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。     

北京在线同位素分离丰中子束流装置关键技术研究进展

正1概述北京在线同位素分离丰中子束流装置(BISOL)是利用中国先进研究堆(CARR)的高通量中子打靶产生的不稳定核素,在电离和质量分析后筛选出的不稳定核束,再经超导后加速器加速至150 MeV/u打靶产生极端丰中子核束的装置。BISOL已于2017年列入国家重大科技基础设施"十三五"规划。     

HI-13串列加速器升级工程：1 用于放射性核束设施驱动加速器的100MeV强流质子回旋加速器

北京放射性核束装置（BRIF）于2004年已在中国原子能科学研究院正式启动。该装置将提供强流质子束和放射性核束（RIB）用于基础和应用研究，如中子物理、核结构、材料科学与生命科学、医用同位素生产等。在该工程中，100MeV强流质子回旋加速器（CYCIAE-100）被选为驱动加速器，它提供能量为75～100MeV、流强为200LIA的质子束。2005年100MeV回旋加速器各系统的初步设计，包括束流动力学、磁铁、高频等都已完成。与回旋加速器设计相关的实验验证工作也已深入展开。     

2 用于放射性核束设施驱动加速器的100MeV强流H^-回旋加速器

北京放射性核束装置，简称为BRIF，是一个新的基于放射性核束装置的加速器工程。该工程由以下几个部分组成：100MeV回旋加速器、在线同位素分离系统、现有的串列加速器注入器改造、超导直线增能器、各种不同的物理实验终端和一个同位素生产研究靶站。作为驱动加速器，100MeV的H^-回旋加速器能够提供75～100MeV、200～500μA以上的质子束流。对于最终能量不高于100MeV，束流强度低于lmA的回旋加速器，选择紧凑型磁铁，采用加速H^-、剥离引出的技术路径，将使得加速器结构更小，也更便宜。     

BISOL相邻两电荷态相同质量重离子束相位能量调节的物理设计

放射性核束物理是国际核物理研究的前沿,滴线区新物理、铁以上重元素的天体合成过程、超重稳定岛核素合成等关键科学问题的突破将对整个自然科学产生重大影响,这些研究都需要高强度的极端丰中子核束。将中国先进研究堆及强流氘离子加速器打靶产生的放射性核束传输至物理终端,采用两电荷态束流同时加速可以有效提高束流强度;通过分析离子束分离注入同步加速原理,采用静电高压调节离子束相位差,速率调节器同步离子束能量,分别计算得到不同种类核束引出电压参数和速率同步参数;同时分析计算了电压调节与离子束相位差变化关系,得到电压调节参数。计算结果表明,当调节电压幅值取±8 k V时,可满足不同种类离子相位调节需求。     

用于放射性核束设施驱动加速器的100 MeV强流质子回旋加速器

北京放射性核束装置(BRIF)于2004年已在中国原子能科学研究院正式启动。该装置将提供强流质子束和放射性核束(RIB)用于基础和应用研究,如中子物理、核结构、材料科学与生命科学、医用同位素生产等。在该工程中,100MeV强流质子回旋加速器(CYCIAE-100)被选为驱动加速器,它提供能量为75～100MeV、流强为200μA的质子束。2005年100MeV回旋加速器各系统的初步设计,包括束流动力学、磁铁、高频等都已完成。与回旋加速器设计相关的实验验证工作也已深入展开。选择紧凑型磁铁结构,采用加速H-、剥离引出的技术路线,将使得加速器体积小、造价…     

4 ADS次临界实验装置——启明星1#

加速器驱动的次临界系统（ADS）是嬗变放射性核废物、有效利用核资源及产生核能的装置。该系统包括中能强流质子加速器、外源中子产生器和次临界反应堆。当加速器加速的高能质子轰击重金属靶（如铅）时，与重金属靶核发生散裂反应，一个质子引起的散裂反应可产生几十个中子，用散裂产生的中子作为中子源作用于次临界反应堆上，次临界反应堆发生并维持链式反应，在一定功率下运行。因此，ADS概念一经提出就受到极大关注，被世界核能界公认为是目前解决大量放射性废物，降低深埋储藏风险的最具潜力的工具。     

双漂移谐波聚束器的物理设计

为了满足北京放射性核束装置计划中超导直线助能器对ＨＩ－１３串列加速器束流脉冲化系统的要求，同时兼顾目前快中子飞行时间测量实验的需要，进行了双漂移谐波聚束器的物理设计。聚束器基频为６ＭＨｚ，可以对质子、氘直至铯等所有离子束进行脉冲聚束，束流利用效率可达５０％—６０％，质子等轻离子脉冲束的脉冲时间宽度小于１ｎｓ。设计中分析了串列加速器束流传输系统中影响脉冲束流性能的各主要因素，通过束流纵向相空间的传输模拟计算，获得了满意的结果。     

BRISOL钠同位素放射性核束的产生

北京放射性核束装置在线同位素分离器（BRISOL）采用100 MeV、200 μA回旋加速器提供的质子束打靶产生中、短寿命放射性核束，在线分析后供物理用户使用，其质量分辨率好于20 000。为开展²⁰Na核的奇异衰变特性研究，研制了氧化镁靶，并采用100 MeV质子束轰击氧化镁靶在线产生了^20～26Na⁺的钠同位素放射性核束。当质子束流强为8 μA时，²⁰Na⁺离子束的最大产额为2×10⁵ s^-1，²¹Na⁺离子束的最大产额为4×10⁸ s^-1。完成了北京放射性核束装置首个放射性核束物理实验，累计供束近200 h。     

