加速器生产~(109)Cd用Ag靶制备

Ag靶用于加速器生产109Cd,核反应为109Ag(p,n)109Cd。本工作采用电沉积法制备Ag靶。通过对影响电沉积Ag靶层质量及厚度的各种因素的实验,确定了Ag靶制备工艺条件如下:ρ(Ag )=20～50g/L,ρ(KNO3)=10～30g/L,?(NH4OH)=0.1～0.2。用此工艺条件,制备出质量厚度大于100mg/cm2、表面     

6 加速器生产加^109Cd用Ag靶制备

Ag靶用于加速器生产^109Cd，核反应为^109Ag（p，n）^109Cd。本工作采用电沉积法制备Ag靶。通过对影响电沉积Ag靶层质量及厚度的各种因素的实验，确定了Ag靶制备工艺条件如下：ρ（Ag^＋）=20～50g／L，ρ（KNO3）=10-30g／L，φ（NH4OH）=0．1～0．2。用此工艺条件，制备出质量厚度大于100mg／cm^2、表面光滑、镀层致密的Ag靶。     

电沉积法制备加速器生产64Cu的镍靶

为制备加速器生产64Cu辐照用Ni靶,采用电沉积法研究了电沉积过程中影响Ni靶层质量和质量厚度的主要因素,确定了Ni靶制备工艺条件和参数,为Ni浓度40～50 g/L,盐酸浓度0.05～0.5 mol/L,电沉积温度20～50℃,搅拌器旋转速度150～350 r/min,电流密度10～35 mA/cm2。在此工艺条件下制备出的Ni靶件表面光滑、平整,靶层致密、牢固,可应用于回旋加速器生产64Cu。     

电沉积LEU UO_2靶件生产医用~(99)Mo的工艺研究

~(99)Mo是一种重要的医用放射性同位素。采用低浓铀(LEU)靶件生产裂变~(99)Mo是发展趋势。本工作进行了电沉积UO_2靶件制备、靶件溶解以及99Mo化学分离等工艺研究,确定了电沉积LEU UO_2靶件制备医用裂变99Mo的工艺流程。研究表明,于不锈钢管内壁上电沉积UO_2,在p H=7、电流0.5~2 m A/cm2、温度75~90℃、镀液中U浓度5 mg/mL条件下,经过约210 h电沉积,不锈钢管内壁上UO_2沉积层质量达到42 mg/cm~2;采用6 mol/L HNO_3溶解UO_2镀层。采用α-安息香肟沉淀法实现~(99)Mo与大量裂变产物的初步分离,采用阴离子交换法与活性炭色层法联用实现99Mo的纯化;纯化后的99Mo溶液中,杂质~(131)I、~(90)Sr、~(95)Zr、~(103)Ru、~(238)U活度与~(99)Mo活度比值分别为4.47×10~(-6)%、7.40×10~(-7)%、8.67×10~(-7)%、2.57×10~(-6)%、1.69×10~(-14)%,均小于《欧洲药典》规定值,满足医用要求。本工作建立了电沉积LEU UO_2靶件生产高纯医用裂变99Mo的工艺流程,为今后采用LEU技术生产医用裂变99Mo,进而实现其自主规模化生产打下了基础。     

水溶液体系制备铀电镀靶

对影响电沉积铀的主要因素进行了试验和讨论,在电沉积法制备铀靶的初期实验中,选用不锈钢作为电沉积铀的靶片,用UO2(NO3)2和(NH4)2C2O4作为镀液,pH值为2~3。对影响电沉积铀的主要因素进行了试验和讨论,并用分光光度法分析了电镀残液中的铀含量,最终制得的铀靶的沉积厚度达到8~10mg/cm2,镀层牢固、均匀,电镀效率大于80%。     

核数据测量用钚靶的制备

钚的核数据测量是核科学领域一项重要的研究内容，要获得钚的相关核数据，需将钚制备成钚靶置于加速器或反应堆中进行辐照，因此在测量过程中钚靶必不可少。根据测量相关需求，需要将m≥4 μg的钚制备成活性区直径D≤5 mm的钚靶。本工作对于小面积Pu靶的制备进行了大量的实验工作，通过对异丙醇、硫酸铵、硫酸钠三种不同电沉积体系的研究，确定了以硫酸钠为电沉积液的电沉积体系，并对装置进行改进以及对相关工艺条件进行研究，确定了Pu靶制备工艺：在pH=2.0~3.0的硫酸钠电沉积液中、750 mA/cm²的电流密度、65 ℃下，电沉积150 min，并通过液闪谱仪对电沉积率进行了检测。结果表明，该方法对于Pu的电沉积率可达98%以上。     

电沉积法制备镉靶

对加速器生产111In所用镉靶制备工艺进行了研究.通过研究电沉积过程中影响Cd靶质量及厚度的各种因素,确定了最佳工艺条件.所研制的镉靶厚度大于57 mg/cm2,表面光亮、致密、牢固.     

