兰州重离子研究装置周围环境中子和γ辐射监测系统

本文主要介绍兰州重离子研究装置(HIRFL)周围环境中子和γ辐射监测系统的组成及其性能、测点的布置和初步的运行情况。该系统设4个本地站,每个站内各有一台中子和γ探测器及数据采集器,能自动连续给出结果。运行结果表明,该系统能够区分加速器运行和“雨雪冲刷”对环境本底造成的变化。     

兰州重离子研究装置周围环境的放射性监测

叙述了对兰州重离子研究装置周围环境中土壤,植物和水中总α,总β放射性的监测情况。给出了测量结果,并进行了初步评价,连续７年的监测表明,ＨＩＲＦＬ周围环境样品的放射性都在本底水平,装置的运行未对环境造成污染。     

兰州重离子加速器工作区域36路剂量监测数据获取系统

介绍兰州重离子加速器工作区域辐射环境的剂量监测数据获取系统，该系统具有３６路数据获取功能，可同时满足１８个监测点的中子、γ数据测量，实现了数据多点采集，自动同时获取和实时在线分析。对数据采集、数据存储、声学报警、剂量安全联锁及数据测量结果等进行了详细介绍。     

兰州重离子研究装置的区域监测和安全系统

木文主要介绍了兰州重离子研究装置(HIRFL)的区域监测系统(包括中子和γ探测器及数据采集和处理系统)和辐射安全系统(包括报警系统和安全联锁系统)的设计和性能,以及它们在HIRFL调束中的应用。     

兰州重离子研究装置（HIRFL）的辐射防护

本文介绍了兰州重离子研究装置（ＨＩＲＦＬ）的辐射防护概况。分五个部分：（１）装置概况；（２）辐射发射率；（３）辐射屏蔽；（４）感生放射性及其对环境的影响；（５）区域监测及安全系统。     

医用质子/重离子加速器辐射屏蔽设计概述

近年来我国医用质子/重离子加速器治癌产业开始飞速发展。粒子加速器运行时会产生次级辐射从而危及环境、公众及工作人员的辐射安全,可靠的辐射屏蔽设计是装置运行时辐射安全的必要保障。本文简要分析了医用质子/重离子加速器辐射屏蔽设计的一般考虑因素;介绍了几种常用的屏蔽计算方法并给出了计算实例。本文的研究内容对未来将要建造的医用质子/重离子加速器的辐射屏蔽设计具有一定的参考意义。     

山西省城市放射性废物库周围辐射环境监测(2016—2019)

山西省核技术利用项目产生的放射性固体废物(源)暂存于山西省城市放射性废物库。2016—2019年,废物库废旧放射源存量增加近千枚。2016—2019年,对废物库库区周围辐射环境(包括:库区周围γ辐射剂量率,库区α、β表面污染水平,气溶胶总β水平,库区及周围水中总α、总β水平,库区及周围居民点土壤中γ核素水平等项目)的监测结果显示,废物库周边辐射水平处于天然辐射水平范围内,未见可察觉的改变。     

EAST托卡马克装置的核辐射监测系统

EAST(Experimental Advanced Superconducting Tokamak)现阶段D-D运行产生2.45 Me V聚变中子及次级核反应γ射线,为了解EAST运行期间辐射场的分布及强度,确保运行期间人员及环境的核辐射安全。针对EAST运行期间装置大厅内部存在较强的中子、伽马瞬变辐射场的特征,结合环境低本底辐射监测的需要,采用宽动态范围、快时间响应的场所辐射监测探测器,与高灵敏度、稳定性好的环境辐射监测探测器相结合的方式,围绕EAST装置布置13个辐射监测点,每点分别安装一台中子、伽马监测器。采用自行编写的Lab VIEW辐射监测软件进行数据采集,组建了一套EAST托卡马克装置的中子、伽马辐射剂量监测系统。该系统在2015年春季EAST实验中连续稳定运行了三个月,可靠性较高,获取了大量实验数据。监测系统满足EAST核辐射监测的要求,同时为后续开展聚变堆辐射安全与防护研究提供实验平台。     

兰州重离子研究装置的辐射监测系统

介绍了兰州重离子研究装置工作场所辐射监测系统的组成及性能,通过多年的现场使用,具有良好的稳定性和抗干扰能力,可以满足大型加速器或其他核装置的现场辐射剂量监测的需要。     

磁约束聚变装置辐射监测系统概况

采用氘、氚燃料的核聚变反应会产生大量的中子、γ射线及活化产物等,对人员和环境的辐射安全产生影响。为了减小电离辐射带来的影响,需要准确掌握聚变装置核辐射场强度的时间与空间分布信息。世界上已建设的磁约束聚变装置,均根据其自身运行工况特点,建立了完整的核辐射监测系统来应对电离辐射带来的潜在影响。通过对磁约束聚变装置运行及维护期间辐射剂量的监测,获得实验场所与外围环境的电离辐射和放射性核素数据,为辐射安全防护管理提供数据支撑。基于对国内外磁约束聚变装置辐射监测系统的调研,本文归纳了此类装置主要的电离辐射源项及监测系统架构,进而介绍了磁约束聚变中子与γ辐射剂量的测量方法及常用探测器。最后综述了国内外核聚变装置辐射监测系统的研究状况,展望了未来核辐射监测系统的发展趋势与目标。     

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.