在束穆斯堡尔实验装置

介绍了最近在兰州重离子加速器上建立的一台在束穆斯堡尔实验装置，讨论了在束穆斯堡尔实验技术。     

用离子注入法制备~(57)Fe穆斯堡尔样品

~(57)Fe是在常温下就能测量穆斯堡尔谱的最常用和方便的同位素之一。应用同位素分离器把~(57)Fe同位素注入待测样品,然后测量样品中~(57)Fe受激发后的内转换电子(或X,γ射线)的穆斯堡尔谱,这是近年来己发展起来的一种新的穆斯堡尔实验技术。由于它可以对不含有穆斯堡尔核素的样品进行所需穆斯堡尔核素的离子注入,并可对样品进行非破坏性测量,从而扩大了穆斯堡尔效应的应用范围。     

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。     

紧凑发射度仪的研制

中国原子能科学研究院的串列加速器升级工程将利用新建的1台100MeV回旋加速器作为驱动加速器，通过新建的在线同位素分离器，在线产生所要求的放射性核束，将其注入HI-13串列加速器中加速后开展各种物理实验研究。其中，在线同位素分离器所产生的放射性核束的强度非常低，     

穆斯堡尔源研制的进展

穆斯堡尔效应是一种原子核无反冲γ射线的共振现象。二十多年来已发展形成一个重要的边缘领域,在许多科学领域和工业技术等方面发挥着引人注目的作用。穆斯堡尔谱学的发展,除了在广度上扩大应用范围外,重要的关键仍在方法上的提高。如何开发和使用更多的穆斯堡尔核素,获得更理想的穆斯堡尔源等仍是人们所关注的问题。制源技术是穆斯堡尔谱学在方法学方面的重要内容之一,它的发展是很快的。最初采用同位素放射源,而后引入     

北京放射性核束装置在线同位素分离器的研制

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,进行在线分析后供物理用户使用,其质量分辨率好于20 000。BRISOL装置现已建成,并开展了氧化镁、氧化钙靶的在线实验,在线产生了³⁷K⁺、³⁸K⁺、²⁰Na⁺、²¹Na⁺等多种放射性核束。本文详细介绍该装置的研制及运行情况。     

北京放射性核束装置在线同位素分离器的研制

北京放射性核束装置在线同位素分离器(BRISOL)采用100 MeV、200μA回旋加速器提供的质子束打靶产生中、短寿命放射性核束,进行在线分析后供物理用户使用,其质量分辨率好于20 000。BRISOL装置现已建成,并开展了氧化镁、氧化钙靶的在线实验,在线产生了~(37)K~+、~(38)K~+、~(20)Na~+、~(21)Na~+等多种放射性核束。本文详细介绍该装置的研制及运行情况。     

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、200μA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~(20)Na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~(20～26)Na~+的钠同位素放射性核束。当质子束流强为8μA时,~(20)Na~+离子束的最大产额为2×10~5 s~(-1),~(21)Na~+离子束的最大产额为4×10~8 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。     

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。     

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。     

Materials science and biophysics applications at the ISOLDE radioactive ion beam facility

The ISOLDE isotope separator facility at CERN provides a variety of radioactive ion beams, currently more than 800 different isotopes from ∼70 chemical elements. The radioisotopes are produced on-line by nuclear reactions from a 1.4 GeV proton beam with various types of targets, outdiffusion of the reaction products and, if possible, chemically selective ionisation, followed by 60 kV acceleration and mass separation. While ISOLDE is mainly used for nuclear and atomic physics studies, applications in materials science and biophysics account for a significant part (currently ∼15%) of the delivered beam time, requested by 18 different experiments. The ISOLDE materials science and biophysics community currently consists of ∼80 scientists from more than 40 participating institutes and 21 countries. In the field of materials science, investigations focus on the study of semiconductors and oxides, with the recent additions of nanoparticles and metals, while the biophysics studies address the toxicity of metal ions in biological systems. The characterisation methods used are typical radioactive probe techniques such as Mössbauer spectroscopy, perturbed angular correlation, emission channeling, and tracer diffusion studies. In addition to these “classic” methods of nuclear solid state physics, also standard semiconductor analysis techniques such as photoluminescence or deep level transient spectroscopy profit from the application of radioactive isotopes, which helps them to overcome their chemical “blindness” since the nuclear half life of radioisotopes provides a signal that changes in time with characteristic exponential decay or saturation curves. In this presentation an overview will be given on the recent research activities in materials science and biophysics at ISOLDE, presenting some of the highlights during the last five years, together with a short outlook on the new developments under way.     

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.     

Development of uranium carbide targets for the on-line production of neutron-rich isotopes

A number of on-line and off-line tests have been performed at the IRIS (investigation of radioactive isotopes at synchrocyclotron) facility in order to develop uranium carbide targets with a high density (11 g/cm³) for the on-line production of neutron-rich isotopes by fission of ²³⁸U. A 1 GeV proton beam was used to bombard two kinds of targets held at temperatures in the range of 1900–2100 °C. The first one was a target-ion source assembly slightly modified to withstand 3 months of continuous heating at a temperature of about 2050 °C. The second unit was of a new kind, where ionisation takes place in the target volume itself. A comparison of the on-line isotopic yields before and after heating for 3 months is here reported. The yields and release times of Rb, Cs and In are compared with the ones obtained from a standard reference target, as measured in previous experiments.     

