The REX-ISOLDE project

The Radioactive Beam Experiment REX-ISOLDE [1–3] is a pilot experiment at ISOLDE (CERN) testing the new concept of post acceleration of radioactive ion beams by using charge breeding of the ions in a high charge state ion source and the efficient acceleration of the highly charged ions in a short LINAC using modern ion accelerator structures. In order to prepare the ions for the experiments singly charged radioactive ions from the on-line mass separator ISOLDE will be cooled and bunched in a Penning trap, charge bred in an electron beam ion source (EBIS) and finally accelerated in the LINAC. The LINAC consists of a radiofrequency quadrupole (RFQ) accelerator, which accelerates the ions up to 0.3 MeV/u, an interdigital H-type (IH) structure with a final energy between 1.1 and 1.2 MeV/u and three seven gap resonators, which allow the variation of the final energy. With an energy of the radioactive beams between 0.8 MeV/u and 2.2 MeV/u a wide range of experiments in the field of nuclear spectroscopy, astrophysics and solid state physics will be addressed by REX-ISOLDE. This revised version was published online in July 2006 with corrections to the Cover Date.     

β-NMR

The β-NMR facility at ISAC is constructed specifically for experiments in condensed matter physics with radioactive ion beams. Using co-linear optical pumping, a ⁸Li^?+? ion beam having a large nuclear spin polarisation and low energy (nominally 30 keV) can be generated. When implanted into materials these ions penetrate to shallow depths comparable to length scales of interest in the physics of surfaces and interfaces between materials. Such low-energy ions can be decelerated with simple electrostatic optics to enable depth-resolved studies of near-surface phenomena over the range of about 2–200 nm. Since the β-NMR signal is extracted from the asymmetry intrinsic to beta-decay and therefore monitors the polarisation of the radioactive probe nuclear magnetic moments, this technique is fundamentally a probe of local magnetism. More generally though, any phenomena which affects the polarisation of the implanted spins by, for example, a change in resonance frequency, line width or relaxation rate can be studied. The β-NMR program at ISAC currently supports a number of experiments in magnetism and superconductivity as well as novel ultra-thin heterostructures exhibiting properties that cannot occur in bulk materials. The general purpose zero/low field and high field spectrometers are configured to perform CW and pulsed RF nuclear magnetic resonance and spin relaxation experiments over a range of temperatures (3–300 K) and magnetic fields (0–9 T).     

CERN的ISOLDE装置上的ECR离子剥离器Phoenix的最新进展

At ISOLDE (CERN),an on-line test bench is dedicated to charge breeding experiments with a 14GHz Phoenix ion source,for the investigation of the 1 →n scenario at next generation ISOL-type facilities.This year,various technical developments have been undertaken for intensifying the tests of the on- line performances of the booster with a high diversity of stable and radioactive ion beams.This contribution will present an overview of the latest developments,the current challenges,and some perspectives for the future use of the Phoenix booster for physics experiments at ISOLDE.     

放射性束在固体物理和材料科学中的应用

回顾了放射性核素在固体物理和材料科学中的应用,并对高能放射性束流的应用前景作了展望．The application of radioactive isotopes to solid state physics and material science is reviewed and the perspectives with high energy radioactive ion beams are discussed.     

Mössbauer spectroscopy at ISOLDE

Applications of radioactive ion beams produced at the ISOLDE facility for Mössbauer studies of probe atoms in solids are presented. Examples are given for a site-selective incorporation on different substitutional sites in compound semiconductors by ion implantation and thermal annealing of the radiation damage resulting from the implantation. The interactions of the probe atoms with lattice defects created in the implantation process have been studied to elucidate likely causes for the site-selective implantation mechanism. The technique has enabled to determine the electronic densities at electrically active substitutional probe atoms, having shallow donor or acceptor states as well as states deeper in the band gap. The results are in good agreement with theoretical results from local density calculations. Methodological aspects of the Mössbauer emission techniques employed at ISOLDE are compared to alternative accelerator based techniques and the consequences of the application of different precursor isotopes to the ⁵⁷Fe Mössbauer isotope are treated in detail for ⁵⁷Fe in silicon. Finally, results obtained for the magnetic hyperfine interactions of 5 sp impurities associated with vacancies in ferromagnetic metals are discussed.     

