医用回旋加速器的选择

第二次世界大战以前,当时还没有反应堆,但是已经知道用人工方法制备放射性同位素,这时回旋加速器是实际上可用来制造人工放射性同位素的唯一工具。早期应用的放射性同位素实际上绝大多数是靠回旋加速器提供的。第二次世界大战以后,由于核反应堆的迅速发展,反应堆制造的同位素的数量和品种比加速器制造的要多,而且价格也便宜,因此很长一段时间对于用回旋加速器来制备放射性同位素未予以足够重视。     

放射性同位素在研究金属中偏析和非金属夹杂物方面的应用

放射性物质的发现已经六十多年了,人造放射性同位素的发现也有二十七年了。但放射性同位素在冶金方面的广泛应用,还只是最近十余年来的事情。因为只有建成原子反应堆后,才能大量生产人造放射性同位素。目前人造的放射性同位素已经超过一千种,但是有好多的放射性同位素的半衰期很短,不适于研究应用,比如象氧、氮、铝、镁等这些在冶金中重要的元     

示踪技术的工业应用

自1913年第一次放射性示踪剂实验以来,尤其在人工放射性同位素能够提供之后,示踪技术已经在许多领域得到应用。 现在也可以使用天然稳定同位素进行示踪技术研究,但检测这些稳定同位素所用的仪器是核磁共振谱仪与质谱仪。由于稳定同位素及其测试仪器的价格还很昂贵,因此稳定同位素示踪技术目前还只能作为放射性同位素示踪技术的一种补充手段。本文所讨论的只涉及放射性同位素示踪技术的工业应用。     

Si(Li)~(133)Xe探测器

一、引言~(133)Xe是惰性气体氙的一种人工放射性同位素。由于它具有γ射线能量低(81 keV)、     

列宁格勒州和圣彼得堡市放射生态研究结果

圣彼得堡是国家放射性地球化学的诞生地,而且在不同时期都对天然和人工放射性核素进行了研究。在该市建立了应用放射性同位素的生产,并广泛使用其产品,而且直到60年代初几乎是免检的。     

美国的同位素

美国原子能委员会同位素管理局局长艾贝索里德在日本第四次放射性同位素会议上,宣布了关于美国在生产和应用放射性同位素方面的如下资料。目前美国大约有1900个工业企业拥有使用放射性同位素的许可证。每年接受放射性同位素诊断研究的病人约有50万;每年利用放射性同位素治疗的病人超过了10万人。放射性同位素也广泛地应用在农业方面。原子     

我国放射性同位素制备技术的发展

放射性同位素在国民经济发展、人民健康水平保障等方面起着非常重要的作用。本文对我国放射性同位素制备技术的发展情况进行了简要回顾,重点回顾了近三十年来放射性同位素制备技术的发展情况,着重分析了~(14)C、~(60)Co、~(99)Mo、~(123/125/131)I、~(177)Lu等重要放射性同位素制备技术的研究进展,分析了我国在放射性同位素生产方面存在的问题,并对今后我国放射性同位素制备技术和生产的发展提出了建议,以期进一步促进我国放射性同位素技术的发展,进而为全面实现国内放射性同位素自主化生产服务。     

人工引雷高能辐射观测及数据分析研究

本文基于NaI（Tl）探测器搭建了人工引雷高能辐射观测系统。观测到了人工引雷产生的X射线爆发现象,4次成功的人工引雷实验中观测到3次X射线爆发信号。分析发现,人工引雷先导梯级过程的脉冲信号与高能辐射的脉冲信号具有一一对应的特征,表明先导梯级过程可能是闪电高能辐射的产生根源。     