水溶液中Np、Pu、Am和Cm同时电沉积制备α测量源

为制备高分辨率Np、Pu、Am和Cm的α混合测量源,研究了电沉积液介质浓度、pH值、电流密度、电沉积时间等条件对电沉积效率及沉积源质量的影响。结果表明,在pH为2.0~2.5的0.2mol/L硫酸铵介质中,电流密度为0.40~0.50A/cm2,室温条件下电沉积60min,~(237)Np、~(238)Pu、~(243)Am和~(244)Cm在阴极不锈钢片上的电沉积效率均大于96%,制备的α测量源能量分辨率较好。     

电沉积铀靶制备技术研究

研究了在水溶液体系中采用电沉积法制备铀靶的方法。以0.15mol/L草酸铵为电解液,铂丝为电极,通过考察阴极处理工艺、电流密度、电沉积时间、pH、温度、搅拌速度、镀液中UO2(NO3)2浓度等对电沉积效率及镀层质量的影响,确定了制备电沉积铀靶的最佳工艺参数,其中,沉积效率通过紫外分光光度法测得。在pH=2～3、电流密度60mA/cm2、保持温度60℃、镀液中UO2(NO3)2浓度约1.67mg/mL时沉积效率可达约98%。采用红外光谱、X射线能谱和扫描电镜等对铀沉积层进行了测试。结果显示,铀以水合聚合物的形式存在,可能的结构为[UO2(H2O)4-O-UO2(H2O)4-O],铀的沉积层的纯度较高,除检测到铀(65.35%)、氧(27.38%)、碳(5.46%)和铂(1.81%)外未引入其他杂质,镀层表面平整、致密,与衬底结合牢固。单次铀的电沉积层厚度可达6mg/cm2,采用高温烧结后重复电镀的方法可将电沉积铀的密度提高到6～8mg/cm2。     

电沉积 LEU UO2 靶件生产医用99Mo的工艺研究

⁹⁹Mo是一种重要的医用放射性同位素。采用低浓铀（LEU）靶件生产裂变⁹⁹Mo是发展趋势。本工作进行了电沉积UO₂靶件制备、靶件溶解以及⁹⁹Mo化学分离等工艺研究,确定了电沉积LEU UO₂靶件制备医用裂变⁹⁹Mo的工艺流程。研究表明,于不锈钢管内壁上电沉积UO₂,在pH=7、电流0.5~2 mA/cm²、温度75~90 ℃、镀液中U浓度5 mg/mL条件下,经过约210 h电沉积,不锈钢管内壁上UO₂沉积层质量达到42 mg/cm²;采用6 mol/L HNO₃溶解UO₂镀层。采用α-安息香肟沉淀法实现⁹⁹Mo与大量裂变产物的初步分离,采用阴离子交换法与活性炭色层法联用实现⁹⁹Mo的纯化;纯化后的⁹⁹Mo溶液中,杂质¹³¹I、⁹⁰Sr、⁹⁵Zr、¹⁰³Ru、²³⁸U活度与⁹⁹Mo活度比值分别为4.47×10^-6%、7.40×10^-7%、8.67×10^-7%、2.57×10^-6%、1.69×10^-14%,均小于《欧洲药典》规定值,满足医用要求。本工作建立了电沉积LEU UO₂靶件生产高纯医用裂变⁹⁹Mo的工艺流程,为今后采用LEU技术生产医用裂变⁹⁹Mo,进而实现其自主规模化生产打下了基础。     

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.     

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.     

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.     

微型X射线管空气比释动能和能谱的测量

为研究微型X射线管的特性,通过电离室测量光管出射口30 cm远处的空气比释动能,使用高纯锗探测器分别测量了Ag过滤和Cu过滤下的X射线能谱。结果表明,空气比释动能随电流的增加有线性增加的趋势,能谱图明显的观察到银的两个特征X射线。完成了微型X射线管空气比释动能和能谱的测量方法以及实验测量的工作,为微型x射线管下辐射质的建立提够了条件基础。     

Gamma-ray attenuation technique for measuring void fraction in horizontal gas-liquid two-phase flow

The measurement of void fraction is of importance to the oil industry and chemical industry. In this article, the principle and mathematical method of determining the void fraction of horizontal gas-liquid flow by using a single-energy γ-ray system is described. The γ-ray source is the radioactive isotope of 241Am with γ-ray energy of 59.5 keV. The time-averaged value of the void fraction in a 50.0-mm i.d. transparent horizontal pipeline is measured under various combinations of the liquid flow and gas flow. It is found that increasing the gas flow rate at a fixed liquid flow rate would increase the void fraction. Test data are compared with the predictions of the correlations and a good agreement is found. The result shows that the designed γ-ray system can be used for measuring the void fraction in a horizontal gas-liquid two-phase flow with high accuracy.