keV/MeV能量可切换加速结构设计与调配

电子直线加速器广泛应用于无损检测及放射治疗领域,能量大范围可调有利于实现物质识别和精准放射治疗。本文介绍一支keV/MeV能量可切换驻波加速管的设计与调配。该加速管采用双周期边耦合结构,工作频率为2 998 MHz。经过优化设计,整管由2个聚束腔和5个加速腔构成,通过在边耦合腔中使用能量开关调变加速电场分布,从而实现450 keV、6 MeV两档能量的切换输出。经过精密加工及整管测试调配,实现了高低两档束流能量所需的电场分布可调,验证了设计的合理性。     

14MeV医用驻波加速管的微波调试

介绍了１４ＭｅＶ医用驻波加速管的微波调试情况。该加速管的加速能量与束流多档可调，可提供６、１５ＭＶ两档Ｘ射线和６—１４ＭｅＶ五档的电子线。该加速管总长１．４５ｍ，采用轴耦合双周期π／２模驻波结构。利用峰值２．６ＭＷ的脉冲磁控管为功率源，工作频率为２９９８ＭＨｚ，脉冲宽度４μｓ，重复频率为２５０ｙｓ。通过调节入口微波功率、电子枪的注入电压、电流等参数，实现加速管的能量调变     

C波段9 MeV驻波电子直线加速管设计

介绍了C波段驻波电子直线加速管的研制情况.该加速管采用2.5 MW脉冲磁控管为微波功率源,脉冲宽度4μs,重复频率250 MHz.可提供能量为6 MeV和9 MeV两档能量的电子束,工作频率为5712 MHz,管长约620 mm.通过调节加速管的入口功率、电子枪的注入电压实现加速管的输出能量两挡调变.     

用蒙特卡罗方法研究球形充气电离室的能量响应特性

环境γ辐射监测用的电离室要求平能量响应。为使球形不锈钢充氩电离室达到能量响应指标，采用蒙特卡罗方法对充气电离室体积、壁、充气气体、收集极、屏蔽材料、屏蔽厚度及屏蔽面积等因素进行模拟计算，为改善能量响应特性和拓展最低探测能量提供依据。     

14MeV医用同源双模中能电子直线加速管的研制

医用同源双模中能电子直线加速管是影像引导放射治疗技术(Image Guide Radiation Therapy,IGRT)中的核心部件,为确保放射治疗直线加速器能够提供稳定和高品质的成像射束、双光子模式治疗射束以及多档电子射束,上海联影医疗科技有限公司研制了基于一种新型的能量开关技术的14 Me V医用双模驻波加速管。采用束流动力学程序Parmela对加速管整管的横向聚焦和纵向聚束进行了动力学设计分析,为优化加速管腔体几何结构提供了指标要求,最终利用电磁场仿真软件Superfish及CST(Computer Simulation Technology)优化腔体结构设计并得到了最优的微波参数。模拟计算结果表明,该加速管总长1.3 m,采用边耦合双周期?/2驻波结构,工作频率2.998 GHz,其输出束流能量可以实现多档可调,成像模式可输出低于3 MV的光子,治疗束可输出具有6 MV和10 MV两档的光子及4档能量电子束(最高能量可达14 Me V)。完成加工后,冷测结果与设计值符合得比较好,下一步将进行高功率微波老练。     

DZ-12/4多能量档电子直线加速器辐照关键参数测试

中国原子能科学研究院建立了一台DZ-12/4多能量档电子直线加速器,该装置主要用作辐射加工级电子束辐照实验平台。为了检测该电子束辐照实验平台辐照工艺控制参数,本文利用中国原子能科学研究院FJL-02型辐射变色薄膜剂量计对DZ-12/4多能量档电子直线加速器关键参数能量进行了测量,并对研制的束流监测系统法拉第筒的可靠性进行了验证。结果表明,DZ-12/4多能量档电子直线加速器能量在4~12 MeV范围可调,运行参数准确可靠;日常运行中,加速器运行人员通过监测设备和调节加速器参数可有效控制并估计辐照剂量,具有非常好的实用性和简便性。     

100 MeV质子回旋加速器二期辐照效应管道设计

针对中国原子能科学研究院100 MeV质子回旋加速器上的单粒子效应辐照装置进行了二期管道设计,采用八极磁铁校正法对束流进行了扩束及均匀化,最终在靶上得到了一个30 cm×30 cm、均匀性好于92%的均匀分布的束斑,满足了单粒子效应实验的需求。为降低靶站处的束流能散及中子本底,采用两级降能的方案,在偏转磁铁前放置1个降能片,将能量分为100 MeV和40 MeV两档,并分别针对这两个能量点进行方案设计,束流利用率均在42%以上。公差分析结果表明,四极磁铁对靶上束斑均匀性的影响大于八极磁铁,安装过程中应优先保证四极磁铁的安装公差。     

