在线同位素分离器监控系统的研制

在线同位素分离器(ISOL)装置是HI-13串列加速器升级工程中产生放射性核束及13 MeV串列加速器的注入部分，其能产生多种放射性核束，具有高质量分辨率的特点。为实现该装置的监控任务，结合ISOL的分布情况和特点，设计了一套PLC框架下构建的基于以太网的分布式控制系统。本文介绍受控设备的特点、控制方式、监控系统的基本结构、安全联锁和抗干扰设计、图形化监控软件设计、数据存储方式及运行情况。     

Simultaneous acceleration of two kinds of ion beams in the RISP

The Rare Isotope Science Project(RISP) is a research complex consisting of a heavy-ion accelerator,which contains a front-end system, a super-conducting linear accelerator, an isotope separator online(ISOL) system, and an in-flight system. The original purpose of the post-linear-accelerator(post-linac) section was to accelerate either a stable driver beam derived from an electron cyclotron resonance ion source, or an unstable rare-isotope beam from an ISOL system. The post-linac lattice has now been redesigned using a novel and improved acceleration concept that allows the simultaneous acceleration of both a stable driver beam and a radioisotope beam. To achieve this, the post-linac lattice is set for a mass-to-charge ratio(A/q) that is the average of the two beams. The performance of this simultaneous two-beam acceleration is here assessed using two ion beams:~(58) Ni~(8+) and ~(132)Sn~(20+). A beam dynamics simulation was performed using the TRACK and TraceWin codes. The resultant beam dynamics for the new RISP post-linac lattice design are examined. We also estimate the effects of machine errors and their correction on the post-linac lattice.     

A fast-valve system for characterizing effusive-flow properties of vapor-transport systems: RIB applications

Decay losses, associated with the times required for particles to diffuse from ISOL production targets and to effusively-flow to an ion source, must be reduced to as low as practically achievable levels in order to deliver useful beam intensities of short-lived isotopes for research at ISOL based Radioactive Ion Beam (RIB) facilities. We have developed a fast-valve system and complementary 3-D Monte-Carlo code which can be used separately or in combination to assess the effusive-flow properties of vapor-transport systems, independent of size, geometry and chemical properties of the transport species. In this report, we describe the fast valve and present time spectra and characteristic time data for noble gases flowing through serial- and parallel-coupled vapor-transport systems similar in geometry but longer than those used for RIB generation at the HRIBF with and without target coating matrices.     

RIKEN isotope separator on-line GARIS/IGISOL

This paper describes the fabrication and the characteristics of an isotope separator on-line (ISOL) which was constructed at the RIKEN Ring Cyclotron Facility. The ISOL consists of a gas-filled recoil separator and an ion-guide isotope separator on-line. Because of this combination the ISOL enables us to study short-lived isotopes of almost all elements.     

Collection, cooling and delivery of ISOL beams

The collection of an ISOL beam in a Penning trap using implantation on a surface that is subsequently manipulated so as to become part of an end electrode of a Penning trap and reionization of the implanted material by heat has already been very productive for high-precision nuclear-mass measurements, even though it is limited to elements that are surface ionizable and the collection efficiencies are never better than about 0.1%. More recently, in 1990 a Paul trap system for electric collection of ions was installed at the ISOLDE-3 facility and collection was demonstrated for a 60 kV beam of ¹³²Xe ions. The purpose of this test setup was to determine the relationship between phase space volume of a typical trap and the collection efficiency that could be obtained in direct capture. For the modest trap used, collection efficiencies of up to 0.2% were achieved. A beam of negative bromine ions was collected by simply reversing the polarities of all voltages used. From the experience with this system it appears feasible to build a Paul trap which is about three times as large in linear dimensions as the existing one and which could be driven at up to 10 kV peak at 1 MHz using a modest rf amplifier (300 W). With moderate prebunching of the injected beam at 1 MHz, this system should achieve collection efficiencies approaching 100%. Based on these results, preliminary design work is being carried out on the collection system to be installed at the ISOLDE Booster facility. Suggestions for other uses of a Paul trap collection system for ISOL beams are presented.     

