Table of contents

This volume contains the Proceedings of the 13th International Conference on the Physics of Highly Charged Ions (HCI2006) held at Queen's University Belfast, Northern Ireland from 28 August to 1 September 2006. The conference was organized by a local committee consisting of academic staff from the School of Mathematics and Physics at Queen's University Belfast together with colleagues from the physics departments of University College Dublin and Dublin City University in the Republic of Ireland. This conference series began in Stockholm in 1982 and since then has been held every two years at different venues around the world. Following Stockholm the conference was held in Oxford (UK) in 1984, Groningen (Netherlands) in 1986, Grenoble (France) in 1988, Giessen (Germany) in 1990, Manhattan (USA) in 1992, Vienna (Austria) in 1994, Omiya (Japan) in 1996, Bensheim (Germany) 1998, Berkeley (USA) 2000, Caen (France) in 2002, Vilnius (Lithuania) in 2004 and Belfast (UK) in 2006.

Highly charged ion physics touches on a wide range of other disciplines as the HCI2006 conference and these proceedings amply testify. Furthermore, this subject is vibrant and continuing to expand its spheres of influence. It is both helping to deliver new technological applications and also fundamental insights into the workings of our universe. Progress in high precision fundamental measurements has informed many body quantum dynamics, quantum electrodynamics, the search for physics beyond the standard model and the determination of nuclear properties; all are reported in these proceedings. Highly charged ions however don't only inform our basic view of the universe at small scale. Understanding of their interactions with other forms of matter is essential to understand many astrophysical environments. They also play a key role in future fusion reactors, with similar interactions and processes being of importance, along with others, particularly those relating to impact on surfaces also being important. Hence they are of direct relevance to one of the major hopes for servicing our long-term energy requirements. Again recent progress in these areas can be found in these proceedings.

When viewed in terms of orders of magnitude, life, of course, occupies the middle ground between sub-atomic and astronomical distance scales. Here highly charged ions are finding new applications, both in terms of quality of life and also our understanding of it. In terms of quality of life, in addition to the role they will play in future energy reactors, these ions can contribute to new means of fabrication currently being developed to make the electronic devices of the future. Furthermore they are used for various medical procedures, mostly concerned with radiotherapy, thereby acting to save life. Finally they continue to inform our understanding of the fundamentals of life as they are increasingly being used in life-science research techniques. Again recent developments in all these areas were discussed at HCI2006 and are reported in these proceedings.

The HCI2006 local committee organized, with the help of the International Advisory Board, a programme which we hope reflected the breadth and current status of the field of highly charged ion physics and our programme had eight review lectures, ten progress reports and twentyfour talks which were selected from the contributed papers. The Book of Abstracts was edited by members of the local committee, John Costello (DCU), Gleb Gribakin (QUB), Penny Scott (QUB) and Emma Sokell (UCD). Two poster sessions were held having a total of 149 posters. Prizes were awarded by the Journal of Physics B: Atomic, Molecular and Optical Physics (Institute of Physics Publishing) to the best posters presented by postgraduate students. The posters were judged by attending members of The International Advisory Board and were won by Birgit Schabinger (University of Mainz, Germany), Beatte Solleder (Vienna University of Technology, Austria), Sergy Trotsenko (GSI, Germany) and Martin Andersson (University of Lund, Sweden).

The conference had over 200 participants from 21 countries around the world. Almost a quarter of the delegates were postgraduate students which is a testament to interest this field generates in young physicists.

These proceedings contain a total of 104 papers with the invited papers and progress reports followed by contributed papers grouped into the 5 categories of: (1) Fundamental aspects, structure and spectroscopy; (2) Collisions with electrons, ions, atoms and molecules; (3) Interactions with clusters, surfaces and solids; (4) Interactions with photons, plasmas and strong field processes, and (5) Production, experimental developments and applications. The papers were refereed by senior delegates to the conference with two referees allocated to each paper. Papers were refereed at the conference with authors asked to return their revised manuscripts within two weeks of the end of the conference. Invited papers were allocated a maximum of eight pages, progress reports six pages and contributed papers 4 pages. We thank all of the referees for their rapid response and comments and the authors for enabling these proceedings to be published in a relatively short time after the conference. Please note that due to an oversight the invited paper `The potential of highly charged ions: possible future applications' by J D Gillaspy, J M Pomeroy, A C Perrella and H Grube, appears at the end of this volume, and we apologise to the authors.

Acknowledgements

We wish to thank the International Fund for Ireland in providing financial support for this conference. The assistance of the Belfast Visitor and Convention Bureau and the Northern Ireland Tourist Board are particularly acknowledged. The Lord Mayor and City Council of Belfast are thanked for the welcome reception at the City Hall and for the use of the Banqueting Hall. We also thank Journal of Physics B for their sponsorship of the student poster prizes. Our colleagues on the local organizing committee are thanked for their help in putting together the programme and in the day to day running of the conference. Particular thanks are due to the postgraduate students from the School of Mathematics and Physics who operated the audio-visual equipment and ran the conference office. The contribution of Wendy Rutherford to the organization of this conference and the assistance of Kevin Dunseath in the preparation of the Book of Abstracts is gratefully acknowledged.

(The PDF file also contains a list of Committees, Sponsors and Exhibitors)

R W McCullough, F J Currell, J Greenwood, G Gribakin and M P Scott Editors School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, Northern Ireland, UK

It was with great sadness that we learnt of the death of colleague and friend Professor Hannspeter Winter in Vienna on the 8 November 2006. In memory of him and the contribution he made both to our conference and to the field of the physics of highly charged ions we dedicate these proceedings. Hannspeter was one of our distinguished invited speakers at HCI2006 and gave a talk on the status of the ITER programme. His invited paper on the subject is included in these proceedings.

Hannspeter will be particularly remembered for his pioneering work on ion-surface interactions that, together with his colleagues at the Vienna University of Technology (TUW), has stimulated a worldwide experimental and theoretical interest in this field. He was appointed Director of the Institut fuer Allgemeine Physik at TUW in 1987 and using both his scientific and management skills has made it one of the leading university physics laboratories in the world. His research publications, of which there are 270, have inspired many others to work in the field of atomic and plasma physics. He was also a great European playing a major role in the EURATOM fusion programme, the European Physical Society and the International Union of Pure and Applied Physics and was an evaluator and advisory board member for many national and international institutions.

Hannspeter was also an interesting and friendly social companion with interests in current affairs, music and fine wines and will be greatly missed both on a scientific and social level. Our condolences go to his wife Renate, son Dorian and his relatives.

R W McCullough Co-chair HCI2006

Following the pioneering experiment of Dolder, Harrison and Smith nearly a half-century ago, measurements based on the colliding-beams technique became a major source of fundamental data on the electronic structure and interactions of ions. The subsequent development of powerful new sources of highly charged ions and large-scale national facilities such as heavy-ion storage rings and synchrotron light sources provided new applications for established techniques and inspired the development of new interacting-beams methods to take advantage of their unique capabilities. This paper focuses on experimental developments within the last decade involving multiply charged ions using crossed, inclined and merged beams. Examples are presented to highlight such experiments and their impact on our knowledge of the atomic structure of multiply charged ions as well as their interactions in plasmas. Atomic processes considered are elastic scattering, excitation, ionisation, recombination and electron transfer.