利用核技术研究农药在环境中残留和代谢的进展概况

一、历史发展情况 早在1923年赫维西(Hevesy)就使用了天然放射性元素铅,观察了铅在植物体内的吸收和分布。1931年坎贝尔(Campbell)试验了由天然放射性元素铅标记的砷酸铅在蚕体内的吸收、分布情况。这是二个较早的应用放射性同位素研究铅在动物植物体内的吸收和分布的试验。同位素示踪技术作为农药残留和代谢的研究手段,还是在1943年建立核反应堆生产了人工放射性同位素以后,而这方面的研究工作较多的开展,更是在五十年代以后。起初利用放     

我国放射性同位素制备技术的发展

放射性同位素在国民经济发展、人民健康水平保障等方面起着非常重要的作用。本文对我国放射性同位素制备技术的发展情况进行了简要回顾,重点回顾了近三十年来放射性同位素制备技术的发展情况,着重分析了¹⁴C、⁶⁰Co、⁹⁹Mo、^123/125/131I、¹⁷⁷Lu等重要放射性同位素制备技术的研究进展,分析了我国在放射性同位素生产方面存在的问题,并对今后我国放射性同位素制备技术和生产的发展提出了建议,以期进一步促进我国放射性同位素技术的发展,进而为全面实现国内放射性同位素自主化生产服务。     

天然中子源中子测水技术的初步研究

论述了基于天然中子源的中于测水技术基本原理、仪器设备与方法技术以及在成都地区某地的试验结果。与人工中子源中子测水技术相比．虽然大气中子源方法的灵敏度较差．但避免了人工中子源的辐射防护与管理难题。这对于一些确定地层含水率要求不高．而又需长期监测的场合．如工程地质填图与地质环境动态监测等．天然中子源方法中子测水技术具有一定的应用价值。     

Transport and Deposition of Metals in Sodium-Stainless Steel Systems, (II)

Making use of the radioisotopes of manganese, zinc and antimony, to represent radioactive corrosion products, and a radioisotope of cesium as representative fission product, the transport and deposition of these radioisotopes in a natural circulation sodium loop have been studied over a temperature range from 630°C down to 280°C.

The movement of the radioisotopes during the loop running were monitored byin situ counting and radiochemical analysis of sodium samples taken from the loop. The distribution of the radioisotopes over the various cross sections along the cooling tube were determined after quick solidification of flowing sodium by chilling.

The results indicate that manganese deposits on the substrate materials presumably by adsorption in the higher-temperature region and by precipitation in the lower-temperature region, zinc presumably by adsorption associated with plating in the lower-temperature region, antimony by coprecipitation with other deposits in the cold settling pocket, and cesium mainly by physical adsorption in the lower- temperature region.

Significant deposition of the radioisotopes was observed in the pocket and the apparent rate constants of the deposition were obtained for manganese, zinc and cesium.     

Time Evolution of Artificial Plasma Cloud in Atmospheric Environment

By analyzing the time evolution of artificial plasma cloud in the high altitude of atmospheric environment, we found that there are two zones, an exponential attenuation zone and a linearly attenuating zone, existing in the spatial distribution of electron density of the artificial plasma clouds. The plasma generator‘s particle flux density only contributes to the exponential attenuation zone, and has no effect on the linear attenuation zone. The average electron density in the linear attenuation zone is about 10^-5 of neutral particle density, and can diffuse over a wide rarea, The conclusion will supply some valuable references to the research of electromagnetic wave and artificial plasma interaction, the plasma invisibleness research of missile and special aerocraft,and the design of artificial plasma source.     