北京ISOL项目进展

北京ISOL（北京在线分离丰中子束流装置，亦简称BISOL）是由中国原子能科学研究院和北京大学联合提出的一台大科学装置。项目建设包括反应堆与加速器驱动放射性核束离子源、强流氘离子加速器、高功率靶站与核能材料辐照装置、放射性核束后加速器、放射性核束实验站等。装置建设方案已初步确定，装置建成后可产生较国内外现有装置强度高1~2个量级的极端丰中子束流，可开展学科基础前沿放射性核束物理的创新研究，同时兼顾先进核能系统开发和多种核技术应用的需求。     

放射性核束的产生

为适应国际核物理学的发展，开展放射性核束物理这一世界前沿工作，对放射性核束的产生和加速方面的多项工作进行了研究。文章简要介绍相关的离子源和加速器工程技术问题。     

HI－13串列加速器升级工程在线同位素分离器高质量分辨谱仪物理设计

HI－13串列加速器升级工程中的在线同位素分离器(ISOL)高质量分辨谱仪要求20000的质量分辨率。本工作采用大小铁双能量结构削弱能量色散，有效解决了束流能散过大导致的谱仪质量分辨率低的问题。结果表明：当束流高斯分布宽度为0.06mm和10mrad时，谱仪的质量分辨率达到了33400；若考虑加速段引入的0.002%能散，谱仪最终的质量分辨率为20000。     

大破口触发的严重事故分析及缓解措施研究

采用严重事故一体化分析程序MELCOR,对国产先进压水堆核电厂进行系统建模,选取大破口触发的严重事故进行校核计算研究,获得了严重事故工况下核电厂关键参数的瞬态特性和非能动系统响应特性,并与安全分析报告中MAAP的计算结果进行了对比分析。结果表明:虽然校核计算结果与安全分析报告中的结果存在一定差异,但总体上事故序列和主要参数的变化趋势吻合良好,并且都能够在严重事故情况下保持压力容器和安全壳的完整性,放射性裂变产物释放量极低,缓解措施的设计能够有效缓解事故进程,满足核电厂的安全要求。     

Fluorination method for the surface ionization of Sr and Ba with a helium-jet type ISOL

In order to realize the efficient and selective ionization of Sr and Ba isotopes with a He-jet type ISOL for fission products, a fluorination method has been investigated using a surface ionization ion source coupled with a skimmer system. The ionization characteristics have been studied as functions of the ionizer temperature and the CF₄ gas flow rate. It has been found that high ionization efficiencies for SrF and BaF can be achieved with a relatively low ionizer temperature (1900°C) similarly to the oxidation method for lanthanides. Elemental selection in the same mass chain can be done simultaneously by this method and pure Sr or Ba activities in fission products are available.     

钠冷快堆熔断式非能动停堆系统方案设计

为保证和增强池式快堆的安全性，通过对比分析现有的非能动停堆装置，基于将某些合金在特定温度下拉伸强度发生突变的特性作为钠冷快堆非能动停堆的触发条件，提出了一种钠冷快堆熔断式非能动停堆系统的设计概念，能在发生无保护超功率事故或无保护失流事故的情况下引入负反应性。针对中国实验快堆(CEFR)的设计完成了熔断式非能动停堆系统的方案设计论证，并利用分析程序DYN4G对这一非能动停堆系统在CEFR无保护事故下的响应情况进行了模拟计算，由此得到了其组件设计的关键参数。分析结果表明，通过合理设计，在发生无保护事故时，熔断式非能动停堆系统能有效降低事故情况下的堆芯燃料组件及冷却剂的温度，进一步提高了钠冷快堆应对严重事故的能力。     

An ion trap for nuclear laser spectroscopy at Tohoku ISOL

An on-line ion trap directly connected to the Tohoku ISOL has been constructed. The trap is aimed at the study of nuclear magnetic properties through precision measurements of ionic ground-state hyperfine structures of unstable nuclei. As a first step to a systematic study, the hyperfine splitting of the ground state of ⁸⁷Sr⁺ ions was measured by laser microwave double-resonance spectroscopy.     