Trapping and cooling techniques have become very important for many fundamental experiments in atomic physics. When applied to highly charged ions confined in Penning traps, these procedures are very effective for testing quantum electrodynamics in extreme electromagnetic fields produced by heavy highly charged ions such as uranium U⁹¹⁺. In addition, fundamental constants or nuclear ground state properties can be determined with high accuracy in these simple systems. Finally, by studying a single trapped radioactive ion, its nuclear decay can be studied in detail by observing the disappearance of the signal of the mother and the appearance of that of the daughter isotope. Such experiments on highly charged ions at extremely low energy will become possible by the HITRAP facility which is currently being built up at GSI. Also the future Facility for Antiproton and Ion Research (FAIR) will be briefly described which is expected to be operational by 2014.

Electrostatic storage rings are suitable for storing macromolecules, such as biomolecules. The combination of electrostatic storage rings and electron targets opens up a new aspect for studying electron-biomolecular ion collisions with well-defined energies in the gas-phase. Neutral-particle emissions in collisions of electrons with biomolecular ions, studied by the electrostatic storage rings with the electron targets, are reviewed. In electronbiomolecular anion collisions, high threshold energies for producing neutrals are a common remarkable feature. Meanwhile, in electron-biomolecular cation collisions, resonant neutral particle emissions were observed in some specific ions and at particular energies. The origins of these phenomena are discussed based on well-known concepts in physics, chemistry and biology.

We review recent experimental and theoretical progress made in the scope of swift highly charged ion channelling in crystals. The usefulness of such studies is their ability to yield impact parameter information on charge transfer processes, and also on some time related problems. We discuss the cooling and heating phenomena at MeV/u energies, results obtained with decelerated H-like ion beams at GSI and with ions having an excess of electrons at GANIL, the superdensity effect along atomic strings and Resonant Coherent Excitation.

Thermonuclear fusion powers our universe and is a most promising option for electricity and hydrogen fuel generation within a future sustainable and environmentally benign energy scenario. We shortly describe the current status of magnetic fusion research on its way to the international tokamak experiment ITER, for which construction at the European site Cadarache (France) starts in the near future and first plasma operation is expected in about ten years from now. In the adopted EU strategy for international fusion R&D, ITER is the first part of a 'broader approach to fusion' toward a fusion demonstration reactor ('DEMO') which can supply electricity into a power grid before the mid of this century. We then discuss the role of highly charged ions (HCI) for magnetic fusion (plasma transport, heating, edge and divertor plasmas, and diagnostics). Finally, we present two illustrative examples from our own work on HCI atomic and surface collisions with relevance for magnetic fusion plasmas.

Attainment of tunable laser-like radiation in the VUV and X-ray spectral regions is becoming a reality with the construction of single-pass Free Electron Lasers (FELs) based on the principle of Self-Amplified Spontaneous Emission (SASE). The paper introduces the development of short wavelength sources from an atomic physics perspective, describes the SASE FEL process and discusses examples from first user experiments at FLASH (Free Electron Laser at DESY (Hamburg). The perspective for further progress to shorter wavelength devices is outlined.

Single ionization of simple molecules, e.g. H₂, CO₂, by fast charged particle impact has been studied using a reaction microscope. By measuring the momenta of the emitted electron and the recoil ionic fragment in coincidence, channel-selective low-energy electron spectra have been recorded. The experimental cross sections will be presented, compared with the predictions of state-of-the-art CDW-EIS calculations and discussed in terms of molecular effects such as (i) autoionization and predissociation channels, (ii) interference patterns resulting from the two-center geometry of the diatomic molecule, in analogy to Young's double-slit experiment and (iii) dependence of the electron emission on the orientation of the molecular axis.

HIRFL-CSR, a new cooler-storage-ring project, is the post-acceleration system of the Heavy Ion Research Facility in Lanzhou (HIRFL) consisting of a main ring (CSRm) and an experimental ring (CSRe). The construction of the HIRFL-CSR complex is nearing completion. The stored beam in the CSRm has been observed. Recently, the stored beam was accelerated from 7 MeV/u to 30 MeV/u. The cluster target is located in one straight section of the CSRe providing cluster jet targets of inert gases and small molecular gases. The cluster target has been finished and the results of the test running are presented.

The Gray Cancer Institute is one of a small number of laboratories worldwide routinely using particle microbeam techniques for radiobiological applications. Cellular micro-irradiation methods have been used to provide experimental opportunities not possible with typical 'broad-field' irradiation methods. Using microbeams, it is possible to deliver precise doses of radiation to selected individual cells, or sub-cellular targets in vitro. This technique continues to be applied to the investigation of a number of phenomena currently of great interest to the radiobiological community. In particular, it is the study of so-called 'non-targeted' effects (where cells are seen to respond indirectly to ionizing radiation) that are benefiting most from the use of microbeam approaches. One important non-targeted effect is the 'bystander-effect' where it is observed that unirradiated cells exhibit damage in response to signals transmitted by irradiated neighbours.

We have developed a method to produce a nm sized slow highly-charged ion beam based on a self-organized charge up inside a single tapered-glass capillary. In order to investigate the characteristics of the obtained beams, the transmission of 8 keV Ar⁸⁺ beam through the capillary of 5-cm long with 800/24 μm inlet/outlet inner diameter was examined. The transmitted beam had the same size as the outlet with the beam-density enhancement of approximately 10. The initial beam was guided through a capillary tilted by as large as ±100 mrad and it still kept the incident charge. A focused ion beam of Ga⁺ was employed to manufacture the capillary outlet as small as several hundreds nm in diameter and fabricate a thin glass window at the capillary outlet for biological applications.

The acceleration of high-energy ion beams (up to several tens of MeV per nucleon) following the interaction of short (t < 1ps) and intense (Iλ²> 10¹⁸ W cm⁻² μm⁻²) laser pulses with solid targets has been one of the most important results of recent laser-plasma research. The acceleration is driven by relativistic electrons, which acquire energy directly from the laser pulse and set up extremely large (∼TV/m) space charge fields at the target interfaces. In view of a number of advantageous properties, laser-driven ion beams can be employed in a number of innovative applications in the scientific, technological and medical areas. Among these, their possible use in hadrontherapy, with potential reduction of facility costs, has been proposed recently. This paper will briefly review the current state-of-the-art in laser-driven proton/ion source development, and will discuss the progress needed in order to implement some of the above applications. Recent results relating to the optimization of beam energy, spectrum and collimation will be presented.

In this contribution, we report on photorecombination measurements of highly charged ions (HCI) that were performed using the electron cooler of the heavy-ion storage ring ESR of the Gesellschaft für Schwerionenforschung (GSI) as a target of free electrons. The experimental technique of resonance reaction spectroscopy by means of dielectronic recombination (DR) was employed in two new ways:

The determination of isotope shifts in the DR resonance spectrum of few-electron heavy ions is a novel method with unique properties for investigations at the interface between electrons and the atomic nucleus, e.g., charge radii and hyperfine effects. First results from a pilot experiment with the two isotopes A = 142 and A = 150 of Li-like neodymium ^ANd⁵⁷⁺ are discussed.

