光电耦合器的单粒子瞬态脉冲效应研究

利用脉冲激光模拟单粒子效应实验装置研究光电耦合器HCPL-5231和HP6N134的单粒子瞬态脉冲(SET)效应.实验获得了相关器件的单粒子瞬态脉冲波形参数与等效LET的关系,并甄别出器件SET效应的敏感位置,初步分析了SET效应产生的机理.利用脉冲激光测试了光电耦合器的SET宽度与等效LET的关系,并尝试测试了两种光电耦合器的SET效应的截面,其中,HCPL-5231的实验结果与其他文献利用重离子加速器得到的数据符合较好,验证了脉冲激光测试器件单粒子效应的有效性.     

重离子和脉冲激光模拟单粒子翻转阈值等效性研究

根据重离子和脉冲激发诱发单粒子翻转机理,分析了重离子和脉冲激光模拟单粒子翻转阈值（激光能量与重离子线性能量转移（LET））等效方法，得出脉冲激光与重离子单粒子翻转阈值等效计算公式。应用实验室的激光模拟单粒子效应试验系统，开展了几种器件和集成电路的单粒子翻转实验研究。利用获得的计算公式计算激光等效LET阈值，并与国内外重离子实测数据进行比较。结果表明，脉冲激光能量等效LET阈值与重离子试验LET阈值较为一致。     

单粒子效应辐射模拟实验研究进展

应用质子直线加速器进行了静态随机存取存储器(SRAM)的单粒子效应模拟实验研究.采用金箔散射法降低质子束流,研制了弱流质子束测量系统,测量散射后的质子束流,实验测得SRAM质子单粒子翻转截面为10-14 cm2/bit量级.利用重离子加速器和锎源进行了SRAM的单粒子效应实验.研究其单粒子翻转截面与重离子线性能量传输(LET)值的关系,得到了单粒子翻转阈值和饱和截面.实验表明252Cf源单粒子翻转截面与串列加速器的重离子单粒子翻转截面一致,说明对于SRAM,可以用252Cf源替代重离子加速器测量单粒子翻转饱和截面.与中国原子能研究院、东北微电子研究所合作开展了国内首次重离子微束单粒子效应实验.建立了大规模集成电路重离子微束单粒子效应实验方法,找到了国产SRAM的单粒子翻转敏感区.应用14MeV强流中子发生器进行了SRAM单粒子效应实验,测得了64K位至4M位SRAM器件14MeV中子单粒子翻转截面.用α源进行SRAM单粒子效应辐照实验,模拟封装材料中的232Th和238U杂质发射出的α粒子导致的单粒子翻转.测量α粒子射入SRAM导致的单粒子翻转错误数,计算单粒子翻转截面和失效率,比较三种器件的抗单粒子翻转能力,为器件的选型提供依据.并开展了路由器的α粒子辐照实验,复演了路由器在自然环境中的出错情况,为路由器的设计改进提供了依据.     

IDT6116单粒子敏感性评估试验技术研究

为评估IDT6116SRAM单粒子敏感性,采用地面试验方法和地面试验系统,利用脉冲激光、重离子和²⁵²Cf源3种不同的地面模拟源,对IDT6116SRAM器件进行单粒子敏感性试验研究,并对3种不同的模拟源的试验结果进行等效性分析比较,同时进行总剂量效应对单粒子效应影响的试验研究。研究结果表明：IDT6116SRAM抗单粒子翻转和锁定的能力较强;接受一定辐照剂量后的试验样品对单粒子翻转更加敏感,且翻转阈值略有降低,翻转截面略有增大。     

反熔丝型现场可编程门阵列单粒子锁定实验研究

利用单粒子效应脉冲激光和锎源模拟试验系统,对反熔丝型A42MX36现场可编程门阵列进行了单粒子锁定敏感性评估试验.脉冲激光试验确定了单粒子锁定脉冲激光阈值能量及其等效重离子LET、锁定电流等敏感参数;锎源模拟试验确定了单粒子锁定截面.对试验中出现的由单粒子绝缘击穿和单粒子伪锁定引起的电流跃变现象进行了讨论和分析.     

脉冲激光和重离子辐照FPGA产生的多位翻转效应的比较

以SRAM型FPGA为试验对象,研究脉冲激光模拟重离子产生单粒子多位翻转效应的可行性。FPGA的多位翻转依据其物理位置关系的不同分为3种类型:同帧同字节、同帧相邻字节和相邻帧。针对Virtex-ⅡFPGA分别进行脉冲激光与重离子的单粒子多位翻转效应的测试,对比脉冲激光和重离子在Virtex-ⅡFPGA产生多位翻转的类型、多位翻转的物理位置关系。结果表明,脉冲激光触发的Virtex-ⅡFPGA的多位翻转物理位置关系与重离子相同,对比脉冲激光与重离子的饱和翻转截面发现,应用脉冲激光和重离子得到的Virtex-Ⅱ饱和翻转截面基本一致,表明脉冲激光可模拟重离子研究Virtex-ⅡFPGA的多位翻转效应。     

电流型PWM控制器单粒子脉冲瞬态效应的试验研究

采用理论分析与试验对比的方式,对脉宽调制(Pulse Width Modulation,PWM)控制器的脉冲激光模拟单粒子瞬态(Single Event Transient,SET)效应的等效性进行研究。对常用的电流型PWM控制器采用脉冲激光进行照射试验,通过改变激光能量得到不同条件下的试验数据,并与重离子照射条件下的试验数据进行对比。试验结果证实线状能量传递值LET(Linear Energy Transfer)=65.2 Me V·cm2·mg-1的868.3 Me V Xe重离子与波长1.064μm、能量为1–2 n J的脉冲激光产生的SET效应最为接近。试验结果为采用脉冲激光对同类型PWM控制器进行模拟SET试验提供了数据支撑。     

脉冲激光模拟单粒子效应研究

脉冲激光在集成电路和器件单粒子效应(Single Event Effect,SEE)研究中有着广泛的应用。与重离子源相比,通过脉冲激光诱发SEE更容易获得空间信息和时间信息。本文介绍激光诱发SEE的产生机理、模拟试验设置以及线性能量传输(Linear Energy Transfer,LET)算法,通过皮秒激光诱发单光子与飞秒激光诱发双光子的模拟试验,对SEE现象发生时电压响应与能量的关系进行分析,验证了脉冲激光在SEE研究中的有效性和可行性。     

SRAM单粒子效应监测平台的设计

SRAM单粒子效应监测平台用于兰州重离子加速器(HIRFL)辐照终端开展单粒子效应实验,采用"承载子板-主控制板-上位机"结构.简要分析了SRAM单粒子效应产生机理,详细描述了该平台的硬件系统、软件系统和性能指标.重离子辐照实验中,该平台多次检测到IDT71256发生单粒子翻转和单粒子闩锁,实验结果与理论分析的结论基本一致.     

静态随机存取存储器重离子单粒子翻转效应实验研究

应用重离子加速器和 2 52 Cf源进行单粒子翻转效应实验 ,测量得到 IDT系列和 HM系列静态随机存取存储器的单粒子翻转重离子 L ET阈值为 4～ 8Me V· cm2 /mg,单粒子翻转饱和截面为 10 -7cm2 · bit-1量级 ,位单粒子翻转截面随集成度的提高而减小。实验结果表明 ,可以用 2 52 Cf源替代重离子加速器测量静态随机存取存储器的单粒子翻转饱和截面     

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.