空间核反应堆电源热工水力特性研究综述

随着空间探索领域的快速发展，研究高功率、安全、可靠的空间核反应堆电源将变得愈发重要。本文针对国内外空间核反应堆电源的热工水力关键问题，即空间堆系统稳态和事故瞬态研究、堆芯单冷却剂通道及全堆芯的三维流动换热、静态与动态热电转换装置分析、热工水力特性试验研究等进行研究，分析了空间核反应堆电源热工水力研究的趋势。本文结果可为空间核反应堆电源设计分析及热工水力安全特性研究提供帮助和指导。     

聚变堆氚分析程序TAS1.0的设计与开发

氚是聚变堆的重要燃料之一,对聚变堆氚系统进行分析从而实行有效的氚控制是聚变研究的重要内容之一.在中国系列液态金属锂铅包层聚变堆概念设计研究基础上,利用现代软件工程方法及面向对象技术设计思想,发展了聚变堆氚分析程序TAS1.0,可用于聚变堆氚自持分析、氚燃料管理及氚安全性分析与研究,并可为聚变堆包层及燃料循环系统设计与分析提供技术支持.通过一系列的测试校验,表明了该程序的正确性与有效性.本文主要介绍该程序的系统设计、技术特点与程序测试.     

先进压水堆核电厂保护系统需求分析的层次结构

为提高核电厂的安全性和运行裕量，本工作在已有技术的基础上自主进行核电厂数字化保护系统需求分析,完成需求分析报告。需求分析报告采用1种三等级的金字塔式层次结构，该结构可直观阐明先进压水堆核电厂数字化保护系统的设计特性和逻辑实现。     

The MEGAPIE 1 MW target in support to ADS development: status of R&D and design

The MEGAPIE project is aimed at designing, building and operating a liquid metal spallation neutron target as a key experiment on the road to an experimental accelerator driven system and to improve the neutron flux at the PSI spallation source. The design of the target system has been completed. The target configuration and the operating conditions have been defined and the expected performance assessed. A preliminary safety analysis has been performed considering normal, off-normal and accident conditions and a corresponding report has been submitted to the authorities for licensing. The experience gained up to now shows that MEGAPIE may well be the first liquid metal target to be irradiated under high power beam conditions.     

数字化反应堆功率控制系统

数字化技术对提高反应堆功率控制系统的可靠性、安全性和可维护性以及改善人机界面具有重要意义。文章描述一采用数字化技术设计的研究堆功率控制系统，介绍了功率控制方法、实现的功能、系统的结构、功率调节算法以及设计关键技术。由于采用了标准的数字化控制器，使功率控制系统可方便地集成到统一的控制系统中。     

基于软件无线电的新型数字束流位置处理器

研究了基于软件无线电架构的新型数字束流位置处理器,介绍了处理器样机的射频、模数转换和数字处理模块的硬件架构和主要参数。针对处理器多通道的不对称性,提出了校准方案。测试结果表明,处理器逐圈位置电子学分辨率在输入大于–30 dBm时,优于1.5μm;输入大于–27 dBm时,电子学分辨率达到亚微米量级。处理器在上海光源储存环流强为150 mA条件下测试,逐圈位置分辨率优于2μm,并能够准确获取包含束流实时信息的逐圈位置信号。     

在线穆斯堡尔谱测量装置

穆斯堡尔效应自从被发现以来,已经成为研究超精细相互作用的不可缺少的工具,具有十分广泛的应用.然而其应用又受限制于一些长半衰期母核的核素.随着放射性核束技术的发展,基于加速器与在线同位素分离(Isotope Separator On-Line,ISOL)技术的短寿命放射性核束在线穆斯堡尔测量技术也得以发展起来,扩展了穆斯堡尔谱学的应用范围.目前国际上许多加速器(如RIKEN、CERN等)的在线同位素分离装置上都已经建立了在线穆斯堡尔实验装置,并在离子注入、半导体领域取得了成功的应用.本文介绍了在中国原子能科学研究院HI-13串列加速器上尝试建立的用于在线穆斯堡尔谱测量的装置以及初步测量结果.