Until very recently, electron-ion collision experiments at high relative energies of more than a few keV were not accessible at the electron coolers of storage rings. Such high energies are needed to access DR processes that involve the K-shell electrons of very heavy ions. The novel approach of DR measurements with a stochastically (pre-)cooled ion beam resolves this problem. Results for the photorecombination of hydrogen-like U⁹¹⁺ in the energy range (63 keV - 74 keV) of the KLL-DR process are presented.

In this contribution, we present an experimental study carried out at GSI Darmstadt devoted to investigation of quantum electrodynamical (QED) effects for the ground states in hydrogen- and helium-like uranium. In the experiment, X-ray spectra following radiative recombination of free electrons with bare and H-like uranium ions (U⁹²⁺, U⁹¹⁺) were measured at the electron cooler of the ESR storage ring. Utilizing clean and favorable experimental conditions present at the electron cooler, we were able to obtain very accurate values for the ground-state binding energies from the observed X-ray transitions. When compared with theory, our results provide the most stringent test of bound-state QED for one- and two-electron systems in the strong-field regime.

Spectroscopic measurements on few-electron high-Z ions take guidance from isoelectronic trends of low-Z to mid-Z ions and from theory. Such wide-range extrapolations, however, are fraught with uncertainty. We discuss as examples some n = 3, Δn = 0 transitions in the EUV spectra of Na-, Mg- and Al-like ions of Au that have been observed by electron beam ion trap work and by heavy-ion accelerator based beam-foil spectroscopy. New insights are gained from notable recent progress of calculations.

We have measured and identified numerous Extreme UltraViolet (EUV) radiative line structures arising from xenon (Xe) ions in charge state q = 1 to 10 in the wavelength range 40-80 nm. To obtain reasonable intensities of different charged Xe ions, we have used a compact microwave plasma source which was designed and developed at the Lawrence Berkeley National Laboratory (LBNL). The EUV emission of the ECR plasma has been measured by a 1.5 m grazing incidence monochromator that was absolutely calibrated in the 10-80 nm wavelength range using well known and calibrated EUV light at the Advanced Light Source (ALS), LBNL. This calibration has enabled us to determine absolute intensities of previously measured EUV radiative lines in the wavelengths regions investigated for different ionization stages of Xe. In addition, emission spectra of xenon ions for corresponding measured lines have been calculated. The calculations have been carried out within the relativistic Hartree-Fock (HF) approximation. Results of calculations are found to be in good agreement with current and available experimental and theoretical data.

Relativistic multireference Møller-Plesset perturbation theory has been employed to calculate with high accuracy the energy levels and transition probabilities of Cu- to Sr-like gold ions. The many-body calculations were carried out to identify the unassigned blended lines in the 35–40 Å region of the low-energy EBIT spectrum of the gold ions [Träbert et al 2001 Can. J. Phys.79153]. Most of the prominent lines in the 35–40 Å region were identified as the emission lines in Sr-like gold.

We have undertaken a large-scale Breit-Pauli configuration interaction calculation of transitions among lower-lying levels in Mg V. We optimised orbitals to represent the main configurations (including the LS-dependency of the states under consideration) together with all the major correlation effects. All one- and two-electron replacements from a basic reference comprising the dominant configurations were allowed for in the calculation. A small selection of oscillator strengths and transition rates is presented here. We focus in this short report on transitions with the lower state dominated by the 2p⁴configuration. Our results agree closely with the calculations of Fischer but differ markedly from the recent work of Bhatia et al.

The Penning trap mass spectrometer SMILETRAP takes advantage of highly-charged ions for high-accuracy mass measurements. In this paper recent mass measurements on Li and Ca ions are presented and their impact on fundamental applications discussed, especially the need for accurate mass values of hydrogen-like and lithium-like ions in the evaluation of the electron g-factor measurements in highly-charged ions is emphasized. Such experiments aim to test bound state quantum electrodynamics. Here the ionic mass is a key ingredient, which can be the limiting factor for the final precision.

Using high-resolution x ray and extreme ultraviolet (EUV) spectrometry, the line emission of W²⁸⁺ - W⁵⁰⁺ ions was measured at the Berlin Electron Beam Ion Trap (EBIT). Our study encompasses a wide range of wavelengths (5-800 Å) and includes the observation of electric and magnetic dipole lines. The results of our measurements are compared with predicted transition wavelengths from ab initioatomic structure calculations.

Phase-integral and Newton-Raphson methods are used to calculate real turning points, energy eigenvalues and hence quantum defects (μ_n,l). Stokes and anti-Stokes lines are traced using a complex Newton-Raphson method.

BOUND-state quantum electrodynamical calculations can be tested by high precision measurements of the magnetic moment of the electron bound in hydrogen-like and lithium-like ions. Measurements of hydrogen-like carbon and oxygen achieved relative experimental uncertainties as low as 2 × 10⁻⁹. In the current experiment we plan to measure the g-factor of hydrogen-like and lithium-like calcium ions. The aim is to reach a relative uncertainty ∂g/gin the order of 10⁻⁹. Here, we will give the motivation for the experiment, present the experimental techniques and the status of the experiment.

We studied doubly excited ^1,3P^o resonant Li⁺ and B³⁺ below the n = 2 threshold by the saddle-point complex rotation method with B-spline functions. We calculated the ten lowest 1Po and ten lowest ³P^o resonant states of Li⁺and B³⁺, respectively. The doubly excited states are grouped in Rydberg series labeled by the quantum numbers K, T, A. Our results of energies and widths are in good agreement with other theoretical and experimental results.

We present a new measurement on X-ray spectroscopy of multicharged argon, chlorine and sulfur obtained with the Electron Cyclotron Resonance Ion Trap installed at the Paul Scherrer Institut (Villigen, Switzerland). For this purpose, we used a crystal spectrometer with a spherically bent crystal having an energy resolution of about 0.4 eV. High intensity Kα X-ray spectra were obtained from ions with one 1s hole ranging from almost neutral to heliumlike charge states. In particular we observed the 1s2s³S₁ → 1s²¹S₀ M1 and 1s2p³P₂ → 1s²¹S₀ M2 transitions in He-like argon, chlorine and sulfur with unprecedented statistics and resolution. The preliminary analysis presented here describes a new technique to measure precisely energy differences between transitions using a Johann-type Bragg spectrometer. A recent characterization of the spectrometer will allow for a drastic reduction of the systematic errors.

The radiative lifetime and mass isotope shift of the 1s²2s²2p²P_3/2 - ²P_1/2 M1 transition in Ar¹³⁺ ions have been determined with high accuracies using the Heidelberg electron beam ion trap. This fundamentally relativistic transition provides unique possibilities for performing precise studies of correlation and quantum electrodynamic effects in many-electron systems. The lifetime corresponding to the transition has been measured with an accuracy of the order of one per thousand. Theoretical calculations predict a lifetime that is in significant disagreement with this high-precision experimental value. Our mass shift calculations, based on a fully relativistic formulation of the nuclear recoil operator, are in excellent agreement with the experimental results and confirm the absolute necessity to include relativistic recoil corrections when evaluating mass shift contributions even in medium-Z ions.

