Status report of the JAERI on-line isotope separator

A mass separator has been connected on line to the 20 MV tandem accelerator at JAERI/Tokai. Using a thermal ion source, decay spectroscopic studies have been carried out for neutron-deficient isotopes in the mass 120–130 region. A study with collinear laser spectroscopy has begun recently. The present paper describes the status of the mass separator facility together with some experimental results.     

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.     

Ion source development for the on-line isotope separator at GSI

The progress in the understanding of ion sources for isotope separation on-line and the feasibility of bunched beams of relatively refractory elements is reported. The ultra-high temperature FEBIAD-H ion source, facilitating the mounting of catchers and window compared to the earlier F-version, enables bunched beams of the elements with adsorption enthalpies up to almost 6 eV, e.g. of Be, Al, Ca, Cr, Fe, Co, Ni, Sr, Pd, Ba, Yb, and Au. This way chemical selectivity for these elements may also be achieved, at least to some extent, for isotopes with halflives 1 min, including especially the difficult separation of alkaline-earth isotopes from isobaric alkalines. These studies also reveal, however, a principal difficulty in the on-line separation of refractory elements, namely their tendency, increasing with ΔH_a, to re-diffuse after release from the catcher into the bulk of the hot source enclosure.     

Status report of the Leuven isotope separator on-line (LISOL)

The mass separator LISOL, on-line to the CYCLONE cyclotron, is described as it is presently configured. The main development has been in the ion-guide operation in conjunction with light-ion induced fusion and fission. The plans to obtain intense (nA) beams of light (A ≤ 30), short-lived nuclei in the framework of the ARENAS³ project are also described.     

兰州在线同位素分离器的FEBIAD源研制

叙述了兰州近代物理研究所的在线同位素分离器FEBIAD源的设计原理、 结构、运行状况及离线和在线调试结果。离线测定Kr和Xe的总效率分别为3．1％和4．5％,^129Xe分辨本领达到360,离子源总离子束流小于10μA。在线测到截面为10^-28cm^2、寿命短至1s的反应产物,在线测出^104In总效率达到1.5%-2%,^104Ag和^104Gd达到1％。     

Energy compensation of an ISOLDE-type isotope separator

The placement of an electric dipole following the magnet in an ISOLDE-type isotope separator can compensate for the energy dispersion introduced by the magnet. This allows the injection into such a separator of ion beams with energy spreads of up to ±3% at mass A = 120, an order of magnitude larger than previously possible. Calculations are presented applying this technique to an IGISOL (ion guide isotope separator on-line) facility, where such energy spreads occur under the conditions where the highest yields are available.     

Elimination of the image curvature in an electromagnetic isotope separator

The elimination of the image curvature in an EMIS with 100 mm long emission slit has been achieved by appropriately curving the emission slit. The straight image allows the design of simpler and more efficient collector pockets.     

An isotope separator for small noble gas samples

A Wien filter isotope enrichment system has been combined with a small turbomolecular pump to form a closed isotope separator for small noble gas samples. Atoms which leave the exit aperture of the plasma discharge ion source without being ionized are circulated back into the source through a feedback line. The system can be operated for several hours in a closed mode to collect up to 50% of the total number of atoms of a selected isotope (e.g. ⁸¹Kr) out of a small gas sample of only 2 × 10⁻³ cm³ STP. Ions are implanted at 10 kV into an aluminized Kapton foil after a flight distance of 150 cm. A beam stabilization system centers the ion beam in two perpendicular directions onto a target aperture to maintain a high enrichment factor of at least 10³ over extended periods of time. Calibration of the enrichment process is achieved by isotope dilution. The system is a key part of the sample processing for ⁸¹Kr and ⁸⁵Kr analysis by laser resonance ionization spectroscopy for applications in isotope geophysics.     

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.     

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.     

CARR堆上在线同位素分离器的离子源

本文介绍在建的中国先进研究堆（China Advanced Research Reactor,CARR）上的在线同位素分离器的三种离子源的原理、结构特点、实验结果。这三种不同的离子源是针对不同的放射性同位素,为了获取理想的束流而研制的。这三种离子源分别是高温表面热电离离子源、弧放电离子源、边引出型潘宁源。其中高温表面热电离离子源内的钨电离器内的温度已达到2400℃,为我们研究难电离的稀土元素提供了保证。     

On the release and ionization efficiency of catcher-ion-source systems in isotope separation on-line

