Grid-Controlled Power Tubes in Particle-Accelerator Applications

Typical illustrative examples are cited for the use of grid-controlled power tubes in the various classes of particle accelerators, e.g., cyclotrons, synchrocyclotrons, proton synchrotrons, electron synchrotrons, and linear accelerators, A state-of-the-art review of triode and tetrode power-tube technology is presented, together with some apparent trends in the design and development of new tubes. The use of triodes and tetrodes with integral cavity-resonators enhances the feasibility of their use at increasingly higher frequencies and/or power levels. In addition to their use as radiofrequency generators in particle accelerators, grid-controlled power tubes are also applicable as pulse modulators and amplitude regulators. The unique advantages of gridded power tubes for particle accelerators are discussed.     

加速器对环境的放射性影响

加速器对环境的放射性影响主要是由于屏蔽不良和活化引起的。影响的主要途径是中子的天空反射和感生放射性气体的扩散。采取严格的防护措施后,对环境的影响是微乎其微的。回顾世界加速器运行历史经验,也没有发现对环境产生过明显的污染。     

加速器束团长度测量

随着技术的不断发展,近年来出现了多种加速器束团长度的测量方法,主要有条纹相机测量、迈克尔逊干涉仪测量、电光晶体测量、耦合束流频谱测量等。本文综合介绍了这些方法,并指出各种方法都有自己的优缺点及适用范围。目前国际上各大型加速器实验室普遍采用的是条纹相机测量方法,对于自由电子激光等超短束团一般都是采用光学技术、频域方法测量,有些测量法的分辨率可达到飞秒级,提供了具有更高空间分辨率、更高时间分辨率的强有力研究手段。     

Sterilization complexes based on ILU-type electron accelerators

This paper describes the industrial electron accelerators of the ILU type and their usage for sterilization.The ILU machines produced by Budker Institute of Nuclear Physics have energy range of 0.8-10 MeV and beam power up to 100 kW,and they are working in industries all over the world.The ILU-10 and ILU-14 machines are described as well as the industrial sterilization facility based on ILU-6,ILU-10 and ILU-14 machines.     

Use of particle reflection in curved crystals to improve beam collimation in a ring accelerator

The staff of the Institute of High-Energy Physics together with researchers from Russian and foreign scientific centers have discovered a new physical phenomenon – reflection of fast charge particles in curved crystals. This article presents the first experimental results using multiple reflections of protons in silicon crystals to increase the beam collimation efficiency in the U-70 accelerator. The experimental data are compared with theoretical models. The technology developed using reflecting crystals can be used to form oppositely propagating beams in accelerators and has prospects for extracting low-emittance beams on ~1 GeV accelerators for electronuclear facilities and in medicine and industry.     

RADIATION HAZARD AND PROTECTION OF LOW ENERGY ACCELERATORS

In this paper,the origin and type of radiation hazards as well as the main aspects of radiation protection for low-energy accelerators are discussed in general,and the problems of radiation protection and the experimental results of the operational monitoring of the five accelecrators in the Institute of Nuclear Science and Technology,Sichuan University,namely,one 1.2M cyclofron,two Cockroft-waltons and two Van de Graafts,as well as a powerful electron accelerator for industrial irradiation are described.The discussion and evaluation are made according to the requirments of the national standards GB5172-85.     

Economic Scale of Utilization of Radiation (I): Industry Comparison between Japan and the U.S.A

Utilization of radiation in the industrial field has been enlarged due to the variety of technologies. In the present paper, the economic scale between the U.S.A. and Japan is compared with selected industrial parameters such as sterilization, semiconductors, radiographic testing (RT) and radial tire production because the very large industrial markets make a whole comparison difficult. The economic scale revealed was about 56b$ (1$=121¥) for the U.S.A. and 39b$ for Japan. The former is large in magnitude by a factor of 1.4. With respect to the relative ratio versus the GDP, the former was 0.7% and 0.9% for the latter. This implied that utilization of radiation in industry is large in magnitude and is expected to be further developed. Regarding electron beam (EB) accelerators, for example, 648 units were installed in North America and 308 units for Japan during the past 29 years. The large number of the former is attributed to use in curing and heat shrinkable tubes (film).     

DG系列大功率工业辐照电子加速器

中国科学院近代物理研究所成功研制了DG系列中频变压器型工业电子加速器,其中DG-2.5型加速器能量范围1.0-2.5 MeV,最大束流功率90 kw,束流扫描有效宽度1000 mm,适用于各种辐照领域;DG-1.2型能量范围0.8-1.2 MeV,最大功率50 kw;这两种型号加速器均通过了长时间测试,工作稳定、故障率低,采用计算机自动控制,并可与束下传动系统连锁,完全达到了工业应用的标准.     