Present status of singly charged ion ECR sources at the SARA on-line separator

Various 2.45 GHz microwave electron cyclotron resonance (ECR) ion-sources designed with quartz tubes and without hexapole have been developed and tested for production, transport and focalization of singly-charged ions. A first on-line endeavour to separate radioactive isotopes in a He-jet coupled mode has been realized with a capillary skimmer ion-source injection system parallel to the source plasma axis. In order to improve the coupling of a ECR source with the He-jet system, a new compact metallic body ion-source with a skimmer-catcher injection arrangement perpendicular to the plasma has been designed. The layout of this new metallic ion-source is given. The ionization efficiencies have been measured as a function of gas pressure for a complete off-line regime with various support gases and for a dynamical regime induced with an He-jet injection simulating the subsequent on-line coupled mode conditions.     

Method for precision measurement of the masses of short-lived nuclides with application of stable isobars

The distinction of the suggested scheme of the experiment is the application of the isobaric doublets method in determining the masses of short-lived nuclides by means of a high-resolution mass spectrometer. This method enables us to considerably decrease the systematic errors of the measurement results in comparison with the previously applied isotopic reference method.

The work was carried out on an experimental complex, the main component of which was a prism mass spectrometer (PMS) with resolution R = 3 × 10⁴, installed on-line with a mass separator and a synchrocyclotron of the LNPI of the Academy of Sciences of Russia. On this installation we measured the masses of the isotopes ^91–97Rb. Samples containing stable reference isotopes ^91,92,94,96Zr, ⁹³Nb or ^95,97Mo were introduced into the ionizer of the PMS for calibration of the mass scale, that was ensured by their ionization simultaneously with radioactive isotopes of rubidium coming from the mass separator. The values of the masses of the stable isotopes used as reference in the suggested method are known with a very high precision (ΔM/M 3×10⁻⁸), therefore they made a negligible contribution to our experimental errors.     

Ba(Sb0.5In0.5)O3中Sb电子排布的穆斯堡尔研究

用水热合成方法制备了复合钙钛矿结晶Ba(Sb0.5In0.5)O3,并用穆斯堡尔谱学方法配合X射线衍射,研究了其中锑的电子排布。实验结果显示：锑以 5价存在,没有混合价态出现;锑与最近邻氧出现轨道杂化、以共价键结合。     

Dual chamber laser ion source at LISOL

A new type of gas cell for the resonance ionization laser ion source at the Leuven Isotope Separator On Line (LISOL) has been developed and tested under off-line and on-line conditions. Two-step selective laser ionization is applied to produce purified beams of radioactive isotopes. The selectivity of the ion source has been increased by more than one order of magnitude by separation of the stopping and laser ionization regions. This allows the use of electrical fields for further ion purification.     

基于CS-30回旋加速器的同位素研制及应用

简要介绍了四川大学原子核科学技术研究所CS-30加速器的有关情况以及利用该加速器研制和开发同位素的情况。利用该加速器,目前可批量生产¹⁰⁹Cd、⁵⁷Co、²¹¹At、⁹⁸Tc、¹²³I等同位素,并对²¹¹At、¹²³I等核素的应用进行了研究。在完善上述核素制备及应用基础上,还将逐步研究开发⁶²Zn(⁶²Zn-⁶²Cu)、⁶⁴Cu、⁶⁷Cu、⁶⁷Ga、¹⁸F、²⁰¹Tl、⁶⁷Ga和¹¹¹In等核素及其应用,推进加速器生产核素的应用和发展。     

New production systems at ISOLDE

New target systems for the ISOLDE on-line mass separator facility are presented. Targets of carbides, metal/graphite mixtures, foils of refractory metals, molten metals and oxides have been tested. Beams of high intensity of neutron-rich isotopes of a large number of elements are obtained from a uranium carbide target with a hot plasma-discharge ion source. A target of ZrO₂ has been shown to provide high intensity beams of neutron-deficient isotopes of Mn, Cu, Zn, Ga, Ge, As, Se, Br, Kr and Rb, while a SiC target with a hot plasma ion source gives intense beams of radioactive isotopes of a number of light elements. All these systems are rather chemically unselective. Chemically selective performance has been obtained for several systems, i.e.: the production of neutron-deficient Au from (³He, pχn) reactions on a Pt/graphite target with a hot plasma ion source; the production of neutron-deficient Lu and LuF⁺ and Hf and HfF₃⁺ from a Ta-foil target with a hot plasma ion source under CF₄ addition; the production of neutron-deficient Sr as SrF⁺ and Y as YF₂⁺ form a Nb-foil target with a W surface ionizer under CF₄ addition; the production of neutron-deficient Se as COSe⁺ from a ZrO₂ target with a hot plasma ion source under O₂ addition; and the production of radioactive F from a SiC target with a hot plasma ion source operating in Al vapour.     

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.