The photorecombination spectrum of ⁴⁸Ti¹⁸⁺ was measured employing the merged electron-ion beams technique at a heavy-ion storage ring. The experimental electron-ion collision energy range 0-80 eV comprises all dielectronic recombination (DR) resonances associated with 2s → 2p (△N = 0) core excitations as well as trielectronic recombination (TR) resonances that involve 2s² → 2p² core double-excitations. At low collision energies DR resonances are observed that are associated with the excitation of metastable 2s 2p³P₀primary ions with nearly infinite lifetime for the isotope ⁴⁸Ti with zero nuclear spin. For the isotope ⁴⁷Ti with nonzero nuclear spin hyperfine quenching of these resonances occurs. The procedure for obtaining the associated time constant from a recombination measurement is outlined.

We report on an experiment aiming for a study of the radiative decay modes of the 1s(2s)2 level in Li-like uranium. The experiment was performed of initially Be-like uranium colliding with N2 molecules at an energy of 90 MeV/u. By measuring the x-ray production associated with K-shell ionization of the projectile, a high selectivity for the production of the 1s(2s)2 level is observed.

The x-ray spectra produced in collisions of 98 MeV/u Li-like uranium ions with N2 molecules have been studied. By measuring the decay photons associated with the capture process, experimental information for the formation of the excited [1s²2s2p_3/2]¹P₁ and [1s²2s2p_3/2]³P₂ states in Be-like uranium has been obtained. It was found that relative probability for production of the P-states is close to statistical population law 2J + 1.

Using the relativistic-configuration-interaction atomic structure code, RCI simulations for EUV spectra from Sn¹⁰⁺, Sn¹¹⁺ and Sn¹²⁺ ions are carried out, where it is assumed that each ion is embedded in a LTE plasma with the electron temperature of 30 eV. To make clear assignment of the measured spectra, the value of the excitation energy limit, which is introduced to limit the number of excited states in the simulation, is changed to see the excitation-energy-limit dependence of the spectral shape. The simulated spectra are obtained as a superposition of line intensities due to all possible transitions between two states whose excitation energy from the ground state is lower than the excitation energy limit assumed. The RCI simulated spectra are compared to the spectra measured with the chargeexchange- collision experiment in which a rare gas such as Xe or He as a target is bombarded by a charge-selected tin ion. Applicability of the LTE model to a decay model in the charge exchange collision experiment is also discussed.

Wavelengths and transition probabilities have been calculated for the n=4, δn=0 allowed transitions in the heavy Cu-, Zn-, Ga- and Ge-like ions with Z=70–92. Fully relativistic multiconfiguration Dirac-Fock (MCDF) computations were carried out. The present results are compared to and agree well with recent electron-beam ion-trap (EBIT) measurements in Yb, W, Os, Au, Pb, Bi, Th and U ions.

Wavelengths and intensities of extreme ultra-violet optical emissions are studied for 4d – 5p transitions of Xe¹⁰⁺ions in plasmas. The electronic states of the ions have been calculated employing a method based on the multi-con.guration Dirac-Fock approximation. Dipole transition rates have been calculated allowing the non-orthogonal orbital wavefunctions between the initial and final electronic states. Single and double electron virtual excitations have been taken into account to evaluate the electron correlations. The orbital relaxations and electron correlations have substantial effects on the formation of the transition arrays.

In this work we study the dependence of the fully differential cross sections (FDCS) for single ionization of He by 100 MeV/amu C⁶⁺ on the momentum transferred by the projectile to the target. Three dimensional plots of the FDCS are used to illustrate how the different configurations contribute when the theoretical results are convoluted over the experimental uncertainties. This convolution is shown to be essential in order to properly reproduce the measured data.

The CTMC method is used to calculate emission cross sections following charge exchange processes involving highly charged ions of astrophysical interest and typical cometary targets. Comparison is made to experimental data obtained on the EBIT-I machine at Lawrence Livermore National Laboratory (LLNL) for O8+ projectiles impinging on different targets at a collision energy of 10 eV/amu. The theoretical cross sections are used together with ion abundances measured by the Advanced Composition Explorer to reproduce cometary spectra. Discrepancies due to different estimated delays of solar wind events between the comet and the Earth-orbiting satellite are discussed.

In this paper we report atomic data, namely energy levels, radiative rates, lifetimes, collision strengths, and excitation rate coefficients, for transitions among 89 levels of the (1s²) 2s² 2p⁶, 2s² 2p⁵3l, 2s2p⁶ 3l, 2s² 2p⁵4l, and 2s²p⁶4l configurations of Ni XIX. For the calculations of energy levels and radiative rates the grasp code has been adopted, whereas for the calculations of collision strengths darc is employed.

Ionization and fragmentation of CO molecules have been investigated in chargechanging collisions of 6 MeV O⁴⁺ ions. Fragment ions from CO were measured in coincidence with outgoing projectile charge states by means of a momentum 3D imaging technique. Cross sections for the production of fragment ions in electron loss and capture collisions were obtained as a function of the angle between the molecular axis and the beam direction. It was found that double ionization (CO)²⁺ induces rather isotropic molecular fragmentation for both electron capture and loss collisions. On the other hand, triple ionization (CO)³⁺ was found to induce highly anisotropic fragmentation during electron loss collisions.

We have performed a 14-state R-matrix calculation to determine effective collision strengths for fine structure transitions in S v ion. The target states were taken to be the 14 lowest LS states, which involve configurations of the form - (2p⁶)3s², 3s3p, 3p², 3s3d, 3s4s, 3p3d. These target states give rise to 26 fine structure levels and 325 possible transitions. The fine structure collision strengths were obtained by transforming to a jj-coupling scheme using the JAJOM program of Saraph and using a sufficiently fine energy mesh so that the resonance structure can be be properly delineated. Effective collision strengths were calculated by averaging the electron collision strengths over a Maxwellian distribution of velocities. Comparisons are made with an earlier R-matrix calculation and with a distorted-wave approximation.

Impact of slow alpha particles (He²⁺) on H₂ and O₂ is relevant for radiation cooling in future magnetically confined burning fusion plasmas. A new compact experimental setup has been utilized for measuring absolute cross sections for single (SEC) and double electron capture (DEC), and transfer ionization (TI) in collisions of slow (impact energy typically 0.1–1 keV times ion charge) singly and multiply charged ions with atoms and molecules. Our method combines collection of slow product ions and electrons with primary ion beam attenuation and stopping in a differentially pumped target gas chamber. Reliability of the new setup has been checked by measuring well established SEC and DEC cross sections for impact of slow singly and doubly charged noble gas ions on their atoms (He, Ne, Ar). We have then measured absolute cross sections for SEC by both ³He²⁺ and ⁴He²⁺ from Ne, and in further consequence will study fusion relevant SEC and DEC by He²⁺ from H₂ and O₂.