小型粒子加速器人身安全联锁系统设计与实现

20世纪30年代以来,世界上运行中的粒子加速器已超过3万台,其中用于科研的大型粒子加速器有200台左右。粒子加速器在运行过程中会产生对人体有害的电离辐射,为保障工作人员在联锁控制区内的人身辐射安全,避免出现辐照事故,需建立一套人身安全联锁系统。本文利用全硬件、模块化的设计思想,基于PLC、置换型机械联锁钥匙、自主研制的急停/巡更装置及摄像监控等一系列硬件设备,专门为小型粒子加速器研制了人身安全联锁系统。该系统在加速器驱动的次临界系统（ADS）注入器Ⅰ和中国科学院高能物理研究所（IHEP）加速器电子标定束线装置两个项目中至今运行稳定可靠,并可推广应用于工业辐照装置。     

Wide-Aperture Electron Accelerators

Wide-aperture low-energy electron accelerators, which provide simultaneous irradiation of large surfaces and volumes, are used in radiation technology, ionization setups for gas lasers, and in scientific research. Certain modifications of wide-aperture electron accelerators – ionization setups for CO and CO₂ lasers and ozone generator based on an electron-beam-controlled discharge – are described.     

《工业X射线探伤放射卫生防护标准》在环境影响评价中的几点探讨

固定式X射线探伤项目的环境影响评价中,职业卫生标准《工业X射线探伤放射卫生防护标准》(GBZ 117-2006)(以下简称GBZ 117-2006)为主要使用的技术标准与评价依据之一。针对固定式X射线探伤环境影响评价过程中遇到的实际问题,包括探伤房曝光室的屋顶、通风孔、电缆管口以及防护门等辐射防护薄弱环节,从实践性与可操作性方面展开讨论,对GBZ 117-2006提出完善与细化的建议。     

加速器制备医用放射性同位素的现状与展望

加速器制备核素以其独特的自身优势成为制备放射性同位素的重要方式之一,在进入新世纪后作用与地位日益突出。本文对国内外加速器制备医用放射同位素技术的发展现状进行了简要概述,着重分析了¹⁸F、⁶⁴Cu、⁶⁸Ge/⁶⁸Ga、⁸⁹Zr、¹¹¹In、²¹¹At、²²⁵Ac等重要医用放射性核素研究进展,并对我国加速器制备医用同位素的应用前景进行了展望。     

A new generation of single-ended Van de Graaff accelerators for ion implantation and ion beam analysis

High voltage Engineering Europa B.V., The Netherlands developed a new generation of single-ended Van de Graaff accelerators for ion implantation and ion beam analysis. The new HVEE Van de Graaff accelerators are equipped with a unique (patented) ion source exchange system capable of handling four lands of ion sources, mass separation at high voltage level and an X-ray intensity suppression system. The accelerators are able to produce a large variety of continuously, homogeneous and highly collimated mass-analyzed ion beams of several hundred μA in the energy range from 50 keV up to l MeV (l MV model) or from 100 keV up to 2 MeV (2 MV model), using singly charged ions, whereby the maximum energy can be easily reached and maintained without conditioning and virtually no X-rays are produced. Combined with two dedicated end stations (one for ion beam analysis using RBS, channeling, NRA and PIXE, and one with an automatic wafer-handling system for both single-wafer implantation and batch processing), these systems are very suitable for research as well as industrial applications.     