Bright perspectives for nuclear photonics

With the advent of new high-power, short-pulse laser facilities in combination with novel technologies for the production of highly brilliant, intense γ beams (like, e.g., Extreme Light Infrastructure – Nuclear Physics (ELI-NP) in Bucharest, MEGaRay in Livermore or a planned upgrade of the HIγS facility at Duke University), unprecedented perspectives will open up in the coming years for photonuclear physics both in basic sciences as in various fields of applications. Ultra-high sensitivity will be enabled by an envisaged increase of the γ-beam spectral density from the presently typical 10²γ/eVs to about 10⁴γ/eVs, thus enabling a new quality of nuclear photonics [1], assisted by new γ-optical elements [2]. Photonuclear reactions with highly brilliant γ beams will allow to produce radioisotopes for nuclear medicine with much higher specific activity and/or more economically than with conventional methods. This will open the door for completely new clinical applications of radioisotopes [3]. The isotopic, state-selective sensitivity of the well-established technique of nuclear resonance fluorescence (NRF) will be boosted by the drastically reduced energy bandwidth (<0.1%) of the novel γ beams. Together with a much higher intensity of these beams, this will pave the road towards a γ-beam based non-invasive tomography and microscopy, assisting the management of nuclear materials, such as radioactive waste management, the detection of nuclear fissile material in the recycling process or the detection of clandestine fissile materials. Moreover, also secondary sources like low-energy, pulsed, polarized neutron beams of high intensity and high brilliance [4] or a new type of positron source with significantly increased brilliance, for the first time fully polarized [5], can be realized and lead to new applications in solid state physics or material sciences.     

First $\gamma$-rays from radioactive beams at REX-ISOLDE

In order to demonstrate a novel scheme to accelerate radioactive ions and to provide radioactive ion beams for physics experiments, the radioactive beam experiment (REX) was installed at ISOLDE, CERN. One of the main experimental devices that will use these beams is the newly commissioned HPGe array MINIBALL featuring an excellent granularity, energy resolution, and rate capability. First experiments have been performed using beams of neutron-rich Na and Mg isotopes.Received: 8 November 2002, Published online: 24 February 2004PACS: 41.75.Lx Other advanced accelerator concepts - 29.30.Kv X- and -ray spectroscopy - 25.60.Je Transfer reactionsH. Scheit: For the REX-ISOLDE-MINIBALL Collaboration     

核物理与工农业发展

核物理应用主要包括核分析技术、同位素技术和离子束技术的应用,这些应用在工农业生产中发挥着巨大作用.离子束、电子束和同位素辐射源被广泛应用于辐照探伤、辐照加工、辐照消毒、辐照育种、辐照杀虫、辐照保藏等方面.核物理应用新技术将成为人类生活中重要的组成部分,正确认识核辐射并掌握基本的辐射防护知识具有重要意义.文章介绍了核物理在工业和农业中的应用及其社会效益和经济效益.     

Computer Simulation of High Power Ion Beams Interaction with Matter

When high-power ion beams (HPIB) collides with matter, it generates plasma with parameters of a wide range, staring with those well mastered in physics and gas discharge technologies and ending with those appropriate to such natural systems as star nucleus and thermonuclear systems in feasible power projects based on the controlled inertial thermonuclear synthesis. We are interested in a fairly wide range of beam power densities (from 1 GW/cm² to 10 TW/cm²). This paper describes one mathematical model in one dimension (a plane geometry is assumed) and one model in two dimensions (r- and z-coordinates). The models are completed by wide- range equations of state for real matter (construction materials) and supplemented with additional equations describing rheological, thermophysical, and optical properties of solid media under consideration (in various phase states from solid to plasma, including states of a strongly nonideal plasma). On the base of the continual approach, mechanical destruction of materials due to tensile strain generated by rarefaction waves is taken into account. In modeling the action of ion beams of moderate intensity (I < 10 GW/cm²) on metal targets, elastoplastic properties are taken into account, and in describing the action of ion beams with intensities I > 10 GW/cm² (in the two- dimensional model based on the large-particle technique) heat transfer, including radiational processes, is considered. Opportunities offered by contemporary computer simulation techniques in the field of interaction between HPIB and matter are demonstrated, in particular, a possibility of simulating hypervelocity impact with the help of HPIB has been shown and the necessary conditions have been determined. The results of our computer simulation may be interesting from the viewpoint of some technological applications of HPIB, for example, pulsed destruction and strengthening of construction materials, pulsed ion implantation and etc. [1].     