100 MeV质子回旋加速器二期辐照效应管道设计

针对中国原子能科学研究院100 MeV质子回旋加速器上的单粒子效应辐照装置进行了二期管道设计,采用八极磁铁校正法对束流进行了扩束及均匀化,最终在靶上得到了一个30 cm×30 cm、均匀性好于92%的均匀分布的束斑,满足了单粒子效应实验的需求。为降低靶站处的束流能散及中子本底,采用两级降能的方案,在偏转磁铁前放置1个降能片,将能量分为100 MeV和40 MeV两档,并分别针对这两个能量点进行方案设计,束流利用率均在42%以上。公差分析结果表明,四极磁铁对靶上束斑均匀性的影响大于八极磁铁,安装过程中应优先保证四极磁铁的安装公差。     

碘化钠(铊)闪烁晶体的制备

一、引言我们从1961年开始研究碘化钠晶体的生长,在缺乏技术资料的情况下,自己设计和制造了结晶炉,采用常用的引上法,对碘化钠(铊)单晶体生长条件进行了多次试验。在1964年试制成功了φ32×20毫米透明度良好的NaI(Tl)晶体,其能量分辨率达到8—11%。1965年,     

MC模拟碘化钠探测器能量响应及其优化设计

碘化钠探测器对不同能量的γ射线存在不同的能量响应,为了使其测量γ辐射剂量的准确度达到要求,需要对碘化钠探测器进行能响补偿。本项目利用MCNP软件,模拟尺寸为Φ30 mm×20mm的碘化钠晶体在不同铅屏蔽体模型下的能量响应;通过比较不同模型下能量响应的标准偏差,选出最佳铅屏蔽体的形状和尺寸。模拟得出铅屏蔽体的尺寸在4 mm厚度,小孔半径r为6.7 mm(暴露面积20%)时,碘化钠晶体的能量响应最好。通过实验验证,理论数据与实验数据基本一致。     

Progress in ECRF antenna development for JT-60SA

Structural, mechanical and optical design work on antennas/launchers for the electron cyclotron range of frequency heating and current drive system in JT-60 Super Advanced (JT-60SA) have been advanced based on a linear motion antenna concept. A CAD model of the launcher was built with realistic component sizes. A mock-up of the steering structure consisting of two different bellows sections for poloidal and toroidal beam scanning was fabricated to test movement of the bellows. The poloidal (?40° to +20°) and toroidal (?15° to +15°) injection angle ranges required in JT-60SA were shown to be realized by this steering structure and mirrors.     

BF3长计数器效率刻度及其应用

利用²³⁸U裂变反应，通过测量裂变碎块的数量，能够较为准确地测量快中子注量。但这种方法在中子能量为1.6MeV以下（裂变道未开或处于裂变截面第1个台阶上升处）和6.0～7.0MeV能区（第2个台阶上升处）由于不确定度过大而不适用。本工作采用4种不同的核反应作中子源，对北京大学4.5MV静电加速器中子实验大厅的BF₃长计数器的相对效率进行了刻度。将²³⁸U(n,f)反应与相对效率已知的BF₃长计数器相结合，解决了在上述能区准确测量中子注量的问题。      

3 MV加速器质谱测量36Cl

在端电压为3 MV的AMS装置上实现³⁶Cl及其他中重核素的高灵敏测量是AMS技术发展的重要方向之一。为进一步提高充气飞行时间探测方法中³⁶S的压低能力,本文研究了³⁶S和³⁶Cl在P10、异丁烷和丙烷气体中的能量歧离和角度歧离。在32 MeV的入射能量下测量了几个地下水样品中³⁶Cl的[JP2]含量,测量结果与72 MeV能量下的测量结果相符。测量结果表明,采用充气飞行时间探测方法在3 MV的串列加速器上测量³⁶Cl时,探测限为³⁶Cl/Cl≈10^-14,当样品中³⁶Cl/Cl≈10^-13时测量不确定度为30%。     

The novel ultrastable HVEE 3.5 MV Singletron accelerator for nanoprobe applications

