     

方形闪烁光纤阵列出射荧光特性数值模拟

为对方形塑料闪烁光纤阵列的出射荧光特性进行分析,利用Geant4蒙特卡罗程序包将中子在闪烁光纤阵列中的能量沉积弥散过程和荧光（E≤100eV）在光纤内部的传播过程进行耦合输运模拟。分析14MeV中子入射点的位置对荧光强度分布的影响,找出计算闪烁光纤阵列调制传递函数的1个等效点。讨论了荧光强度分布、荧光收集效率与角分布之间的关系。以5cm厚闪烁光纤阵列为例,讨论了闪烁光纤阵列的调制传递函数和平板闪烁体的能量沉积分布函数、抽样函数之间的关系。结果表明,闪烁光纤阵列的调制传递函数近似可用平板闪烁体的能量沉积分布函数经函数rect(x,y)抽样后的结果作二维傅里叶变换得到。     

叠层塑料闪烁探测器望远镜

描述了由１ｍｍ厚的快塑料闪烁体ＮＥ１０２Ａ和１００ｍｍ厚的快塑料闪烁体ＮＥ１１５组成的叠层闪烁探测器望远镜。光电倍增管阳极信号用传统的快慢门－ＱＤＣ方法处理，对Ｚ≤２０碎片得到了较好的粒子鉴别，元素分辨Ｚ／ΔＺ￣４５。     

Identification of radiation treatment of wheat （Triticum aestivum. L）and rice （Oryza sativa. L） samples using thermoluminescence of contaminating minerals

Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food. Because of the rapid commercialization of irradiated foods throughout the world, compliance of different regulations relating to use of technology in different countries and demand of consumers for clear labelling of irradiated foods, there is need for the development of analytical methods to detect radiation treatment of food. Among several methods studied so far, thermoluminescence （TL） is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles. In this study, the irradiated and unirradiated wheat and rice samples were analyzed using the TL method. The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture （NIFA）, Peshawar. The mineral contaminants were isolated by jet water, ultrasonic treatment, and density gradient. TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50-500℃ using a TL reader. Generally, the glow curves for irradiated samples showed much higher TL intensities （TL1） than the unirradiated samples. The results were normalized by rerradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves （TL2）. The ratio of the area of first glow curve to that of second glow curve （TL1/TL2） was calculated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples. Finally, the shapes of the glow curves for irradiated and unirradiated samples were also analyzed. On the basis of these results （comparison of TL-intensities, TL1/TL2 ratios and shapes of the glow curves）, all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.     

有效探测面积大于1000 cm2的正比计数器测量系统性能测试

为对自制的活性面积高达1 000 cm²的大面积源进行表面发射率定值,同时作为现有2πα、2πβ表面发射率标准装置能力的扩充,研制了一套内置式大面积2π多丝正比计数器测量系统,并利用活性区直径为8 mm的²⁴¹Am点源及活性区面积为10 cm×15 cm的大面积²⁴¹Am和⁹⁰Sr-⁹⁰Y源对其进行计量学性能测试。结果表明：计数器内计数响应均匀性优于±0.4%,有效探测面积达1 400 cm²;所得²⁴¹Am源高压坪曲线的坪长为1 400 V,坪斜为0.27%/100 V,坪区内计数变化为0.87%;⁹⁰Sr-⁹⁰Y源高压坪曲线的坪长为300 V,坪斜为0.75%/100 V,坪区内计数变化为0.80%;10次测量重复性好于0.4%,8 h内短期稳定性好于0.3%,1 a内长期稳定性好于0.8%。     

Preparation of Zn/TiO2 powder and its photocatalytic performance for oxidation of P-nitrophenol

Zn-doped TiO2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis, BET, XRD in this study. Under the irradiation of simulant sunlight, the photocatalytic activity for the degradation of p-nitrophenol was studied too. After irradiation for 2.5 h, the degradation percentage of p-nitrophenol could rise to more than 80 %. The results showed that the spectrum absorption band edge of Zn/TiO2 powder does not broaden obviously comparing with pure TiO2 powder. Zinc exists as Zn （11）. When calcined at 973 K, there is a new phase as ZnTiO3 in Zn/TiO2 catalyst. The order of photocatalytic activity of Zn/TiO2 catalysts calcined at different temperatures for p-nitrophenol is 773 K 〉 673 K 〉 873 K 〉 573 K 〉 973 K and the photocatalytic activity of Zn/TiO2 catalyst calcined at 773 K is better than TiO2 catalysts heated at the same temperature, and outclasses that of commercial TiO2 catalyst. It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irradiation of simulant sunlight.     