核电站废树脂清洁解控问题探讨

对轻微污染的废树脂采取解控处理是核电站废物最小化工作的重要内容。在介绍近几年开展的核电站废树脂解控监测工作的基础上,对核电站目前的废树脂废物管理中存在的问题进行了总结,提出了有利于实施废树脂废物最小化的技术途径。解控后的废树脂可能采取的处置出路包括危险固体废物填埋处置和水泥窑协同处置,暂时尚不具备进行高温焚烧处置的条件。为了提高核电站这类废物最小化的实施效率,建议对不同类型放射性核素在废树脂中含量的相关性问题,对放射性核素在离子交换柱树脂中的空间分布问题,对废树脂分拣的在线监测技术以及其它类型固体废物的分拣监测问题等进行深入研究,以期在保证取样代表性的同时,减少取样量和测量工作量,提高工作效率,降低废物最小化的经济成本。     

Possibilities for Producing Radionuclides in Nuclear Power Plants with RBMK Reactors

It is shown that radiation doping of silicon and the production of medical and industrial radioisotopes in the reactors at the Leningrad nuclear power plant are possible and safe. The production of cobalt with specific activity ~100 Ci/g in an RBMK-1000 reactor is studied. Some promising developments for improving the quality of the radioisotopes produced are described. It is shown that the production volumes can be increased by linking up other nuclear power plants with RBMK reactors into the production chain.     

Improvement of Bragg Curve Detector Using in CIAE-AMS

Isobar identification method is the most important factor for the high-resolution and high-accuracy measurement in the AMS technology. The Bragg detector has the relatively high energy resolution, so the Bragg detector used for AMS measurement can improve the isobar identification, especially for the medial heavy radioisotopes. This can supply the important method for the medial heavy radioisotopes AMS measurement. We re-tested and improved the electronic signal obtaining way systemically,     

Denial of shipments — no longer 'myth' but 'reality'

Abstract

The global healthcare sector depends on shipments of radioisotopes. With the growing demand for radiation and radiation technology to prevent, diagnose and treat disease, it is vital that the global healthcare industry has a secure and reliable supply of such important materials. Despite this ever-increasing need, shipments of radioisotopes are being increasingly delayed and outright denied. This paper outlines the importance of radioisotopes in global healthcare, portrays examples of shipment denials, the implications for countries that depend on international supply and the steps being taken in response. Denial of shipment has been gaining international attention. A foundation is being laid for taking action. Awareness of the problem is increasing and international organisations are becoming involved. While actions are being taken to address this issue, the reality remains that refusals to accept radioisotopes are occurring in countries, ports and among carriers. MDS Nordion manufactures and distributes radioisotopes used in medicine, research and sterilisation industries throughout the world. As a responsible partner in a unique industry, it joins other radioisotope producers, carriers, suppliers and customers/users of these products in encouraging continued attention to this matter. A collaborative approach is necessary, given the highly interactive global system of transport.     

Heating frequency optimization for artificial field-aligned scattering

In this study, we present a simulation study of artificial field-aligned irregularities (AFAI) to calculate the scattering coefficient considering a Gaussian autocorrelation function for the wave number spectrum of the density fluctuation. By analyzing variations in the scattering coefficient under different ionospheric backgrounds, the optimal range of the heating frequency was found, which is about 0.9–1 times the critical frequency of the F2 layer. This is especially noticeable as when the heating frequency varies from 0.5 times to 0.9 times of the critical frequency, the scattering coefficient increases by 6.8–16.2 dB. These results should be useful for optimizing the heating frequency in the future artificial field-aligned scattering (AFAS) transmission applications at middle and low latitudes.     

Alpha induced reactions on Cd up to 38.5 MeV: Experimental and theoretical studies of the excitation functions

The energy dependence of the cross sections of threshold reactions induced by alpha particles on targets of natural cadmium is studied in the energy range from threshold up to 38 MeV. Using a stacked foil irradiation technique and classical gamma-spectroscopy the formation of the radioisotopes ^{110,113m+g,117m}Sn, ^{108m,g,109g,110m,g,111cum,113m,114m,115m,116m,117m,g}In and ^111m,115gCd was assessed. The newly obtained excitation functions were compared with earlier published values, measured either on enriched or natural Cd targets. The results of calculations based on theoretical models of nuclear reactions obtained by the codes ALICE-IPPE, EMPIRE and GNASH are presented. Thick target yields and production routes for some medically relevant radioisotopes are discussed.