在强流周期聚焦传输网络中填充因子对K-V分布束晕控制效果的影响

强流离子加速器在核废料处理、氚的生产、核嬗变、洁净核能生产等方面有着重要的应用。由于离子束在加速器通道中运动时有束晕产生,导致放射性超标、束流损失等不利影响,因此,应用时必须解决好束晕-混沌问题。国内外已对这一问题进行研究。我们课题组已提出一些有效控制束晕-混     

Targets and ion sources at the TISOL facility

The TISOL thick target, on-line isotope separator is now operational at the TRIUMF facility with an active experimental program. A series of newly developed, target materials coupled with two different ion sources can now produce a wide range of isotopes. Radioactive beams of isotopes of He, C, N, O, Ne, Cl, Ar, Kr and Xe are now available in significant amounts from the first ECR (electron cyclotron resonance) ion source directly coupled to a multipurpose ISOL device. In addition, a surface ionization source with good yields for radioactive isotopes of Li, Na, Al, Ga, Rb, In, Cs, Yb and Fr is also available. Special emphasis has been given to the development of target materials, in particular light mass powder or pellet targets such as SiC and MgO. In addition, a newly developed zeolite (NaSiAlO₄) target shows properties which make it an optimal choice for producing isotopes near stability for nuclear astrophysics experiments with accelerated radioactive beams. Source and target developments at the upgraded TISOL facility will be presented.     

BRISOL钾同位素放射性核束的产生

北京放射性核束装置在线同位素分离器（BRISOL）采用一台100 MeV回旋加速器提供的最大200 μA的质子束打靶在线产生放射性核束,其最高质量分辨率好于20 000。2015年,BRISOL装置建成并使用05 μA质子束轰击氧化钙靶产生了37K+、38K+放射性核束,其中38K+的产额为1×106 pps。为了提高氧化钙靶产生钾放射性核束的产额以满足物理用户需求,BRISOL于近期开展了氧化钙靶的在线实验。实验中使用氧化钙靶产生了36～38K+、43K+、45～47K+等多种放射性核束,同时将38K+的最大产额提高到了112×1010 pps。本文详细介绍氧化钙靶的研制及在线实验结果。     

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.     

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。     

An ISOSPIN laboratory for North America

Over the last 18 months interest has grown significantly in North America in the installation of an accelerated radioactive beams facility of the ISOL/post-accelerator approach. Sparked by the recent workshop on the Science of Intense Radioactive Beams held at Los Alamos in 1990, a steering committee was established to assist the preparation of a proposal for such a facility, to develop a User's group, to assess the quality of the possible scientific program, and to encourage a national laboratory with the appropriate infrastructure to play a major role in the building of the Isospin Laboratory (ISL). A white paper summarizing the scientific program and a conceptual layout of a BenchMark Facility (BMF) for ISL to match the perceived needs of this program is being prepared to stimulate further support in the community. BMF will be based primarily on technology available today or that which can be reasonably extrapolated from known technology to illustrate the feasibility of the concepts.     

Two-plane painting injection scheme for BRing of HIAF

The high-intensity heavy-ion accelerator facility(HIAF)is under design at the Institute of Modern Physics(IMP)and will provide an intense ion beam for nuclear physics,atomic mass measurement research,and other applications.As the main ring of HIAF,the BRing accumulates beams to high intensity and accelerates them to high energy.To achieve high intensities up to 1×10~(11)(~(238)U~(34+)),the injection gain of the BRing must be as high as 88.However,multiple multiturn injection supported by the electron cooling system takes a long time,causing substantial beam loss under a strong space charge effect.Hence,a two-plane painting injection scheme is proposed for beam accumulation in the BRing.This scheme uses a tilted injection septum and horizontal and vertical bump magnets to paint the beam into horizontal and vertical phase space simultaneously.In this paper,the two-plane painting injection parameters are optimized,and the resulting injection process is simulated using the Objective Ring Beam Injection and Tracking(ORBIT)code.An injection gain of up to 110.3 with a loss rate of 2:3%is achieved,meeting the requirements of BRing.     

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。     

Dependence of exotic nuclides production on target and beam features

With regard to the ISOL technique, the dependence of intermediate mass (80–160A) production on target and proton beam features has been investigated by means of hadronic transport Monte Carlo codes. The analysis of the target material (mechanism of production), dimensions (length and width) and composition as well as the proton beam energy has shown that in principle, regardless of technological difficulties, the production of neutron-rich isotopes of intermediate mass (80–160 A) can be successfully achieved with proton beams of low-medium energy into uranium thick targets. The power density in uranium targets bombarded by low-medium energy protons has been analyzed too.     

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.     

In beam nuclear polarization of on-line separated isotopes

Dynamical nuclear polarization techniques are newly being applied at the Leuven Isotope Separator On-Line of the Cyclotron Research Center in Louvain-la-Neuve to polarize the intense radioactive ion beams which have become available. The experimental setup is described and first results are reported.