精确测量波荡器磁场的伸展线磁测系统

为了准确测量上海同步辐射装置(SSRF)上的波荡器,研制了一套一次场积分、二次场积分和多极场分量的磁场测量系统,该系统具有测量快速、准确、不受空间限制等特点,尤其在测量小间隙波荡器方面具有Flipping coil不可替代的优势.结果显示,该系统的一次场积分测量精度好于1.2 Gs·cm,二次场积分测量精度好于150 Gs·cm2.     

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。     

PSD位置测量系统在波荡器磁场测量中的应用

位置敏感探测器(Position Sensitive Detector,PSD)是一种基于横向光电效应(x和y方向)的光电位置敏感器件,可直接探测到入射光斑的能量中心位置,在波荡器磁测中可用于获得霍尔探头测量过程中的横向位置变化。为了在狭小或封闭空间内实现对波荡器(尤其是真空内波荡器)磁场进行高精度的测量,我们设计并搭建了测试系统,对导轨直线度(x和y方向)进行了测量。实验结果表明,该位置测量系统具有5μm的测量精度,可以满足霍尔探头在波荡器磁测过程中的位置精度要求。     

SHINE超导波荡器磁场点测量霍尔探头位置标定

正在建设的上海硬X射线自由电子激光装置（Shanghai HIgh repetitioN rate XFEL and Extreme light facility,SHINE）将利用40台周期长度为16 mm、磁长度为4 m、净气隙高度为4 mm的真空内超导波荡器,以产生垂直线极化的自由电子激光。霍尔探头磁场测量是目前测量波荡器场图最可靠的测量方法之一,而霍尔探头灵敏中心的定位精度是影响磁场测量精度的主要因素之一。本文介绍了这些超导波荡器的磁场点测量系统,以及霍尔探头灵敏中心的高精度位置标定。通过翻转安装有霍尔探头与角锥棱镜的磁测滑车,可分别标定霍尔探头灵敏中心以及角锥棱镜顶点和磁测滑车翻转轴的横向间距,从而获得霍尔探头灵敏中心彼此之间的横向距离,以及霍尔探头灵敏中心与角锥棱镜顶点之间的横向距离。该方法的标定精度好于±10μm,能满足该超导波荡器磁场测量的要求。     

用于质子治疗的Kicker磁铁动态磁场测量

华中科技大学在研的质子治疗装置(Huazhong University of Science and Technology Proton Therapy Facility,HUST-PTF)中,一套位于降能器上游的Kicker磁铁被用于点扫描过程及治疗安全的快速束流开启/关断。为测量该Kicker磁铁的积分场均匀度及磁场动态特性,设计并研制了一套基于电磁感应法的Kicker磁铁测磁系统。测磁系统分别采用长线圈和印制电路板(Printed Circuit Boards,PCB)线圈两种方法获取感应电压,通过模拟/数字积分器对感应电压进行积分处理。经过实验对比,采用几何精度更高的PCB线圈和受零漂影响较小的模拟积分器作为最终方案进行测试;磁场上升/下降时间小于100μs,积分场大于0.025 2 T·m,均匀度好于1%,均匀度最大标准差0.006%,测磁系统整体误差小于0.1%,表明Kicker磁铁及其测磁系统均满足设计指标。     

SSRF波荡器EPU148动力学积分场效应磁场垫补

阐述了减少"APPLE(Advanced Planar Polarized Light Emitter)-II"型可变椭圆极化波荡器动力学积分场效应的"L-Shimming"垫补方法的原理。优化设计了上海光源"梦之线"光束线站波荡器EPU148磁场垫补方案,磁场实际测量结果和模拟计算结果基本一致,误差小于最大垫补量的10%,垫补后动力学积分场效应对束流的影响减少一个数量级。机器研究结果显示,波荡器EPU148所有工作磁气隙和所有工作相位下引起的工作点漂移小于0.001,对束流注入效率基本没有影响,证明了其动力学积分场效应垫补是成功的。     

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。     

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。     

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。     

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。     

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.     

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.     

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。     

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.