上海软X射线装置中纯永磁移相器的积分场垫补

X射线自由电子激光(Free-electron Laser,FEL)达到饱和功率输出时所需要的波荡器总长度为数十米甚至上百米,目前国内外研制的波荡器只能分段加工,且每段长度一般在5 m以内。为了保证两相邻波荡器间辐射光的相位相互匹配,通用的设计是在相邻波荡器之间增加移相器。移相器的加入不应对电子束流产生影响,其产生的磁场沿束流方向的一二次积分必须达到技术要求。由于移相器较短,二次积分较小,可不予考虑。在不考虑永磁块非线性的基础上,导出了纯永磁移相器的磁场一次积分以及调整移相器中某些磁化块的高度和倾斜角度产生的磁场一次积分变化量的解析表达式。利用这种方法对上海软X射线自由电子激光装置中的5台移相器做积分场垫补,使得每台移相器的磁场一次积分在好场区内都小于20 Gs·cm,满足工程设计要求。     

多目标遗传算法在波荡器垫补中的应用

波荡器性能一般有多个指标要求,而这些指标往往是相互冲突的,因此在磁场垫补时难以对垫补量进行精确推算,导致磁场垫补耗时和低效。为解决该问题,本文将多目标遗传算法应用于波荡器磁场垫补量推算,并对波荡器U38-S磁场进行了垫补。根据波荡器磁场垫补结构建立了计算模型,并阐述了计算模型中的主要问题,给出了U38-S磁场的垫补过程。经过3次磁场垫补,U38-S的轨迹中心偏差、相位误差和峰峰值误差分别减小到0.15 mm、1°和0.49%。由于遗传算法本身具有较强的可扩展性,本文所用方法也可应用于其他类型波荡器的磁场垫补。     

多目标遗传算法在波荡器垫补中的应用

波荡器性能一般有多个指标要求,而这些指标往往是相互冲突的,因此在磁场垫补时难以对垫补量进行精确推算,导致磁场垫补耗时和低效。为解决该问题,本文将多目标遗传算法应用于波荡器磁场垫补量推算,并对波荡器U38-S磁场进行了垫补。根据波荡器磁场垫补结构建立了计算模型,并阐述了计算模型中的主要问题,给出了U38-S磁场的垫补过程。经过3次磁场垫补,U38-S的轨迹中心偏差、相位误差和峰峰值误差分别减小到0.15 mm、1°和0.49%。由于遗传算法本身具有较强的可扩展性,本文所用方法也可应用于其他类型波荡器的磁场垫补。     

可变椭圆极化波荡器EPU10.0的传动控制

可变椭圆极化波荡器EPU10.0是一种可产生多种极化模式相干太赫兹辐射的波荡器。EPU10.0的主要特点是波荡器内的磁块分上下各两排，上下气隙固定，一对对角线永磁块排列固定，另一对可独立做纵向移动，移动重复定位精度小于0.01mm。对该波荡器的磁测结果显示：在水平线极化和圆极化模式下，磁场的两个横向分量的一、二积分分别为0.012T•cm和0.7T•cm²，达到了设计指标。     

上海光源真空内波荡器积分场垫补中模拟退火算法的应用

上海光源真空内波荡器(IVU-25)系我国第一台真空内波荡器,由我所设计和研制。该波荡器采用混合型磁体结构,共80个磁周期,周期长度25mm,最小工作磁间隙7mm,最大峰值磁场强度0.94T。波荡器磁块的剩磁离散性及安装机械公差等因素会引起积分场误差从而影响储存环工作状态。在波荡器积分场多极分量垫补过程中,我们用模拟退火算法优化一次积分场分布来垫补多极分量,结果表明积分场多极分量均达到设计指标。     

脉冲线测量波荡器磁场的研究

介绍脉冲线测量波荡器磁场一、二次积分分布的原理和一套较高精度的脉冲线测量系统的研制，分析了传感器、实验环境、线的张力和波的反射性等因素对测量精度的影响。该系统对5周期波荡器模型的磁场测量结果与高精度Hall探头测量值作了比较，结果满意。     

紧凑型回旋加速器中一种等时性磁场垫补算法

结合中国原子能科学研究院100 MeV回旋加速器中心区实验台架主磁铁镶条的垫补,发展了一种改进的多元线性回归磁场垫补算法.基于磁场测量系统实测的实验台架中心平面上的磁场分布以及有限元软件模拟数值计算的磁场,实现了这种改进的多元线性回归磁场垫补算法.该算法可适用于紧凑型回旋加速器中等时性磁场的垫补,以使所垫补的磁场满足回旋加速器束流动力学设计的要求.     

一种使用磁场相机的混合波荡器磁化块排序方法

描述了一种考虑了磁化块局部磁矩不一致性的混合型波荡器磁化块初始安装排序方法。该方法基于独特设计的磁场相机,该相机用来扫描测量波荡器磁化块南北极附近的场图。排序优化流程为:由磁场相机所测得磁化块南北极附近场图推算出该磁化块内的局部磁矩误差分布,通过三维模拟计算得出含有局部磁矩误差的磁化块安装在波荡器梁上后对波荡器磁场的影响,最终依据这些影响数据对磁化块进行排序。该方法在一台短周期混合型波荡器样段上进行测试,所得结果表明在优化后的半周期积分场误差离散性明显小于未优化的情况,从而确认该方法是有效的。     

基于拉伸线法的振荡器型THz-FEL波荡器积分场测量

为精确、快速测量波荡器磁场积分,研制了一套基于拉伸线法的测磁系统。该系统采用Agilent 3458A八位半数字万用表实现微电压信号采集,使用Kohzu高精度位移平台实现拉伸线的精确同步移动,测量软件平台采用Lab VIEW实现。使用测磁系统在一台7周期混合永磁型波荡器样机上进行了测量实验,结果同霍尔探头点测吻合,一次积分和二次积分的重复测量精度分别优于2.5?10?6 T·m和2.5?10?6 T·m2。该系统将用于华中科技大学在研的一套紧凑型THz波段自由电子激光装置中波荡器磁场测量。     

波荡器磁场误差对其自发辐射的影响模拟研究

波荡器由多个单磁块组成,磁块不可避免的剩磁离散性和尺寸离散性是引起波荡器磁场误差的根本原因。波荡器磁场误差将影响波荡器自发辐射谱的质量。本文给出一种新的单磁块磁场、波荡器磁场及自发辐射的模拟方法,从单磁块磁场模拟人手,使用正态分布随机数发生器产生多组不同剩磁或者不同尺寸的单磁块,再由这种方式产生的单磁块组成波荡器,然后计算自发辐射,从而研究波荡器磁场误差对自发辐射的影响。     

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.     

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。     

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.     

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.     

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.     

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.     

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.