同位素208Pb靶的制备

介绍了一种弧形靶框夹芯208pb靶的制备工艺,包括核靶的制备装置和制备方法、核靶厚度和均匀性的控制和测量方法,并对结果进行了讨论.制备采用旋转蒸镀法,该法可以大大提高材料的利用率.所制靶的结构为30μg/cm2 C+361 μg/cm2 208pb+15 μg/cm2 C,同一次所制的靶平均厚度为361μg/cm2,不均匀性小于9.8%.其性能能够很好地满足超重核实验研究的要求.     

分子电镀法制备237Np核靶

研究了在异丙醇介质中电沉积制备^237Np核靶的方法，分析了电流、电压、电镀时间、体系中的含水量等因素对沉积率的影响，并给出了^237Np的纯化及不同厚度的核靶的制备程序，成功地将^237Np以2－700μg/cm^2沉积下来。     

核靶厚度和均匀性测量

文章系统地介绍了核靶厚度和均匀性的测量方法,这些方法都有各自的特点:石英微量天平的灵敏度高(0.04μg/cm~2);等效空气α粒子测厚仪的测量范围宽;吸光光度法测量快速而背散射法既能测量核靶厚度又能分析靶膜的杂质。结合以上方法,能测量不同元素和不同种类核靶的厚度和均匀性。     

^54Mn核的高自旋态研究

本工作研究^54Mn核的高自旋态。实验在中国原子能科学研究院的HI-13串列加速器上完成的，通过重离子熔合蒸发反应^12C＋^48Ti布居^54Mn核的高自旋态。实验中，^48Ti靶的厚度为1.5mg／cm^2，铅衬底为厚度20mg／cm^2。为了测量激发函数，束流能量分别选择从55-85MeV之间的7个能量点。     

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。     

核靶厚度和均匀性测量

本文系统地介绍了核靶厚度和均匀性的测量方法,包括天平称重法、石英晶体测厚法,等效空气α粒子能量损失法,吸光光度法和离子背散射法。这些方法都有各自的特点:石英微量天平的灵敏度高(0.04μg/cm~2);等效空气α粒子测厚仪的测量范围宽;吸光光度法测量快速而背散射法既能测量核靶厚度又能分析靶膜的杂质。将这几种方法结合起来,就能测量不同元素和不同种类核靶的厚度和均匀性。     

核靶厚度和均匀性测量

本文系统地介绍了核靶厚度和均匀性的测量方法,包括天平称重法、石英晶体测厚法,等效空气α粒子能量损失法,吸光光度法和离子背散射法。这些方法都有各自的特点:石英微量天平的灵敏度高(0.04μg/cm~2);等效空气α粒子测厚仪的测量范围宽;吸光光度法测量快速而背散射法既能测量核靶厚度又能分析靶膜的杂质。将这几种方法结合起来,就能测量不同元素和不同种类核靶的厚度和均匀性。     

Be靶制备技术研究

介绍了Be靶制备的电阻加热法、滚轧法、静电振动法、离心沉淀法、聚集束溅射法等。结果显示：电阻加热和滚轧制备自支撑Be靶的厚度范围分别为20－970μg/cm^2和3．8－20μm。     

同位素铁靶制备技术

介绍了同位素铁靶的制备技术，包括氧化铁的还原、铁粉的熔化和铁靶的制备。采用聚焦束溅射和滚轧制备技术能获得自支撑^56Fe靶的最小厚度分别为50和360μm/cm^2。     

27 ^178Os的高自旋态寿命测量

实验工作于2004年9月在HI-13串列加速器上完成。通过重离子熔合蒸发反应^29Si＋^154Sm布局^178Os核的高自旋态。实验中^154Sm靶的厚度为1．4mg／cm^2，衬底采用厚度为20mg／cm^2的铅衬，束流能量为155MeV。     

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.