Current status of radiation therapy for prostate cancer

Radiotherapy for the treatment of prostate cancer has been extensively explored in the past. Along with the comprehensive understanding of the biology of prostate cancer and rapid advances in terms of technology, the out- come of treatment for the patients with prostate cancer has improved. The authors review radiotherapy as the primary treatment for the disease, with particular emphasis on the technological advances from both the radiobiological and radiophysics aspects. Nonconventional fractionated irradiation like hyper- or hypo-fractionation has been imple- mented in the clinic, the final results still need to be confirmed in the future. Technological advances like IMRT, IGRT, in the last two decades have significantly improved the delivery of external radiotherapy to the prostate. This has re- sulted in an overall increase in the total dose that can be safely delivered to the prostate, which has led to modest im- provements in the biochemical outcome. However, establishing the standard therapy for prostate cancer remains con- troversial. It is hoped that the next decades will bring continued advances in the development of biologicals that will further improve current clinical outcomes.     

Interaction between uranium and humic acid (Ⅰ): Adsorption behaviors of U(Ⅵ) in soil humic acids

The adsorption behaviors of uranium on three soil humic acids (HAs), which were extracted from soils of different depths at the same site, were investigated under various experimental conditions. The adsorption results showed that U(Ⅵ) in solutions can be adsorbed by the three soil HAs, with the order of FHA (HA from 5 m depth of soil) ＞SHA (HA from the surface) ＞THA (HA from 10 m depth of soil) for adsorption efficiency in each desirable condition, and the adsorption reached equilibrium in about 240 min. Although the maximum adsorption efficiency was adsorption could be described with Langmiur isotherm or Freundlich isotherm equation. The L/S (liquid/solid, mL/g)ratio and pH were important factors influencing the adsorption in our adsorption system besides uranium concentration. The adsorption efficiency decreased with the increase of the L/S ratio and pH at the pH range of 2.0-3.0 for SHA and THA or 2.5 - 6.0 for FHA. However, no significant difference in adsorption of U(Ⅵ) was observed at the experimental temperature. All the results implied that humic substances have different characteristics in samples even collected at the same site.     

水平管内含空气蒸汽强制对流冷凝换热模型研究

为研究含空气蒸汽在水平管内强制对流冷凝换热特性,基于对传热传质过程的分析,建立了管内为环状流与波状流条件下的流动冷凝换热模型。从潜热、显热和液膜3个环节对整个换热过程进行建模,最终得到计算局部冷凝换热系数的理论关系式。模型预测结果与实验数据的对比表明,二者相对偏差在±20%以内,验证了该换热模型的准确性与适用性。通过进一步的研究发现：从换热管入口至出口,随着冷凝的进行,管内换热主要热阻由液膜热阻向气液界面的凝结热阻转变;主流气体对流换热过程基本可忽略。     

The preclinical pharmacological study of dopamine transporter imaging agent 18F-FP-β-CIT

The paper is to study pharmacologic characteristics of 18F-FP-β-CIT (18F-N-(3-fluoropropyl)-2β- carbomethoxy-3β- (4-iodophenyl)nortropane) as an imaging agent for dopamine transporter. The radiochemical purity of 18F-FP-β-CIT in aqueous solution was over 95% after standing at room temperature for 4h. Biodistribution displayed rapid uptake in rat brain (1.375 %ID/organ at 5min and 0.100 %ID/organ at 180 min) and the striatal uptake was 1.444,0.731, 0.397, 0.230 and 0.146 %ID/g at 5, 30, 60, 120 and 180 min, respectively. The values of striatum/cerebellum,striatum/frontal cortex and striatum / hippocampus in rat's brain at 30 min were 3.38, 2.17 and 2.40 respectively. The uptake in striatum can be blocked by β-CFT, suggesting that 18F-FP-β-CIT binds to DAT peculiarly. The compound was rapidly cleared from monkey's blood. The striatal uptake was bilaterally decreased in the left-sided lesioned PD rats, compared with normal control. Brain PET imaging studies in normal monkey showed that 18F-FP-β-CIT was concentrated in striatum. The test of undue toxicity showed that the dose received by mice was 1250 times as by human, which indicates that 18F-FP-β-CIT is very safe. So 18F-FP-β-CIT is a promising PET imaging agent for DAT with safety and validity.     

Information for authors

<正>1.NUCLEAR SCIENCE AND TECHNIQUES(NST),a bimonthly journal,is devoted to all aspects of nuclear science and technology,theoretical or experimental.Its special interest lies in the subjects of synchrotron radiation science and technology;low energy accelerators,radiation technology and applications;radiochemistry,radiopharmaceuticals and nuclear medicine;nuclear electronics and instrumen-     

PLASMA SCIENCE AND TECHNOLOGY AUTHOR INDEX TO VOLUME 16(2014)

正~~     

Web Services interface of SSRF archive data analysis system

Accelerator database stores various static parameters and real-time data of accelerator. SSRF (Shanghai Synchrotron Radiation Facility) adopts relational database to save the data. We developed a data retrieval system based on XML Web Services for accessing the archive data. It includes a bottom layer interface and an interface applicable for accelerator physics. Client samples exemplifying how to consume the interface are given. The users can browse, retrieve and plot data by the client samples. Also, we give a method to test its stability. The test result and performance are described.