Denial of shipment of radioactive material

Abstract

Radioactive sources are used globally in a wide range of beneficial applications in the health care industry, in industrial exploration and development, as well as in basic scientific research and discovery. In fact, some 45% of the world’s medical disposable products are gamma sterilised using cobalt-60 in processing plants located around the world. Other vital applications such as cancer treatment, nuclear medicine, oil exploration and industrial radiography routinely and extensively use radioactive sources. In addition, radionuclides and radiopharmaceuticals are used tens of millions of times every year in the diagnosis and treatment of disease in patients globally. The ability to use such radioactive materials in these sectors is dependent on their safe and secure transport both within and between countries, to ensure that both developing and developed countries have access to this technology in a timely and cost effective manner. However, delay and/or denial of shipment of radioactive materials is having a negative impact on the timely availability of this safe and beneficial technology. What are some of the key reasons for denial of shipment? How serious is this issue and what is its impact on industry and the public? What are international agencies, non-government organisations, regulators and industry doing about it? In 2009 and 2010, International Source Suppliers and Producers Association chaired the International Steering Committee on the Denial of Shipment of Radioactive Material. What are some of the key actions that the International Steering Committee has undertaken? What accomplishments have been achieved and what areas still require international effort among key stakeholders? This paper provides industry perspectives on how the issues causing denial of shipment can be addressed, and how dealing with the root causes of denials will have marked positive impact on the industry and public who rely on them each and every day. Further, this paper provides some examples to show how International Source Suppliers and Producers Association and other industry associations such as Industrial Irradiation Association, Council on Radionuclides and Radiopharmaceuticals and Association of Imaging Producers and Equipment Suppliers have and will continue to be actively involved in addressing this issue.     

X-rays Production by 15-55 MeV Carbon Ions Striking Metal Surfaces

A-100区奇奇核存在着丰富的核结构信息，例如形状共存、三轴形变、带终结以及磁转动带与手征二重带等。在前人的实验结果中，^112In的高自旋态信息很少，仅观测到10ˉh。本次实验的目的是为进一步研究^112In的高自旋态结构，并且寻找其可能存在的磁转动带与手征二重带。     

Spark source for multiply-charged ions

Most well-known spark sources for multiply-charged ions make use of weak inductively-coupled sparks which are obtained by means of a Tesla coil [1], [2]. These sources have not been used in charged-particle accelerators because of the small ion current, low charge multiplicity of the ions which are obtained, and general unstable operation. Starting in 1953 the authors have been carrying out an investigation of “hot” vacuum sparks obtained by the discharge of high-voltage condensers in an effort to obtain intense beams of multiply-charged ions with high charge multiplicities. In 1954 a source was constructed and found suitable for use in pulsed accelerators of multiply-charged ions.     

A new tool to compare neutron and ion irradiation in materials

The slowing down of neutrons produced in nuclear plants or in spallation sources generates many defects in a material, driving this material far from its equilibrium state. This concentration of defects leads to important structural modifications of solids. To model the impact of radiation in solids, particle accelerators are useful tools. The nature and the energy of ions in accelerators must be chosen to produce similar effects to those occurring in nuclear plants. A new program, DART, based on the binary collision approximation, has been developed to optimize the choice of incident particles. In this program, the anisotropy of the neutron atom interaction is treated with a new formalism. Such a formalism allows us to compute accurate displacement cross sections and recoil spectra for all kinds of particles (ions, neutrons, or electrons). The comparison of these displacement cross sections as well as recoil spectra due to ions, electrons and neutrons permits to define the nature and the energy of ions able to simulate damages in reactors.     

Advanced topics on RF amplitude and phase detection for low-level RF systems

Low-level radio frequency(LLRF) systems stabilize the electromagnetic field in the RF cavities used for beam acceleration in particle accelerators. Reliable, accurate, and precise detection of RF amplitude and phase is particularly important to achieve high field stability for pulsed accelerators of free-electron lasers(FEL). The digital LLRF systems employ analog-to-digital converters to sample the frequency down-converted RF signal and use digital demodulation algorithms to calculate the RF amplitude and phase. Different sampling strategies and demodulation algorithms have been developed for these purposes and are introduced in this paper. This article focuses on advanced topics concerning RF detection,including accurate RF transient measurement, wideband RF detection, and RF detection with an asynchronous trigger, local oscillator, or clock. The analysis is based on the Swiss FEL measurements, but the algorithms introduced are general for RF signal detection in particle accelerators.     

The role of nuclear data for fusion technology studies

Nuclear data are of fundamental importance in studies of nuclear technology. In these studies, experiments to measure cross sections and decay properties and simulations of the design of fission power plants, fusion devices and accelerators are included. The large amount of data required is stored in computer readable formats in data libraries and the most common of these are the general purpose files used for neutronics or transport calculations. These files also contain the standards against which most measurements are made. The other class of libraries are the special purpose ones containing decay data, fission yields and cross section data for dosimetry and activation.This paper gives examples of what data are available and describes their use for various fusion applications. The focus will be on neutron-induced activation data with examples of how the reactions of particular importance can be identified. All data should be accompanied by estimates of the uncertainty. This is best achieved by including covariance data; however, this is extremely challenging and only a subset of the available data has such uncertainty data. The general principles of how covariance matrices are used are outlined.