掺入Dy和Mn的MgSO4磷光体的热释光发光光谱

用光学多道分析器和微机控制线性升温法研究了MgSO4:Dy和MgSO4:Dy,Mn热释光材料的发光光谱,测定不同温度和波长的发光光谱,得到了热释光三维光谱图。观察到MgSO4掺入稀土元素Dy的两个发光谱带为480nm和580nm,每个光谱带有多个发光峰。与掺入Dy的CaSO4的三维发光谱相比较,掺入稀土元素Dy的热释光材料的发光谱带的波长主要取决于掺入Dy^3 的能级间的跃迁。MgSO4同时掺入Dy和Mn后,480nm发光谱带受到很大的抑制,所有发光峰的发光效应显著减小;波长为580nm谱带的多个发光峰中,温度低于300℃的发光峰的发光效率显著减小,在380℃附近的发光峰的发光强度最大。这说明掺入Mn杂质后,不同深度的陷阱的相对分布发生了变化。     

掺Dy与Mn的硼酸镁热释光发光谱

本文制备了掺Dy和Mn的MgB4O7的磷光体,并测量其热释光发光谱。测量结果表明,MgB4O7:Mn的热释光发光峰位于180℃和300℃左右,其发光波长分布较宽,中心约为580nm;而MgB4O7:Dy的热释光发光峰位于200℃和350℃,发光波长由Dy3+离子的能级跃迁决定,位于480、580、680和750nm左右。当两者共掺时,只改变Mn的浓度,测量结果发现,随着Mn掺杂浓度的增加,480nm和680nm左右的发光受到抑制,并且低温峰也受到强烈抑制,而580nm的高温峰逐渐增强并且发光谱变宽。     

掺Dy的MgB4O7磷光体的研制及其热释光特性

以碳酸镁和硼酸为原料在高温条件下合成了基质材料MgB4O7并制备了MgB4O7∶Dy磷光体.用RGD-3热释光剂量仪和三维热释光谱仪分别测量了这种磷光体的二维发光曲线和三维发光谱,实验观察到:1)MgB4O7∶Dy磷光体热释光发光峰峰温为220 ℃和380 ℃;2)Dy3 离子的发光波长为480 nm、575 nm和660 nm;3)磷光体220 ℃和380 ℃发光峰的相对强度随高温固相反应温度的升高而变化,但发光峰温和波长基本保持不变.对比MgB4O7∶Dy和MgSO4∶Dy两种热释光材料的三维发光谱,验证了掺入Dy3 离子的热释光材料的发光峰峰温主要由基质材料决定,发光波长则取决于Dy3 离子的能级跃迁的结果.     

MgB4O7:Tb磷光体的研制及其热释光(TL)特性

以碳酸镁和硼酸为原料在高温条件下合成了基质材料MgB4O7并制备了MgB4O7：Tb磷光体。用Risφ／OSL-15-B／C热释光（TL）,光释光（OSL）自动测量仪和TL/OSL三维光谱自动测量仪分别测量了这种磷光体的二维热释光发光曲线和三维热释光发光谱。由MgB4O7：Tb的三维热释光发光谱可看出这种磷光体在230℃、340℃和420℃附近有三个热释光峰,发光谱的波长分别为489nm、548nm、589nm和620nm。此外,不同的高温烧结温度不仅对发光峰的发光强度有很大影响,而且还对。Tb^3＋发光谱形产生影响。当温度高于850℃时Tb^3＋离子发光谱线开始变成了发光谱带。     

MgSO_4:Dy,P和MgSO_4:Dy,P,Cu的热释光剂量学特性

MgSO4 :Dy中掺入适量的P ,热释光发光曲线中两个高温峰显著增强 ,主剂量峰的峰温接近2 83.6℃ ,另一个发光峰的峰温在 35 2 .7℃ ,其热释光效率超过LiF:Mg ,Ti的两倍。MgSO4 :Dy ,P的单个发光峰峰面积对60 Coγ辐射剂量 (0 .1Gy— 2 0kGy)的实验响应曲线用复合作用响应函数拟合 ,得到的非线性特征参数表明 ,两个发光峰的γ辐射剂量响应均为超线性。在MgSO4 :Dy ,P中再掺入微量Cu ,首先抑制峰温在 35 2 .7℃的发光峰 ,随着Cu浓度的增加 ,2 83.6℃的主剂量峰会随之降低 ,此峰的γ辐射剂量响应的超线性随之减小。MgSO4 :Dy ,P ,Cu (0 .1mol% ,0 .5mol% ,0 .0 1mol% )磷光体对γ辐射的剂量响应 (0 .1Gy— 2 0kGy)为亚线性。最引人注目的是MgSO4 :Dy ,P ,Cu(0 .1mol% ,0 .5mol% ,0 .0 0 4mol% )磷光体 ,它具有与MgSO4 :Dy ,P(0 .1mol% ,0 .5mol% )相近的热释光灵敏度 ,并具有最宽的剂量响应线性范围。这种新热释光材料可用于高剂量辐射测量。本文进一步阐明和验证了《复合作用模型》 ,并揭示了热释光材料中杂质和缺陷结构与剂量学特性的相关性。结合热释光三维发光光谱的分析对热释光机制提出一些见解     

