CSNS电源磁测时序控制系统

电源磁测时序控制系统能够提供磁铁在运行过程中电源控制设备和磁铁测量设备所需要的时序触发信号和同步时钟信号,该系统的准确性和稳定性对于整个磁测显得极为重要。论文介绍了基于Xilinx系列FPGA硬件电路设计、电光-光电转换电路的设计、串口通信驱动模块和LabVIEW-EP-ICS人机控制界面的实现。通过联机测试结果表明,该系统满足了电源磁测对时序控制系统的要求。     

线扫描探测器位移的测量

介绍了基于光学编码的线位移测量系统.系统由位移编码、光学成像和位移读出三个部分组成,位移读出包括光电转换器件(线阵CCD)及其外围电路(CCD驱动电路)、二级放大电路、巴特沃斯二阶低通滤波电路和二值化电路.介绍了编码方式,给出了各个电路的实验信号波形,给出了系统的线性实验测试结果,实验结果令人满意.     

基于CPLD的CCD通用驱动电路设计方法

建立CCD通用测试平台有助于系统研究各类CCD器件的辐射效应及损伤机理。探讨了一种基于CPLD的线阵CCD通用驱动电路设计方法与实现途径。利用MAX-PL USII开发系统,选用MAX7000S系列CPLD芯片,设计实现了核心驱动主控制器,用于读取外部存储器驱动文件,设置相关参数寄存器,并产生符合参数要求的驱动时序脉冲。在此方法的基础上,完成了基本驱动模块电路的设计。基本驱动模块电路输出波形的测试结果表明,这种设计方法是完全可行的。     

LHAASO水切伦科夫探测器阵列时钟原型系统

介绍了LHAASO WCDA读出电子学时钟原型系统的设计,分析了该时钟系统的设计原理,介绍了测试方法和测试结果.该原型系统基于精简的White Rabbit Project原理设计,主要包括时钟源插件、时钟发送插件和时钟接收模块3部分.对该原型系统的测试结果表明,时钟接收模块上两时钟通道之间的时钟偏差可以调整到＜80ps,时钟抖动＜40 ps,可满足LHAASO WCDA读出电子学设计需求.     

基于FPGA的CCD驱动模块设计

本文针对天文观测项目中导星的需求,使用全帧型的CCD探测器KAF-3200,完成了导星CCD相机的驱动模块设计。在介绍CCD芯片KAF-3200的基础上,通过使用FPGA和超低噪声的LDO实现了CCD芯片的时序电路和偏压电路,并通过示波器、ADC采样等方法对该设计进行了多次测试。测试表明该设计有着高速、低噪声、低功耗的优点,满足设计需求,并且为CCD的驱动设计提供了一种新的思路。     

CCD光谱仪的控制系统及数据处理

本文介绍了CCD光谱仪的控制系统及数据处理方法。为了实现光谱测量的自动化,设计了驱动电路控制和计算机控制系统。编制的光谱软件,在对弱谱信号进行处理,奇偶差异信号修正以及光谱灵敏度的补偿后,大大提高了测量精度。     

PEM系统中可控时钟电路设计的优化

介绍了为乳腺专用正电子发射断层扫描仪PEM(Positron Emission Mammography)电子学数据获取(Data Acquisition,DAQ)系统提供稳定、可靠、抗干扰的高精度同步时钟的电路,它采用了基于单片机和高精度时钟产生芯片的电路设计方法,可以得到多路可控时钟信号.设计中采用差分传输,大大降低...     

TOF测量系统读出电子学时钟插件设计

介绍了中国科学院近代物理研究所反应显微成像谱仪和重离子加速器冷却储存环内靶实验中,测量粒子飞行时间读出电子学的时钟插件。两个时钟插件分别集成于3UPXI插件和6UPXI插件上,利用高精度的时钟源和时钟扇出芯片为飞行时间读出电子学系统提供高精度的系统时钟,其抖动分别小于11ps(RMS)和12ps(RMS),满足设计要求。     

高分辨率X射线探测器读出电子学系统的研制及性能测试

本文针对光锥耦合X射线探测器低噪声的设计要求,研制了一套读出电子学系统,该系统包括模拟驱动电路、前端处理电路及基于现场可编程门阵列(FPGA)的数字信号处理电路。利用X射线成像平台,对研发的探测器进行了性能测试。探测器系统绝对增益为0.168 6DN/e-,线性工作范围为0~154μGy。制冷温度为-20℃时,暗电流噪声为0.037e-/(pixel·s),读出噪声为10.9e-。探测器的本征空间分辨率达16lp/mm。测试结果表明,研制的读出电子学系统能满足高分辨率X射线探测器对低噪声特性的需求。     

基于小型无人机的航磁测量系统研发及试验应用

高精度磁力仪是观测地磁场的基本仪器,也是开展高精度磁法测量的核心装备,广泛应用于放射性矿产勘查、多金属矿产勘查以及基础地质调查等领域。为实现在无人机平台上搭载高精度磁力仪开展航空磁测,满足铀资源及多金属等综合矿产勘查的需求,提高空白区和低工作程度区铀资源勘查效率,提出了一种基于FPGA芯片和STM32单片机的高精度磁数据采集系统设计方案,突破了高精度测频和数据采集系统小型化等关键技术,实现了设备小型化和低功耗。通过设计整形电路和FPGA内部基于多通道时间内插法的测频算法,实现了拉莫尔频率的高精度测量,进而得到了高精度的磁场数据;通过设计信号分压电路和24位A/D转换电路实现了磁通门三分量数据的高精度采集。基于STM32单片机实现对磁总场、三分量及辅助测量数据的采集和存储。经测试,该数据采集系统可实现15 000～105 000 nT磁总场数据和-100 000～100 000 nT三分量数据的采集。设计了小型集成化的磁数据采集系统机箱,对数据采集板、电源板和数据接口进行了系统集成,该系统和国外商业化产品相比,体积减小了45%,重量减小了71%,功耗降低了51%。在黑龙江某地区开展了试验...     

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.     

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)

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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.