The emission of electrons from autoionizing He^** outgoing projectiles formed in a double capture 30 keV He²⁺ +H₂ collision has been analysed at detection angles ranging from 90° up to 162°. The autoionization cross section differential in the angle is found to oscillate. This result is attributed to a Young interference mechanism produced by the postcollisional interaction of the emitted electron with the two-centre exploding H⁺ + H⁺ residual target.

X-ray emission of highly charged argon ions following charge exchange collisions with argon atoms has been measured as a function of projectile energy. The ions are extracted from the Electron Beam Ion Trap (EBIT) in Berlin and selected according to their massto-charge ratios. Experiments focussed on hydrogen-like and bare argon ions which were decelerated from 125q eV/amu to below 0.25q eV/amu prior to interaction with an argon gas target. The x-ray spectra recorded probe the cascading transitions resulting from electron capture into Rydberg states and are found to vary significantly with collision velocity. This indicates a shift in the orbital angular momentum of the capture state. Hardness ratios are observed to increase with decreasing projectile energy though at a rate which differs from the results of simulations. For comparison, measurements of the x-ray emission following charge exchange within the trap were carried out and are in agreement with the findings of the EBIT group at LLNL. Both of these in situ measurements, however, are in discrepancy with the results of the experiments using extracted ions.

We calculate the stopping powers of H₂ for the Li projectiles by using rate equation and Monte Carlo methods. We treat the change in the charge number of the projectiles by using some atomic and molecular processes. The stopping powers by solving the rate equations agree well with those averaged by 100 trials by the use of the Monte Carlo method.

Using the translational energy-gain spectroscopy technique, we have measured the energy-gain spectra and absolute total cross sections for single-electron capture in collisions of O³⁺ ions with He, H₂O and CO₂ at impact energies between 0.3 and 1.2 keV and scattering angles between 0° and 6°. At the lowest collision energy, 300 eV, the energy-gain spectrum for O³⁺ - He collisions indicates that single-electron capture into the 2s2p³³P state of the product O²⁺ is the dominant reaction channel observed with smaller contributions from capture into the 2s2p³¹D, ³S and ¹P states. For O³⁺ - H₂O collisions, the dominant peak correlates with capture into the 2p3p state of O²⁺, with a significant contribution involving capture into the 2p3s state. In O³⁺ - CO₂ collisions, the dominant reaction channel is due to capture into the 2p3s state of O²⁺, with contributions from capture into the 2p3p state. The measured cross sections are compared with the available measurements and theoretical results based on the multi-channel Landau-Zener (MCLZ) model.

Single-electron capture in collisions of highly charged ions Xe¹⁸⁺ and Xe²⁴⁺ with Na atoms is investigated by measuring the momenta of the Na recoil ions. The Q-value spectrum in Xe¹⁸⁺ + Na collisions shows capture into lower n states compared with Classical over-barrier model (CBM) calculations. Partial cross sections for capture into n = 13...20 for Xe¹⁸⁺and n = 19... 24 for Xe²⁴⁺, extracted from Q-value spectra, show no obvious dependence in the energy range available for our experiment (0.5-4.5 keV/amu).

We present total cross sections for electron capture and ionization in collisions of B⁵⁺ and Ne¹⁰⁺with H(2s), calculated using two methods: the semiclassical close-coupling molecular formalism and the eikonal-CTMC method. We have evaluated partial cross sections for capture into excited n-levels, required in plasma diagnostics.

Recent experimental data for fully differential cross sections (FDCS) have been compared to various continuum-distorted-wave eikonal-initial-state (CDW-EIS) models without much success, despite good agreement with double-differential cross sections. We present theoretical results from a four-body problem for FDCS of 3.6 MeV/u Au^Z+_P + He collisions, Z_P = 24, 53, with ejected electron energy of 4 eV. Theoretical results for the inclusion and omission of the internuclear potential are given. Results are an improvement on current CDWEIS calculations for these collisions, especially in the Au²⁴⁺case.

The radiative electron capture into (initially) lithium-like ions is studied within the framework of the density matrix approach. Special attention is paid to the magnetic sublevel population of the residual ionic states which is described by a set of alignment parameters. Detailed calculations of these parameters have been performed for the capture into the 1s² 2s 3d_3/2J_f = 2 level of high-Z ions along the beryllium isoelectronic sequence. We devote special attention to the modifications in the many-electron case as opposed to singleelectron systems. The electron correlation leads to an enhancement of the alignment, which becomes more pronounced as the nuclear charge decreases and the electron-electron interaction gains in strength as compared to the electron-nucleus interaction.

Electron interferences associated with coherent two-centre emission in 1-5 MeV H⁺ + N₂ collisions are investigated. Spectra were measured for ejected electrons with energies from 5-410 eV and observation angles in the range 30° to 150°. Experimental molecular N₂cross sections were normalized to theoretical atomic N cross sections, revealing oscillatory structures that do not change significantly with observation angle or collision velocity. It is suggested that the oscillations are due to previously observed secondary interferences arising from intramolecular scattering following ejection of a K-shell electron.

The Classical-trajectory Monte-Carlo (CTMC) model provides an excellent description of the electron capture to the continuum (ECC) cusp in atomic ionization collisions whenever the electron-projectile interaction is of a Coulomb or even of a dipolar type. However, in this communication we show that this description fails for the case of a polarizability potential, such as in the one produced by a neutral He (2¹S) outgoing projectile. Actually the CTMC calculation predicts an ECC peak that is much broader and smaller than for a Coulomb interaction, a result that differs from experimental data and quantum-mechanical calculations.

Recent spectroscopic models of active galactic nuclei have indicated that the recommended electron-ion recombination rate coeficients for iron ions with partially filled Mshells are incorrect in the temperature range where these ions form in photoionized plasmas. We have investigated this experimentally for Fe⁷⁺ forming Fe⁶⁺, Fe⁸⁺ forming Fe⁷⁺, and Fe¹³⁺ forming Fe¹²⁺. The recombination rate coeficient was measured employing the electron-ion merged beams method at the Heidelberg heavy-ion storage-ring TSR. The measured energy range encompassed at least all dielectronic recombination (DR) resonances associated with core excitations within the M-shell of the parent ions. Already in our first measurement, that is for Fe¹³⁺, we find unusually strong DR resonances at low electron-ion collision energies leading to low temperature plasma DR rate coeficients orders of magnitude larger than the recommended rate coeficient.

We have calculated charge transfer total cross sections in ion-H(1s) collisions at very low energies (E < 1 eV). These cross sections show a Langevin-type behaviour, although the corresponding transition probabilities are smaller than one, as obtained in the Landau-Zener model. The cross sections exhibit numerous spikes which are related to the existence of resonant states in the adiabatic potential of the quasi-molecule formed during the collision.

Extreme ultra-violet emission spectra of multiply charged Xe and Sn ions are measured following the electron capture in collisions with He. After the assumption of singleelectron capture, we have found that the wide range of charge states, Sn¹⁰⁺ to Sn¹⁴⁺ for tin ions, and Xe¹¹⁺ to Xe¹⁷⁺for xenon ions, have the prominent emissions at 13.5 and 11.0 nm, respectively. These emissions are attributed to the 4d-4f unresolved transition arrays in comparison with the results of theoretical calculations by using the HULLAC code.