Recently, HVEE has completed a novel 3.5 MV single ended accelerator (Singletron^™) for the University of Leipzig, Germany. For one of the main applications, the system will be connected to a nanobeamline to achieve submicron resolution. Because the energy stability and ripple of the beam, and beam brightness are of vital importance for the performance of a nanoprobe, special care has been taken in optimizing these parameters. The system consists of an RF source which is directly mounted on the accelerator tube, a switching magnet to bend the beam into a chamber for standard analysis purposes and an analysis magnet that directs the beam into the nanoprobe. The stability of the beam energy was measured at a terminal voltage of 1.881 MV. These measurements were taken during factory acceptance with large production equipment operational, which negatively influenced the stability of the mains. The measured stability was found to be approx. ±50 eV over 5 h, but it is anticipated that this figure will be as good as ±20 eV (i.e. 10⁻⁵) under normal laboratory conditions. The terminal voltage ripple was measured at 2.25 MV to be 25 V_pp (i.e. 1.1 × 10⁻⁵). Finally, the beam brightness of a 2.25 MeV hydrogen beam was measured by the use of two micrometer slit systems. A brightness of approx. 18 Amps · rad⁻² m⁻² eV⁻¹ was obtained. In this article we will describe the considerations which have led to the layout of the present system.     

中国评价核数据库第二版(CENDL-2)

中国评价核数据库第二版（ＣＥＮＤＬ－２），包含从Ｈ到中的５４个重要核的全套评价中子核数据，中子能区为１０－５２０ＭｅＶ。它是在ＣＥＮＤＬ－１基础上，进行更新评价、扩展能区、扩充核素和数据种类；按国际标准格式建立计算机化核数据库；改进和发展理论计算、评价处理的有关方法和技术，研制配套相应的计算程序和基准检验程序系统；评价分析和理论计算细致，部分核的评价有自己的特色，较国际上先进的评价核数据库有所改进，有些评价数据还被这些先进库所采用。国际原子能机构已把ＣＥＮＤＬ－２作为国际上最先进的５个主要评价核数据库之一向世界各国发行，提供使用。     

The Schonland Micro-Scanning Ion Beam Analysis Facility

The Schonland Micro-Scanning Ion Beam Analysis Facility is used for interdisciplinary research, uniting physics and many other disciplines. It has a unique dual accelerator input configuration. A wide range of high energy heavy and light ions is available from an EN Tandem van de Graaff accelerator with 6.0 MV terminal voltage. Light ions at lower energy but with much increased luminosity are available from a 2.5 MV single-ended van de Graaff accelerator. The sample chamber is equipped to image radiation and particles from a wide range of ion-beam interactions with matter. These include the ion beam analytical techniques of RBS, ERDA, PIXE, NRA, SecEM and STIM. Some of these techniques have been performed tomographically or under channeling conditions. Sub- or near-micron spot sizes for many of these techniques are available. The user interface to the sample chamber is highly automated, allowing safe and friendly interaction. The OMDAQ system developed at Oxford University is dedicated to on-line acquisition and preliminary analysis of singles spectra. The Physics Analysis Workstation (PAW + +) system developed for CERN and ported to a CAMAC-PC environment manages the more sophisticated multi-parameter acquisition and post-processing.     

The VEBA Relativistic Electron Accelerator

The VEBA high-current, relativistic electron accelerator has been designed and constructed at NRL for application in the study of high-power microwave sources. To meet the requirements of this study, the accelerator was designed for operation in either a short (60 nsec) or long (2.2 ?sec) pulse mode. The short-pulse mode has been in operation for nearly two years and has proven to be an extremely reliable design. The design of the long-pulse mode is now complete and component fabrication will soon be underway. The pulse-forming network in the short-pulse mode is an unbalanced, water Blumlein with an output impedance of 9.2? The Blumlein is pulse charged by a 17 stage Marx generator which has a series capacitance of 29.4 nF. By transmission along a tapered coaxial line, the output pulse is transformed to 20 ? and the voltage developed across a matched load increased to a maximum of 2.5 MV. The proposed conversion to the long-pulse mode will require that the Blumlein and transformer sections be removed and the diode assembly be attached directly to the oversized Marx tank. The direct coupling between the Marx and the Blumlein will then be replaced by two, nested, water capacitors which are shunted by spiral inductors. When coupled in series with the Marx, this output filter will form a three-section, voltage-fed, Guillemin (type A), pulse-forming network with a characteristic impedance of 40 ? and a maximum output voltage of 0.9 MV.     

0.96-2.74MeV质子在铝上的160°散射截面测量

采用薄靶对能量0.962.74MeV质子在纯度为99.99%铝上的160非卢瑟福弹性背散射截面进行了测量。质子束由21.7MV串列加速器提供,测量仪器采用金硅面垒探测能谱仪。实验中最低能区进入卢瑟福弹性散射能区,测量结果用图表形式给出,并与以前发表的结果进行了比较。所测量数据可供从事背散射分析技术的有关人员参考。