高计数率气体探测器读出电子学原型机研制

研制一套可用于高计数率气体探测器的读出电子学原型机系统,包括前端板、数据采集板和上位机。前端板采用一款先进的前端读出专用集成电路(ASIC)芯片实现对探测器信号的测量和模数转换;数据采集板利用现场可编程门阵列（FPGA）实现对数据的分析、处理和传输;上位机实现控制指令发送、PC端数据接收及存储等。在22~99 fC的输入范围内,原型机各通道积分非线性均好于024%;联合探测器使用55Fe放射源测试,结果好于相同条件下的商用电子学。可满足20 kHz计数率下GEM TPC探测器的读出需求。     

BESⅢ Muon鉴别器前端电子学读出系统

本文介绍了BESSⅢ Muon前端电子学读出系统的结构,详细说明了依据菊花链方式的前端板和基于USB的读出板的设计和实现方法.该系统中较多地采用了FPGA技术,极大地降低了系统的复杂程度和建造成本.文章最后介绍了系统的自检方式,并给出了该系统在北京高能物理研究所谱仪大厅内的宇宙线测试结果,论证了系统的可靠性.     

基于ASIC的Si-PIN探测器读出系统

为了实现大面积多通道Si-Pin探测器前端电子学的高度集成,设计了一种基于ASIC技术的电子学读出系统.文章主要介绍了该ASIC芯片的特点以及读出电子学的系统结构和工作原理.我们对电子学系统进行了一些测试,给出了连接Si-Pin探测器得到的Am-241源的能谱图.     

高密度塑料闪烁体探测器的数据获取系统设计

由中国科学院近代物理研究所承担的塑料闪烁体探测器研究项目,其目标是开展空间粒子探测、重构入射电子轨迹、区分电子和光子、鉴别重离子。为配合该探测器测试工作,设计了一套完备的数据获取电路(DAQ)与上位机软件。DAQ接收4块前端电子学(FEE)板的数据,可完成360路电子学通道的数据读出;接收上位机的控制命令并分发给各FEE;接收探测器的击中信息并产生触发信号;接收FEE的遥测数据并传给上位机。该DAQ与上位机通过USB总线和RS232总线实现实时通信。上位机软件基于LabWindows/CVI软件平台开发,实现对FEE电子学系统的控制、数据读取与保存,以及FEE系统运行状态参数信息的实时显示。该数据获取系统电路结构紧凑、功能完善,上位机软件具有良好的人机交互界面。经现场实际运行,DAQ与上位机软件满足设计要求,目前已成功应用于塑料闪烁体探测器读出电子学测试系统。     

硅条探测器前端ASIC芯片测试系统电路设计

介绍一种前端读出专用集成电路(ASIC,Application-Specific Integrated Circuit)芯片性能测试系统的电路设计与实现.该ASIC芯片可用于构成硅微条探测器、硅条、Si(Li)和CsI探测器的前端读出电子学系统.本文详细描述了测试系统的构成,主要电路设计,系统应用以及部分测试结果,并简要介绍了被测ASIC芯片的电路结构.     

大亚湾RPC探测器电子学读出传输板设计

主要介绍了大亚湾反应堆中微子振荡实验RPC电子学系统中读出传输板的设计.文章内容包括板子的硬件设计,FPGA的主要逻辑设计以及工程原理样机的建立.目前该读出传输板已经用于RPC电子学系统的测试.     

大亚湾实验RPC探测器信号读出前端板的高精度甄别阈的设计

介绍了大亚湾中微子振荡实验中阻性板探测器RPC(Resistive Plate Chamber)读出电子学前端板FEC(Front-End-Card)上高精度甄别阈电路的设计原理和相关测试。该电路具有高精度、低的甄别阈值设置能力、好的一致性保障等特点。在介绍该电路设计原理的同时,也给出了相应的检测实验和结果。     

μ子鉴别器电子学系统数据读出插件

在我们所设计的北京谱仪第三代（BESIII）μ子鉴别器电子学系统原型机中,前端电路板（FEC）将采集的阻性板探测器（RPC）信号经由30m长电缆传送到远端的数据读出插件中。该插件实现数据接收、数据压缩、发送控制命令、配置和测试FEC、驱动信号,以及通过USB接口与上位机交互等功能。     

大亚湾中微子实验波形数据获取软件设计

介绍了大亚湾中微子实验波形数据读出和数据压缩算法的数据获取软件设计。该软件是以大亚湾中微子实验数据获取系统为基础,在不影响现有电子学系统正常取数的前提下,针对一号实验厅新增的一套前端电子学系统实现波形数据的网络读出、检查、组装、压缩和存盘等功能的软件系统。文中详细说明了波形数据的读出流程以及不同数据压缩方法的实现,并给出了软件的长期稳定性测试结果。     

基于wxWidgets的闪烁晶体阵列探测器数据获取软件设计

介绍了一种用于闪烁晶体阵列探测器读出电子学的数据获取与分析读出软件。软件基于wx Widgets平台开发,采用了模块化设计,上位机通过USB总线与电子学硬件部分通信。软件系统包括命令行接口模块、数据采集模块、参数测量模块、时间和幅度校准模块以及实时显示模块。将软件应用于闪烁晶体阵列探测器系统的调试与测试,结果表明:软件可方便地应用于其它探测器前端电子学的读出系统中,具有广泛的应用前景。     

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。     

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.     

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.