MgSO4：Dy,P和MgSO4：Dy,P,Cu的热释光剂量学特性

MgSO4:Dy中掺入适量的P,热释发光光曲线中两个高温峰显著增强,主剂量峰的峰温接近283．6℃,另一个发光峰的峰温在352．7℃,其热释光效率超过LiF:Mg,Ti的两倍,MgSO4:Dy,P的单个发光峰峰面积对^60Coγ辐射剂量（0．1Gy-20kGy)的实验响应曲线用复合作用响应函数拟合,得到的非线性特征参数表明,两个发光峰的γ辐射量响应均为超线性,在MgSO4:Dy,P中再掺入微量Cu,首先抑制峰温在352．7℃的发光峰,随着Cu浓度的增加,283．6℃的主剂量峰会随之降低,此的γ辐射剂量响应的超线性随之减小,MgSO4:Dy,P,Cu(0.1mol%,0.5mol%,0.01mol%)磷光体对γ辐射的剂理响应（0．1Gy-20kGy)为亚线性,最引人注目的是MgSO4:Dy,P,Cu(0.1mol%,0.5mol%,0.004%mol)磷光体,它具有与MgSO4:Dy,P(0.1mol%,0.5mol%)相近的热释光灵敏度,并具有最宽的剂量响应线性范围,这种新热释光材料可用于高剂量辐射测量。本文进一步阐明和验证了《复合作用模型》,并揭示了热释光材料中杂质和缺隐结构与剂量学特性的相关性,结合热释光三维发光光谱的分析对热释光机制提出一些见解。     

掺Dy,Tm和Mn的MgSO4磷光体的热释光发光谱研究

用高温固相法研制了MgSO₄:Dy,MgSO₄:Tm和MgSO₄:Mn热释光材料,并通过将MgSO₄:Dy和MgSO₄:Mn混合,以及MgSO₄:Tm和MgSO₄:Mn混合烧结得到了双掺杂样品MgSO₄:Dy,Mn,MgSO₄:Tm,Mn。分别测量了这两种样品在不同热处理温度下的三维发光谱。实验结果表明热处理温度为700℃时的样品,在测量加热过程中观察到Dy和Mn离子分别发光,但超过800℃后,Mn发光强度逐渐变弱,而Tm、Dy的高温发光峰逐渐变强,其它温度的发光峰受到抑制。这表明热释光材料中形成的缺陷复合体结构与热处理温度相关,随着热处理温度的升高,愈来愈多的Mn离子与稀土离子结合紧密,因此在热释光发光谱中清楚地观察到Mn离子对稀土离子的能量转移和对Tm、Dy低于400℃发光峰进行抑制的发光过程。     

MgSO4:Tm,Mn,P磷光体的研究

通过三掺杂得到MgSO4：Tm,Mn,P，其热释光的两个主要发光峰温分别约为253℃和383℃，发光波长位于365nm、460nm和660nm。比较MgSO4:Tm、MgSO4:Tm,Mn、MgSO4:Tm,P、MgSO4：Tm,Mn,P的发光曲线，讨论了杂质Tm、Mn、P分别产生的作用。采用一般级动力学方程拟合发光曲线，确定出各发光峰的激活能与频率因子。用^60Co γ射线在0.1-20kGy的辐照范围内，测定了它们的热释光剂量响应曲线。用复合作用剂量响应函数拟合实验数据，得到两个发光峰的一次作用因子R分别为0.397(253℃）和0.127(383℃）。     

SrSO4:Eu磷光体的热释光特性

研究了掺杂得到的SrSO4Eu(0.1mol%)的粉末样品的热释光(TL)发光曲线和三维光谱.用90Sr的β射线辐照0.116～1.16 kGy后.测到的热释光峰发光曲线,观察到只有一个主剂量峰,峰温位于(231.5±2.3)C.用热释光一般级动力学方程拟合发光曲线,得到了峰参数和陷阱参数值.主剂量峰基本上不随照射剂量发生变化,辐射剂量响应为线性-亚线性.用+0℃oγ辐照100Gy后.测量了热释光三维光谱,确定了发光波长主要位于375nm.与其他硫酸盐基质材料中掺Eu的CaSO4Eu.MgSO4Eu比较.波长有所不同.可以确定这是来自于Eu2+能级跃迁的发光.     

MgB4O7:Tm,Mn磷光体的热释光特性

采用高温固相法制备了MgB4O7:Tm,Mn磷光体材料,测量了热释光发光曲线和热释光三维光谱以及剂量响应曲线。其主发光峰温度约为400oC,发光波长455 nm。MgB4O7:Tm,Mn主发光峰面积比LiF:Mg,Ti高6.2倍,具有很好的热稳定性,在0.1–2000 Gy范围内具有良好的线性-超线性剂量响应。     

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.     

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.     

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.