电制冷高纯锗探测器宽能区效率刻度

介绍电制冷高纯锗探测器在宽能区探测效率曲线刻度方法,提出并验证了在无低能标准源时可采用~(157)Gd冷中子瞬发γ源进行代替。实验中使用探测效率分段对数拟合及整体对数多项式拟合,对两种拟合方式进行对比,并使用~(152)Eu缓发源和~(157)Gd、~(35)Cl冷中子瞬发γ源能量相交区域进行拟合和误差计算。实验结果表示:整体拟合的计算相对简单,但分段拟合获得数据更为准确,相关性更好。无低能标准源可用时,使用~(157)Gd(n,γ)源效果更佳。     

f区元素-羟基吡啶酮体系的配合物研究——Ⅱ.钆(Ⅲ)、钍(Ⅳ)-羟基吡啶酮配合物的合成和性质研究

本文在等摩尔的钆(Ⅲ)或钍(Ⅳ)和羟基吡啶酮(1-羟基-2-吡啶酮(1,2-HOPO)和3-羟基-2-吡啶酮(3,2-HOPO))的体系中,及在高pH条件下,合成了Th(1,2-OPO)(OH)_3·6H_2O,Th(3,2-OPO)(OH)_3·6H_2O,Gd(1,2-OPO)(OH)_2·3H_2O和Gd(3,2-OPO)(OH)_2·4H_2O等四种固体配合物。采用重量法,碳、氢、氮元素组份分析法和EDTA络合滴定等分析方法测定了配合物的组成。用溴化钾、碘化铯压片法研究了固体配合物的红外光谱性质。对固体配合物的溶解性和溶解液的紫外光谱作了研究。     

闪烁测井仪的活动铅屏

在定量测定天然γ放射性时使用Naj(TI)单晶体探测器,其铅屏厚度为2—3毫米。采用铅屏,可使换算系数K(微伦琴/小时/0.01％元素含量)保持常数值,K值在定量解释测井结果时是必需的。在应用γ测井进行岩性分层时,以及在用中子-γ测井和γ-γ测井方法研究时,测量物理参数时必须使用敞开的(不带屏)单晶体,以便对岩石成分的变化达到最大的灵敏度。因此,产生了在降—升测井工序中使用不带屏单晶体(中子-γ测井、γ-γ测井、γ测井法)和     

Gd3+掺杂YBCO体系超导电性的正电子研究

为探究稀土离子Gd3 的Y位掺杂对YBa2Cu3O7-δ(YBCO)体系晶体结构和局域电子结构的影响,利用正电子湮没和X-射线衍射(XRD)实验对Y1-xGdxBa2Cu3O7-δ(x=0-1.0)系列样品进行了系统研究.XRD实验表明,Gd离子的Y位替代使得样品晶胞参数增大,但所有样品均保持与YBCO相同的单相正交结构.输运测量表明,各实验样品超导转变温度Tc均在90 K以上,且整体上随Gd3 离子含量的增加而增加.正电子实验结果给出局域电子密度ne随Gd掺杂浓度x的增加而减小.     

CMP流程处理高放废液后的锕系镧系的分离研究

研究了以HDEHP为萃取剂、DTPA为络合剂,在0.2—0.5mol/l HNO_3酸度下实现An~?(Ⅲ)、Ln~(2?)(Ⅲ)分离的工艺条件。结果表明,Am(Ⅲ)、Gd(Ⅲ)和En(Ⅲ)的分配比和HDEHP浓度的平方成正比,和酸度的3次方成反比。随温度的升高和料液中金属离子起始浓度的增大而降低。Am(Ⅲ)、Gd(Ⅲ)和En(Ⅲ)的萃取反应热依次为-7.1×10~3J·mol~(-1),-9.2×10~3J·mol~(-1)和-1.9×10~3J·nol~(-1)。采用1.0 mol/l HDEHP-煤油为萃取剂,pH3.2-3.6,0.15 mol/l DTPA-2 mol/l 乳酸为反萃剂,用模拟料液进行串级实验。Am(Ⅲ)近100%被回收,和Am(Ⅲ)共存于水相的Ln~(2?)(Ⅲ)少于3%。根据实验结果提出了概念流程。     

~(11)C-Ketamine—2-(2-氯苯基)-2-(~(11)C-甲氨基)环己酮的合成

为了探索新的脑示踪剂,并研究示踪剂在生物体内分布、吸收和代谢,我们进行了麻醉药物~(11)C-Ketamine的合成研究,其合成步骤如下: 邻-氯苯基环己基酮(b_(0.3)96-7℃,n_D~(20) 1.5452)(21g;0.1mol)和溴水(10g,0.625mol)在80ml四氯化碳中,给出1-溴环戊基,邻-氯苯基酮(Ⅰ),化合物(Ⅰ)在过量液氨中进行反应,     

地下水不同流态的同位素示踪探测分析

同位素示踪测井技术是研究地下水运动的有效手段。注入测井的同位素示踪剂会随着测井内水流运动,因此不同流态测井内示踪剂的分布亦不同。由放射性强度随深度变化关系可确定示踪剂在测井内的浓度分布,从而了解测井内水流的运动状态。结合工程实际测量数据,分别分析了层流、紊流及单孔中既有层流又有紊流情况下测井内放射性强度分布特点,给出了流速的计算公式;同时介绍了在混合流时区分层流段和紊流段的方法。对比分析了误判地下水流态带来的流速计算误差,指出正确把握地下水流态是非常重要的。最后总结了利用同位素测井技术解决工程实际问题时需要注意的问题,以及不同水文地质条件下合适的测量方法。     