Extreme ultra-violet (EUV) spectra of multiply charged tin ions were measured in the wavelength range of 5-38 nm following the electron capture into excited states of slow Sn^q+(q = 6-15) ions passing through He gas target. The charge-state dependence of 4d-nl (nl = 4f, 5p and 5f) transitions was obtained with assumption of the single-electron capture. Identi.cation of the transitions has been carried out by comparison with the results of the theoretical calculation.

Interference between radiative and dielectronic recombination in electron and highly charged Bi ion collisions has been studied by observing emitted x-rays with the Tokyo electron beam ion trap. The so-called Fano line shapes were fitted to the KLL DR resonant profiles observed as the enhancement of the x-ray counts. The shape parameters q have been determined similarly to the previous experiments for highly charged U [D A Knapp et al 1995 Phys. Rev. Lett.74 54] and Hg ions [A J Gonzalez Martinez et al 2005 Phys. Rev. Lett.94 20320]. The present results were compared to the previous results.

Radiative processes occurring in collision of decelerated bare uranium ions and molecular hydrogen are studied at the heavy-ion storage ring ESR. The combination of the deceleration technique and the narrow Compton profile of molecular hydrogen allowed us to resolve a multitude of REC transitions into the bound states of the projectile and to resolve unambiguously the tip region of primary bremsstahlung. For this purpose, a supersonic molecular hydrogen jet-target, precooled with liquid nitrogen and optimized for long-term stability, was applied.

The three-center Coulombic over-the-barrier model is developed for the Coulomb explosion of a homonuclear diatomic molecule in collisions with a slow (∼ 10 eV/amu) highly charged ion. A conventional two-step picture of multiple electron transfer followed by Coulomb explosion is far from appropriate because the molecule BC sets out to dissociate before the ion A approaches the closest distance. We treat the formation of a quasimolecule ABC and its decay into the three moving atomic ions, where two possible processes are considered for population in an atomic site B as ABC → BC → B and ABC → AB → B. It is shown that the contribution from the second process is crucial in a slow collision. Charge-asymmetric fragmentation between sites B and C observed in a triple-coincidence measurement is suggested to re.ect the bond elongation during a collision. Collisions of Kr⁸⁺ +N₂are analyzed.

The process of electron recombination is investigated considering the possible resonant channel of nuclear excitation by electron capture (NEEC), in which a continuum electron is captured into a bound state of an ion with the simultaneous excitation of the nucleus. Transition rates and total cross sections for NEEC followed by the radiative decay of the nucleus are presented for various heavy-ion collision systems. The role played by radiative recombination (RR) in the NEEC recombination mechanism is investigated and theoretical estimates of the magnitude of the interference between the two processes are presented. We discuss the experimental possibility of discerning NEEC from the RR background, studying the angular distribution of the radiation emitted in the two processes.

The post-collisional interactions in ion-atom ionization collisions are studied around the electron capture to the continuum (ECC) process. For this purpose, a suitable double differential cross section is introduced, involving the longitudinal recoil-ion momentum and the projectile transverse momentum transfer. Using the fact that the ECC process is closely related to the threshold in the longitudinal momentum distribution, we study this distribution as a function of the projectile scattering angle. Using the CDW-EIS approximation we theoretically find a focusing (defocusing) effect as we get closer to the distribution threshold for proton (antiproton) impact on He atoms.

We present CDW-EIS theoretical calculations for the projectile deflection in single ionization of Helium by heavy-ion impact as a function of ionized electron energies. These calculations account for the projectile-residual target ion interaction through a first order static potential and a second order polarization potential. The results are compared with recent experimental data by impact of 3.6 MeV/amu Au53+. A good agreement is found.

Detailed multicon.guration Dirac-Fock calculations with the inclusion of the transverse (Breit) interaction and QED corrections have been carried out on zirconium to elucidate the structure of various M-, N-shell satellite and L-shell hypersatellite L_α1,2 (L₃M_4,5) and L_β1(L₂M₄) lines in its X-ray spectra. For each type of lines two theoretical spectra have been synthesized: one being a sum of the Lorentzian natural line shapes and the other one being a convolution of the sum of the Lorentzian natural line shapes with the Gaussian instrumental response. The results are very helpful in reliable interpretation of various high-resolution L-X-ray spectra of zirconium target bombarded by different light and heavy projectiles.

Recent activities at the Tokyo electron beam ion trap related to observations of resonant processes in the collisions of electrons with open-shell highly charged ions are reported. Extracted ion observations and high resolution x-ray spectroscopic observations have been applied to resolve the contribution from different charge states. In particular, dielectronic recombination (DR) of a H-like ion have been observed by high resolution x-ray spectroscopy for the first time. The DR satellite spectra obtained in the present experiment are compared with theoretical spectra.

In the present work we calculate multiple ionization cross sections, as a function of the orientation of the molecular axis with respect to the ion beam, for impact of highly charged ions on N₂ and O₂molecules. We use different approaches to obtain the single ionization probabilities that are necessary to compute these quantities into the Independent Electron Model. The in.uence of the molecular orientation on differential cross sections is analized. An adequate description of existing data is obtained.

We have measured energy gain spectra for single-electron capture collisions of Helike C, N and O ions with H₂ at 50 eV/u. Energy gain spectra were examined with energy gain functions calculated from a classical over barrier model, and we obtained fairly good agreement between experimental and calculated results. We find that single electron capture occurs predominantly for C⁴⁺ and O⁶⁺ ions, while for N⁵⁺ ions double electron capture followed by transfer ionization is the dominant process in the formation of N³⁺ions.

Single electron capture cross sections have been measured for collisions between O⁷⁺ and He at energies from 1 eV/q to 1keV/q. Experimental cross sections are compared with those for H-like ions of C⁵⁺ and N⁶⁺ impacts. Cross sections for C⁵⁺ and O⁷⁺ are found to depend only weakly on the collision energy, while those for N⁶⁺vary rather strongly. By using a velocity-dependent classical over barrier model, the energy dependency is accounted for qualitatively.

We report in this paper the computation of accurate total collision strengths and effective collision strengths for electron-impact excitation of FeII, using the parallel R-matrix program PRMAT. Target states corresponding to the 3d⁶4s, 3d⁷, 3d⁶4p and 3d⁵4s4s basis configurations were included in the calculations giving rise to a 113 LS state 354 coupled channel problem. Following a detailed systematic study of correlation effects in both the target state and collision wavefunctions, it was found that an additional 21 configuration functions needed to be included in the Configuration Interaction expansion to obtain significantly more accurate target states and collision wavefunctions. This much improved 26-configuration model has been used to calculate converged total effective collision strengths for all sextet to quartet transitions among these levels with total spin S = 2, giving a total of 1785 lines. These calculations have laid the foundation for an approach which may be adopted in the study of electron collisions with the low ionization stages of other iron peak elements. The work has been further extended with the commencement of a Breit-Pauli relativistic calculation for one of the smaller models and includes 262 fine-structure levels and over 1800 coupled channels. At the same time the PRMAT parallel R-matrix package is being extended to include relativistic effects which will allow us to attempt the more sophisticated 26-configuration model and produce for the first time the amount and quality of atomic data required to perform a meaningful synthesis of the Fe II spectrum.

