BH3105型高灵敏中子剂量当量仪

考虑到在传统的“吸收筛”设计原理框架内难以设计成高灵敏度中子剂量当量测量仪,研制了一种基于全新的中子剂量生物等效调整原理——“吸收棒”法的BH3105高灵敏度中子剂量当量仪。该仪器的灵敏度达10cps/(μSv·h~(-1)),比国外同类仪器高18～40倍,比国产FJ342型中子雷姆仪高约10~4倍。其量程范围为0.1～1Sv/h,比同类仪器扩展1～2个     

裂变径迹个人中子剂量计

本文叙述了~(285)U-涤纶和~(282)Th-涤纶两种裂变径迹中子剂量计,配用一台火花计数器,实现了径迹的自动计数。计算了利用不同的(n,f)反应探测中子注量和剂量的灵敏度,以及~(282)Th探测器的拉德响应系数。火花计数的线性区域可达到(0.3～1.5)×10~3火花/厘米~2,相应的可测剂量范围约为20毫雷姆—60雷姆。     

可携式中子剂量当量率仪

本文介绍NH1型可携式中子剂量当量率仪的结构和性能。该剂量仪由包有聚乙烯慢化体和硼塑料层的球形~3He计数管和电子学系统组成,适于热能—15MeV能区的中子剂量当量率的测量。剂量当量率测量范围在0.1—10~4μSv/h之间;在热能附近能区和0.3—5MeV能区,剂量当量率响应随能量的变化在±30％以内,对于能量为1.15MeV的中子,响应值约为0.56cps/μSv·h~(-1)。该剂量仪具有模拟和数字显示,重量为7kg。在改换量的名称并对能响作适当修正的条件下,NH1型中子剂量当量率仪可用于中子周围剂量当量率的测量。     

BH3105型高灵敏中子剂量当量仪

考虑到在传统的“吸收筛”设计原理框架内难以设计成高灵敏度中子剂量当量测量仪,研制了一种基于全新的中子剂量生物等效调整原理——“吸收棒”法的BH3105高灵敏度中子剂量当量仪。该仪器的灵敏度达10cps/(μSv·h~(-1)),比国外同类仪器高18～40倍,比国产FJ342型中子雷姆仪高约10~4倍。其量程范围为0.1～1Sv/h,比同类仪器扩展1～2个量级。其它性能,如耐γ性能、能量响应及方向性等,皆达到与超过国外同类产品水平。     

中子等剂量当量探测实验方法研究(英文)

对中子剂量当量仪实现中子生物等效探测的原理进行了研究。讨论了“吸收筛法”与“多探测器法”两种传统的实验方法。在此基础上,提出一种新的实现中子生物等效探测的原理——“吸收棒法”,以期实质性地提高该类仪器的中子灵敏度,克服两种传统方法的缺陷。并基于新原理,研制成功一种新型的中子剂量当量仪。该仪器的中子灵敏度达10cps/(μSv·h~(-1)),比国内外现有的同类仪器指标(0.23～0.56cps/(μSv·h~(-1))),高18至40倍。其它技术指标也皆达到或超过国际上现有的同类产品水平。因而证实了“吸收棒法”实现中子生物等效探测原理的科学性、先进性与实用性。     

~(241)Am-Be源和~(226)Ra-Be源的中子注量-剂量换算系数

在中子剂量仪表刻度和中子剂量计算中经常遇到单位注量中子与比释动能、吸收剂量、剂量当量之间的换算关系。它们之间的数值关系通常称为中子注量-剂量换算系数。在《放射防护规定》中规定职业放射性工作人员最大容许剂量当量为每年5雷姆。同时又对2.5毫雷姆/小时对应的中子通量(中子/厘米~2·秒)进行了规定(见附表1第7栏)。国际辐射防     

测量~(85)Kr的同轴多丝正比计数器的研制

本文介绍一种用同轴多丝正比计数器测量~(85)Kr的装置。装置探测效率为80％,灵敏度为4—10~(-12)Ci/1。它可以把气体样品密封在计数器内测量,亦可在气体流速小于61/min时进行连续测量。一、引言目前国内外测量~(85)Kr的方法很多,如电离室法、G-M计数器和塑料闪烁计数器测量法,其灵敏度范围为10~(-10)—10~(-11)Ci/1。如果把它们直接用于测量环境中的     

福建省环境天然贯穿辐射水平调查

本文报道了福建省环境天然贯穿辐射剂量水平调查的方法和结果。全省以25×25 km 网格均匀布点,共布设网格点173个,各类加密点170个。调查结果表明:(1)原野天然γ辐射剂量率按测点、面积和人口的加权均值分别为9.26、9.23和8.71×10~(-8)Gy·h~(-1);(2)道路天然γ辐射剂量率按点平均为10.64×10~(-8)Gy·h~(-1);(3)建筑物室内天然γ辐射剂量率按测点和人口的加权平均值分别为15.58和15.65×10~(-8)Gy·h~(-1);(4)宇宙射线电离成分所致空气吸收剂量率按测点和人口的加权平均值,室内分别为2.42和2.39×10~(-8)Gy·h~(-1),室外分别为3.03和2.99×10~(-8)Gy·h~(-1);(5)天然贯穿辐射剂量率(不包括中子成分)按测点和人口的加权平均值,室内分别为18.00和18.05×10~(-8)Gy·h~(-1),室外分别为12.29和11.70×10~(-8)Gy·h~(-1);(6)天然γ辐射、宇宙射线和天然贯穿辐射所致福建人均年有效剂量当量分别为0.84、0.22和1.06 mSv,全省集体年有效剂量当量分别为2.31、0.60和2.91×10~(-4)人·Sv。调查中发现“鬼头山”天然γ辐射异常本底区。该区(约2km~2)的原野天然γ辐射剂量率平均值约为40.94×10~(-8)Gy·h~(-1),是全省平均值的4.4倍。     

几种中子雷姆仪剂量特性的测量和比较

本工作对FJ-342、95/0075-1/6及实验用雷姆探头三种中子雷姆仪的剂量特性进行了测量和比较。所涉及的剂量特性包括灵敏度、方向性、能量响应及稳定性。根据灵敏度和本底数据对可探测剂量当量率的下限作了估计。     

CR-39塑料反冲径迹个人中子剂量计

本文叙述了一种用于测量中子剂量的“直接相互作用”型的CR-39塑料反冲径迹个人中子剂量计。该剂量计对~(241)Am-Be源的中子注量灵敏度约为(2.10±0.05)×10~(-4)径迹/n,可探测的中子注量下限约等于2.11×10~5n/cm~3,相应的中子剂量当量为7.81×10~(-5)Sv。总误差估计不超过±20％。     

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.     

Gamma radiation levels in the ambient environment of the QNPP Base

Monitoring results of gamma dose rate level in 1992～2004 in the ambient environment of the Qinshan Nuclear Power Plants(QNPP)Base,the northeast of Zhejiang Province,are reported in this paper.It is shown that the gamma dose rate of five monitoring sites of 2.5 km to QNPP Base is 84～113 nGy/h,with an average of 96 nGy/h in the 13 years.The average value is close to the background level of 93 nGy/h prior to operation of the QNPP Base,and is lower than the monitoring result of 101 nGy/h at the reference site in Hangzhou City.Within 50 km from the QNPP Base,the cumulative dose rate of the thermoluminescent dosimeter(TLD)is 90 nGy/h,which is lower than the back- ground level of 111 nGy/h.