痕量全氟二甲基环丁烷在Carboxen-569上的穿透特性

借助气相色谱基本原理,实验测定了全氟二甲基环丁烷大气示踪剂通过Carboxen-569碳分子筛吸附管的穿透体积和大气样品采集的安全采样体积。结果表明:示踪剂的穿透体积(VB)与温度(t)满足lgVB=4.525-0.041 2t关系,而与流动相的流速(F)变化(F≤1 500 mL/min)基本无关;示踪剂样品安全采样体积(VS)与采样温度的关系为lgVS=4.551-0.061 6t(F=1 000 mL/min),与流动相流速的关系为lgVS=2.195-2.449×10-4F(t=40℃)。常温采样时,示踪剂的采样损失可以忽略。     

核技术在示踪环境污染物中的应用

【美国《核学会汇刊》1981年第39卷第61页报道】环境科学的历史表明,示踪剂是该领域工作者的重要工具。它主要用于测量流速和弥散系数,跟踪物质在大气层、地下水和生物圈中的运动以及对污染源加以表征。环境科学使用的示踪剂主要有三类:(1)化学示踪剂,如NaCl、KHSO_4、K_2CO_3等,(2)放射性示踪剂,如~3H、~(32)P、~(32)Br等和(3)荧光染料,如荧光素、     

(U,Gd)O_2可燃毒物燃料芯块制造工艺及其主要性能

介绍了中国核动力研究设计院(U,Gd)O2可燃毒物燃料芯块制造生产线所使用的原材料UO2粉末、Gd2O3粉末、(U,Gd)3O8粉末以及添加剂硬脂酸锌和草酸铵的主要性能,同时描述了混料、制粒、成型、烧结和磨削等制造工艺过程及其产品(U,Gd)O2芯块的主要性能,并对制造过程中有关工艺控制参数进行了讨论。     

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.     

The control system for SSRF injection and extraction

This paper introduces the injection and extraction control system design for SSRF,which is a distributed control system aimed at stability and reliability of the pulse power supplies,PPS(Personnel Protection System)and MPS(Machine Protection System).The hardware environment is mainly based on PLC(Programmable Logic Con- troller),and ARM(Advanced RISC Machine)is also applied for studying stability of the power supplies.WinCC and EPICS(Experimental Physics and Industrial Control System)have been selected as the platforms of SCADA(Super- visory Control and Data Acquisition).For unifying the interfacing to the control computer,all front-end equipments are connected via Industrial Ethemet.     

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。     

Investigations on landmine detection by BF3 detector

Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory.     

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.     

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%。     

Assessment of radioactivity levels in some oil samples from the western desert, Egypt

Distributions of natural gamma-emitting radionuclides were determined in 93 oil samples collected from some petroleum fields in the western desert of Egypt. The radioisotope activities in the area under investigation lay in the range of (21 ± 4) to (38 ± 13) Bq?L-1 for 226Ra, (9 ± 2) to (15 ± 5) Bq?L-1 for 232Th, and (154 ± 28) to (303 ± 54) Bq?L-1 for 40K. The mean values were 27, 12, and 201 Bq?L-1, respectively. Among oils, variations in radionuclide ac- tivities could be on account of differences in TDS, HCO3, and Ba, with high or low pH. In this environment, oil prop- erties differently affected the mobilization of natural radionuclides. The range of 226Ra variation had been compared with available data from other countries. The calculated absorbed dose rate ranged from 22.33 to 32.66 nGy?h-1 in lo- cation (B) and (E) respectively, which was less than the accepted value.     

Preparation and properties of 117m Sn(IV)-TTHMP in in-vitro and in small animals

In this work,TTHMP was synthesized and labelled with 117m Sn.The preparation conditions,stability and lipophilicity of 117m Sn(IV)-TTHMP were investigated.Biodistribution of the complex in rabbits and mice was studied.It was found that the quantity of TTHMP and pH value of the prepararion solution had vital effects on the labeling yield of 117m Sn(IV)-TTHMP.It was also found that 117m Sn(IV)-TTHMP was hydrophilic and stable at room temperature and 37℃ in open air 117m Sn(IV)-TTHMP showed unexpectedly high bone uptake and bone-to-blood ratio in the animals.This made it potentially useful as an reagent for skeletal scintigraphy and radiotherapy of bone tumors.     

The role of AGFA high-energy CR in the calibration and quality control of multileaf collimators （MLC）

Linear accelerators equipped with multileaf collimators （MLC） are becoming more common and are widely used in the intensity-modulated radiotherapy （IMRT）. There is an imperative need to ensure the commissioning specification of the linear accelerators for the sake of quality assurance （QA） and quality control （QC）. This paper is aimed to investigate the role of AGFA high-energy CR （Computed Radiography） in calibrating dynamic multileaf collimators and evaluating the accuracy of the leaf position. The result shows that AGFA high-energy CR can easily and conveniently be used to calibrate MLC and verify its position. Hence, the application of AGFA high-energy CR is proved to be an accurate and time-saving method for routine MLC QC, especially when MLC calibration adjustments are required.