For initially bare and hydrogen-like uranium ions (U⁹²⁺ and U⁹¹⁺, respectively) a drastic difference in the emission characteristics is observed for the corresponding Ly-α₁ and K-α₁ cascade photons after radiative electron capture (REC) into the L shell of the projectile. Whereas the Ly-α₁ x-rays are emitted preferentially perpendicular to the ion flight direction, the K-α₁ photons show practically an isotropic emission pattern in the ion frame. Both, Ly-α₂ and K-α₂radiation are emitted isotropically with respect to the ion. Analytical calculations in lowest order for the L-REC—K-x-ray cascade process concur nicely with the experimental findings for the energy region investigated (70 - 300 MeV/u).

We have investigated the effect of Young type interference on the forward backward angular asymmetry in electron emission from molecular hydrogen in collisions with fast bare carbon ions. The asymmetry parameter shows an oscillatory behaviour as a function of electron velocity which is absent in atomic target such as He. It is shown that the asymmetry parameter which is based on DDCS from H₂only can be a tool to investigate the Young type interference. The measured energy and angular distributions as well as the asymmetry parameter are compared with a molecular CDW-EIS (continuum distorted wave-eikonal initial state) model.

We demonstrate that in order to interpret the x-ray satellite structure of Pd Lα_1,2(L₃M_4,5) transitions excited by fast O ions, which was measured using a high-resolution von Hamos crystal spectrometer, the vacancy rearrangement processes, taking place prior to the x-ray emission, have to be taken into account. The measured spectra were compared with the predictions of the multi-con.guration Dirac-Fock (MCDF) calculations using the fluorescence and Coster-Kronig yields which were modiffed due to a reduced number of electrons available for relaxation processes and the effect of closing the Coster-Kronig transitions. We demonstrate that the vacancy rearrangement processes can be described in terms of the rearrangement factor, which can be calculated by solving the system of rate equations modelling the flow of vacancies in the multiply ionized atom. By using this factor, the ionization probability at the moment of collision can be extracted from the measured intensity distribution of x-ray satellites. The present results support the independent electron picture of multiple ionization and indicate the importance of use of Dirac-Hartree-Fock wave functions to calculate the ionization probabilities.

A position sensitive detector for measuring field ionized electrons in the fringe field of a dipole magnet is presented. The detector provides a means to study, in a state selective fashion, recombination into high Rydberg states and offers a new method to investigate recombination enhancement effects. Several experimental considerations and possibilities are discussed in the text.

A new laboratory for highly charged ions is being built up at Stockholm university. An electron beam ion trap (EBIT) (3T magnet,⩽30 keV electron beam) was installed. It is used for spectroscopic studies, precision mass measurements, electron ion collisions, and highlycharged ion surface studies. Here we report about a fast ion-extraction scheme from ebit and first results using a time-of-flight detection as well as a labview based operational system of ebit.

We have investigated the relation of forward emission cusp electron spectra and bremsstrahlung for 90AMeV U⁸⁸⁺ + N₂at the internal supersonic gas jet target of the ESR storage ring of GSI. We find that x ray photons measured in coincidence with cusp electrons originate from the short wavelength limit of the electron nucleus bremsstrahlung.

Electron capture processes between low energy multi-charged ions and atoms are studied by an energy loss spectroscopy technique. Energy-loss spectra of charge-state-changed projectile ions scattered in the forward direction in collisions of Xe^q+(up to q = 11) ions with He and Ar atoms have been measured at a collisional energy of 9 keV. The results are discussed using the classical over-barrier model.

We have developed a relativistic version of the distorted-wave theory (RCDWEIS)to simulate the process of electron capture via pair production. Results are compared with experimental cross section data for La⁵⁷⁺ impact on Gold, Silver and Copper targets. An observed enhancement with increasing Z_T is evident, with the results found to be in better agreement with experiment than previous similar simulations. The theory is extended to give total cross sections for the interaction of U²⁸⁺and a bare Argon ion.

Slow multiply charged ions are efficiently guided through nano-capillaries with large aspect ratio in polyethylene terephthalate (PET), due to self-organized charging of the inner capillary walls which prevents close collisions with the surface. In order to gain more insight into this interesting phenomenon we have measured the 2-D scattering distribution of transmitted ions during the charge-up process.

The transmission of highly collimated multicharged ions through alumina nanocapillary arrays was studied using 200 MeV and 10- to 20-keV/q ion beams. The aligned nanopores each have a diameter and length of 100 nm and 60 μ, respectively. Emergent charge-state-selected angular distributions were measured at low energy. The distributions consist of sharp two-dimensional peaks that sit on a continuum distribution. Analysis of the results from target tilting experiments indicate that the observed structure can be explained simply by multiple collisions of the projectile with nanopore walls. We discuss these results and other effects produced by applying a fine wire mesh and Au thin films to the nanocapillary array.

Stark mixing of intermediate excited ionic states due to combined action of crystal lattice, polarization wake potential and collisions with electrons is considered theoretically. Calculations for radiative recombination of well-channeled Ar and Kr ions under planar channeling in Si crystal show significant influence of the mixing of [n = 2] states on formation of the X-ray spectra and angular correlation between L-REC and K_α1 photons.

We present scanning tunneling microscope (STM) images, atomically resolved, of the nanostructures on various kinds of surfaces bombarded with highly charged ions (HCIs). In the STM image of a highly oriented pyrolytic graphite surface (Xe²⁹⁺-impact), a protrusion structure was observed with √3 × √3 R30° surface reconstruction around the impact site. A crater-like structure was formed on a Si(111)-(7×7) surface by an I⁵⁰⁺-HCI impact. An atomic image of ∼0.1 nm in height was also observed around the missing topmost layers of the crater. In the case of a TiO₂(110) surface, a typical nanostructure induced by a single I⁵¹⁺-HCI impact, relatively larger crater structure than that on the Si surface was observed; the height (∼1 nm) was higher than the atomic step of the TiO₂(110)-(1×1) surface (∼0.3 nm) and the depth reached at least 1.5 nm. This implies that the degree of the HCI-radiation effect on the TiO₂ surface is higher than that of the Si(111) case.

K Auger electrons emitted from excited N ions produced by multi electron transfer from the inner surface of a metallic microcapillary were observed in the energy region of 310-400 eV, for 60keV N⁶⁺incident ions. The lower energy part (310-340eV) can be attributed to Auger electrons from Li- and Be-like excited states in vacuum, which may have information about decay processes of the hollow atoms (ions), which has not been observed by previous ion-surface collision experiments. The higher energy part (340-400eV) of the spectrum may be attributed to Auger electrons from hollow atoms (ions) and from Li-like K-LM Auger electrons.

X-rays emitted in the collisions of highly charged ions with a surface have been measured to investigate dissipation schemes of their potential energies. While 8.1% of the potential energy was dissipated in the collisions of He-like I ions with a W surface, 29.1% has been dissipated in the case of He-like Bi ions. The x-ray emissions play significant roles in the dissipation of the potential energies in the interaction of highly charged heavy ions with the surface.