It is shown that the critical steps in isotope separation on-line - diffusion, effusion, and ionization - can be studied in a very efficient way by stimulating the separation process using beam particles of the UNILAC accelerator as tracer instead of reaction products. The analysis of the measured release profiles readily yields the ionization efficiency and the half-life dependence of the separation efficiency on an absolute scale. For the cases in which surface desorption is a fast process compared to solid state diffusion, additionally the decisive delay parameters μ₀ for diffusion and ν for effusion can be extracted. These are closely related to material constants such as diffusion coefficients and enthalpies for surface adsorption and in favourable cases permit extraction of the Arrhenius coefficients. Thus the assumed release model can be tested by comparison with literature values or, in turn, enables the conversion of known material constants into estimates for the half-life dependence of the separation efficiency.

Since ion sources have reached a high degree of sophistication, the ionization efficiency is hardly ever the limiting factor of on-line mass separation. This is in general also true for the diffusion step, if the distribution of the reaction products in the catcher is either homogeneous or very close to the surface. As a consequence it turns out that effusion decisively causes the limitations in mass separation on-line, i.e. surface adsorption for refractory elements and the intrinsic delay for very short half-lives.     

First proof-of-principle experiment with the post-accelerated isotope separator on-line beam at BRIF: measurement of the angular distribution of $$^{23}$$ Na + $$^{40}$$ Ca elastic scattering

Nuclear Science and Techniques - Non-evaporable getter (NEG) films are an integral part of many particle accelerators. These films provide conductance-free evenly distributed pumping, a low thermal...     

The Princeton separator, past and future

Some past research applications of the Princeton separator are reviewed. The future program envisaged includes fundamental β decay studies, low temperature nuclear orientation and nuclear astrophysics.     

Upgrade of the COMPASS tokamak real-time control system

The COMPASS plasma control system is based on the MARTe real-time framework. Thanks to MARTe modularity and flexibility new algorithms have been developed for plasma diagnostic (plasma position calculation), control (shaping field control), and protection systems (central solenoid protection). Moreover, the MARTe framework itself was modified to broaden the communication capabilities via Aurora.This paper presents the recent upgrades and improvements made to the COMPASS real-time plasma control system, focusing on the issues related to precision of the real-time calculations, and discussing the improvements in terms of discharge parameters and stability. In particular, the new real-time system has given the possibility to analyze and to minimize the transport delays of each control loop.     

Upgrade of the RFX-mod real time control system

The real-time control system of RFX-mod, in operation since 2005, has been successful and has allowed several important achievements in the RFX physics research program. As a consequence of this fact, new control algorithms are under investigation, which are more demanding in terms of both enhanced computing power and reduced system latency, currently around 1.5 ms. For this reason, a major upgrade of the system is being considered, and a new architecture has been proposed, taking advantage of the rapid evolution of computer technology in the last years. The central component of the new architecture is a Linux-based multicore server, where individual cores replace the VME computers. The server is connected to the I/O via PCI-e based bus extenders, and every PCI-e connection is managed by a separate core. The system is supervised by MARTe, a software framework for real-time applications written in C++ and developed at JET and currently used for the JET vertical stabilization and in other fusion devices.     

Upgrade issues in FTU control,data acquisition and management

FTU is operating since 1989, thus its hardware and software infrastructure must be continuously updated to preserve its efficiency and reliability. This issue can be addressed by means of two distinct approaches: (i) the migration to an emulated environment enabling the use of modern hardware on virtualized standard servers to keep the operating systems full functionality and the application environment; (ii) the porting of the complete system architecture to new hardware, new operating systems, and new programming languages. This paper reports on the upgrades implemented on FTU in the last two years using both these approaches including the new system to acquire and store the image frames of FTU plasma discharges through a Photron FASTCAM SA4 camera. Regarding data handling, a small Linux high performance computing system (1TFlops) with a high performance data storage system (100 TB) in InfiniBand DDR infrastructure has been installed as data analysis, modelling and archive cluster for the next three years of FTU experimental activities.     

EAST中央控制系统的改造

EAST中央控制系统是EAST实验调度管理的中枢,协调控制各分系统按照预设参数和控制逻辑投入试验,完成EAST装置的各种运行项目。利用PXI总线设备并结合虚拟仪器技术实现的新EAST中央控制系统可很好地完成对各分系统的参数设置和控制,同时升级改造后的网络环境也为实验的稳定运行提供了保障。改造后的EAST中央控制系统已应用于2012年春季EAST放电实验中,运行稳定可靠,取得了良好的控制效果。