Experiments with intense secondary beams of radioactive ions

Electromagnetic mass separation applied on-line to accelerators and nuclear reactors is now a standard technique for producing preselected isotopic beams (A, Z selection) of nuclear reaction products. The development, performance and anatomy of a large on-line isotope separator facility, the CERN-ISOLDE, is discussed. As a result of recent technical developments it is now possible to study individual nuclei of about 40 elements, in many cases out to where the limits of nucleon binding are approached and half-lives become as short as 10 ms. It is shown that the nuclear reaction processes induced with the high-intensity several hundred MeV proton beam can provide secondary radioactive beams in almost all regions of the nuclidic chart with intensities which are not matched by any other method. The intense beams of 10⁸–10¹¹ atoms/s have opened up a number of new experimental possibilities like laser spectroscopy on radioactive atoms, radioactive targets for nuclear reaction spectroscopy, and precision X-ray shift measurements.     

Space-Charge Effects with REXTRAP

The beam quality of radioactive ion beams produced by present target ion source technology is often not sufficient for direct post-acceleration. Furthermore, pulsed beams insure a more efficient use of an accelerator. In the case of REX-ISOLDE, the post accelerator at the CERN ISOLDE facility, a gas-filled Penning trap (REXTRAP) has been chosen for accumulation of the radioactive ions and conversion into cooled bunches. Radial centering of the ions is achieved by applying an rf field with a frequency equal to the cyclotron frequency of the desired ion species. The efficiency achieved in the first tests with different isotopes covering nearly the entire mass range was already >20%. Going to total numbers of >10⁵ stored ions in the trap a shift of the centering frequency could be observed, which is most likely due to space charge effects. Despite this, it was possible to accumulate up to 10⁷ ions and deliver them as cooled bunches. This revised version was published online in July 2006 with corrections to the Cover Date.     

Rare isotope beams at ISAC—target & ion source systems

The present status of the ISAC facility for rare isotopes beams after its first 10 years of operation is presented. Planning for the ISAC facility started in 1985 with the Parksville workshop on radioactive ion beams (Buchmann and D’Auria 1985). It was put on halt by the KAON proposal and planning was only resumed in 1993 after the cancellation of KAON. The ISAC facility was built to satisfy the scientific need for accelerated beams of rare isotopes for use in applications such as nuclear physics, nuclear astrophysics, atomic and condensed matter physics as well as medicine. At the time of the ISAC proposal submission, a number of facilities were either planned or under construction. In order to have an impact in the field, the requirements and specifications for the driver beam intensity on target was set to 100 μA, 500 MeV protons, which for ISAC results in a driver beam power of 50 kW.     

核物理研究新进展

本文介绍了国际核物理研究的趋势,核物理研究的前沿已从传统核物理转向亚核自由度变得重要的领域,讨论了在核结构、核反应、相对论性重离子碰撞、亚核自由度、放射性核束和核天体物理学等领域所获得的最新成果. It is presented the trend of the nuclear physics research in the world,the fron- tier of nuclear physics research has been moved from the traditional nuclear physics to the field in which the subnuclear freedoms become very important.New research results obtained in the fields of nuclear structures,nuclear reactions,relativistic heavy ion collisions, subnuclear freedoms,radioactive nuclear beams and nuclear astrophysics are discussed.     

Nuclear Few-Body Physics at FAIR

The FAIR facility, to be constructed at the GSI site in Darmstadt, will be addressing a wealth of outstanding questions within the realm of subatomic, atomic and plasma physics through a combination of novel accelerators, storage rings and innovative experimental set-ups. One of the key installations is the fragment separator Super-FRS that will be able to deliver an unprecedented range of radioactive ion beams (RIBs) in the energy range of 0?C1.5?GeV/u to the envisaged experiments collected within the NuSTAR collaboration. This will in particular permit new experimental investigations of nuclear few-body systems at extreme isospins, also reaching beyond the drip-lines, using the NuSTAR-R³B set-up. The outcome of pilot experiments on unbound systems are reported, as well as crucial detector upgrades.     

Reaction mechanisms for light halo nuclei

Current nuclear physics focuses on exploring nucleon matter under extreme conditions, such as those that can be created in modern accelerator laboratories. On the neutron-rich side of stability, radioactive beams have already led to the discovery of halos in nuclei with neutron distributions extending to large distances. Halo nuclei are composite systems with prominent features of few-body correlations, which reveal themselves in various reactions involving these systems. We will discuss experiments that probe a halo structure through studying various reactions involving halo nuclei, with special emphasis on how, from the theoretical point of view, such reactions contribute to our knowledge of the structure and dynamics of the nuclear halo.     

Synthesis and decay properties of superheavy atoms in nuclear reactions induced by stable and radioactive ion beams

This talk consists of two parts. The first one presents the results of investigations performed in 1998-2000 in Dubna on the synthesis of superheavy nuclei in reactions induced by ⁴⁸Ca ions. The radioactive decay properties of the nuclei, indicating a considerable increase in the α-decay and spontaneous fission half-lives of the isotopes of elements 110-116 when approaching the closed neutron shell at N = 184, are given. In the second part the possible ways of advancing into the region of more neutron-rich nuclei, using stable and radioactive ion beams, are discussed. Since so far no intense radioactive ion beams are available, some experiments with stable beams are considered as a test for the suggested ideas. Received: 1 May 2001 / Accepted: 4 December 2001     

Spin-polarization of radioactive 123Ing.s. by the tilted-foil method

A spin-polarized radioactive ¹²³In (I ^π , g = 1.220(2) , T _1/2 = 5.97(5) s) beam has been successfully generated by the tilted-foil method. This nuclide is the heaviest ever polarized in its ground state by this method. Using the ISOL-based re-acceleration-type facility TRIAC, an ¹²³In_g.s. beam of 305 keV/nucleon went through a stack of 15 carbon foils with a tilt angle of 70^° , and an asymmetry of 0.76 ± 0.25% of β-decays was observed by the β-NMR technique. The asymmetry shows that the tilted-foil method combined with a re-acceleration facility is useful for producing spin-polarized beams for applications such as nuclear physics and materials science.     

Solid‐State NMR Studies of Pharmaceutical Systems

Abstract

High‐and low‐resolution solid‐state nuclear magnetic resonance (SSNMR) applications to the study of pharmaceuticals are reviewed. Examples are shown involving the use of mono‐and bidimensional SSNMR techniques based on different nuclear interactions and the measurement of several nuclear parameters, such as chemical shifts, line widths, and relaxation times (T₁, T₂, T_1ρ). The systems investigated include pure active pharmaceutical ingredients (APIs), substances used as drug excipients, and solid dispersions formed by APIs and excipients, up to final drug formulations. The most important aspects treated concern structural, dynamic, and morphological properties, and, in particular, identification, characterization, and quantitation of polymorphs and related forms, conformational and crystalline packing behavior, amorphous phase properties and stability, effects of drug processing, molecular motions, API‐excipient and excipient‐excipient chemical and physical interactions, and phase mixing in heterophasic systems.     

Physics of radioactive nuclear beams: Theoretical perspective

One of the main frontiers of nuclear structure today is the physics of radioactive nuclear beams. Thanks to developments in experimental technology, we are on the verge of invading new territory of extremeN/Z ratios in an unprecedented way. Experiments with radioactive beams will make it possible to look closely into many aspects of the nuclear many-body problem. What makes this subject both exciting and difficult is: (i) the weak binding and corresponding closeness of the particle continuum, implying a large diffuseness of the nuclear surface and extreme spatial dimensions characterizing the outermost nucleons, and (ii) access to the exotic combinations of proton and neutron numbers which offers prospects for completely new structural phenomena.     

Particle accelerator physics and technology for high energy density physics research

Interaction phenomena of intense ion- and laser radiation with matter have a large range of application in different fields of science, extending from basic research of plasma properties to applications in energy science, especially in inertial fusion. The heavy ion synchrotron at GSI now routinely delivers intense uranium beams that deposit about 1 kJ/g of specific energy in solid matter, e.g. solid lead. Our simulations show that the new accelerator complex FAIR (Facility for Antiproton and Ion Research) at GSI as well as beams from the CERN large hadron collider (LHC) will vastly extend the accessible parameter range for high energy density states. A natural example of hot dense plasma is provided by our neighbouring star the sun, and allows a deep insight into the physics of fusion, the properties of matter at high energy density, and is moreover an excellent laboratory for astroparticle physics. As such the sun's interior plasma can even be used to probe the existence of novel particles and dark matter candidates. We present an overview on recent results and developments of dense plasma physics addressed with heavy ion and laser beams combined with accelerator- and nuclear physics technology.