We present results of a numerical computer simulation based on the extended dynamical classical over the barrier model (EDCOM). To get an energy balance for the transferred potential energy of the highly charged ions (HCIs) to the solid surface, we apply an additional extension of the model evaluating the energy loss of Auger electrons which are generated during the relaxation of the HCI. From the results of the simulation we can distinguish between the potential energy deposited in the nuclear system due to image charge acceleration of the incoming HCI and the potential energy which is released over Auger processes. Further, we break down this energy into that which is deposited in the solid and that which is re-emitted due to escaping secondary electrons.

We have measured the rate of negative ion formation in F⁺-C₆₀ collisions at different projectile velocities (v • 0.1 a.u to 0.4 a.u.). The measured rate has been found to decrease from 9.6% to 7.1% for projectile energy increasing from 7.3 keV to 18.3 keV. The fragmentation patterns of C₆₀^r+multicharged ions charged r+ formed in the collisions have been analyzed.

We have observed nanodots on a highly orientated pyrolytic graphite (HOPG) surface produced by highly charged ion impacts using a scanning tunneling microscope. Previous measurements have con.rmed the dominant role of the potential energy or the incident ion charge state on the size and height of the observed nanodots. The present results extend these previous measurements to much lower kinetic energy. It appears that there is no observable influence on the lateral size of the nanodots due to the incident ion kinetic energy down to approximately 200 eV. In contrast some slight reduction in the nanodot height was observed as the kinetic energy was reduced.

The damage induced in supercoiled plasmid DNA molecules by low energy (<500 eVu⁻¹) carbon ions has been investigated as a function of ion dose. The production of short linear fragments through multiple double strand breakage is suggested and exponential dose responses for each of the topoisomers are presented.

We investigated resonant coherent excitation of H-like Ar¹⁷⁺ and He-like Ar¹⁶⁺ ions planar channeled in a Si crystal under the V-type and ladder-type double resonance conditions. In both cases, we observed distinct enhancement in the ionized fraction of the transmitted ions when the double resonance conditions were satis.ed. In the ladder-type configuration, the enhancement indicates that the doubly-excited 2p² state of He-like Ar¹⁶⁺was produced through doubly-resonant coherent excitation.

Doubly-excited 2s⁻¹2p⁻¹3pnp autoionizing resonance series of Ne atom as well as autoionizing resonances in the 2s region of Na and Mg atoms have been studied with monochromatized synchrotron radiation. Use of charge-separated photoion-yield method allowed us to detect these weak resonances in a clarified way in the yield curves of doubly-charged ions. The observed resonance states have been interpreted with the help of MCDF calculations, and the decay processes of these resonance states are discussed briefly.

The ionization energies and the corresponding photoionization cross sections from the 1s, 2s, 2p and 3s subshells of Fe¹⁵⁺ are calculated systematically using a newly developed program RERR06 for the first time, which is based on the widely used GRASP92 and RATIP packages. In the calculation, the effects of configuration interaction and orbital relaxation have been considered. As a result, the shake-up processes accompanied by the main photoionization processes have been treated as uni.ed. It is found that the present calculations for ionization energies are in good agreement with existing data and the photoionization (PI) cross sections for the 2pelectron are also in good accordance with recent computations. The contribution from the shake-up processes are found to be not important for the photoionization of Fe¹⁵⁺, but an enhancement feature is noticed for the 2p to 3p shake-up process accompanied by the PI of the 3s electron.

Ultrashort (< 15 fs) high intensity (10¹⁴-10¹⁶ W cm⁻²) laser pulses have provided novel methods for investigation of the dynamics of simple molecular ions such as H⁺₂ and D⁺₂. In this paper we report on simulations carried out for the D⁺₂ molecular ion, within the Born- Oppenheimer and two-state approximations. These simulations allow one to investigate the dissociation dynamics of the D⁺₂ molecular ion when subjected to such ultrashort, intense laser pulses. In particular, these simulations are compared to the results from recent pump-probe experiments, in which, the nuclear vibrational motion of D⁺₂has been imaged. Simulations suggest that the nature of the dissociation process, be it 1- or 2-photon, may be influenced by the tuning of the pump-probe delay time.

The vibrational wavepacket revival of a basic quantum system is demonstrated experimentally. Using few-cycle laser pulse technology, pump and probe imaging of the vibrational motion of D⁺₂ molecules is conducted, and together with a quantum-mechanical simulation of the excited wavepacket motion, the vibrational revival phenomenon has been characterised. The simulation shows good correlation with the temporal motion and structural features obtained from the data, relaying fundamental information on this diatomic system.

Ultrashort intense laser pulses have been used to initiate and image a dissociating D⁺₂nuclear wavepacket. Using a pump probe technique, the temporal evolution of the dissociation process has been observed as well as interferometric effects and signatures of bound wavepacket motion.

High-resolution photoionization experiments were carried out with beams of C III, N IV, and O V containing roughly equal amounts of ground-state and metastable ions. The energy scales of the experiments are calibrated with uncertainties of 1 to 10 meV depending on photon energy. These data favorably compare with state-of-the-art R-matrix calculations carried out on an energy grid with a spacing of 13.6 μeV.

Absolute cross-section measurements for resonant double photoexcitation of Li⁺ions followed by autoionization have been performed at high resolution in the photon energy range from 148 eV, just below the (2s2p, ₂(0,1)⁺₂) resonance to 198 eV (the region of the double ionization threshold). The measurements have been made using the photon-ion merged-beam endstation at the Advanced Light Source, Lawrence Berkeley National Laboratory, USA. The absolute cross-section measurements show excellent agreement with theoretical results from the R-matrix plus pseudo-state (RMPS) method.

We have performed time of flight (TOF) analysis to determine the intensity of ion distribution from tin based plasma for a range of charged tin ions (Sn¹⁺-Sn¹⁰⁺). A Nd:YAG laser operating at 1064 nm with a full width at half maximum pulse duration of 5.2 ns was used to create the plasma under vacuum with a base pressure of 10⁻⁶ Torr. The plasma formation occurred on a custom made optical system, which could be rotated with respect to the detector so TOF analysis could be preformed at various angles of emission, while maintaining a normal angle of incidence for the laser pulse with respect to the target. The detector used was an energy sector analyser (ESA), which is a well-characterised diagnostic capable of measuring ion energy and discriminating by charge state. Analysis was performed on ions of various charge states, with energy/charge state ratios ranging from 3 keV to 50 eV, for angles of emission from the plasma ranging from 90 to 15 degrees.

A compact 14.5 GHz electron cyclotron resonance ion source (ECRIS) for production of multiply charged ions (MCI) with a plasma-confining magnetic field generated by permanent magnets has been constructed. Microwave power with frequency between 12.75 and 14.5 GHz is transmitted from ground potential via an insulating window into the watercooled plasma chamber fitted with an aluminium liner. The HF coupling system serves as biased electrode. Operation in the gas-mixing mode is achieved with two remotely controlled gas inlet valves. The triode ion extraction system has been optimized for low acceleration voltages between 1 and 10 kV. The ECRIS is fully computer-controlled and can be remotely operated via Ethernet. Finally, we refer to recent experimental work on collisions of slow MCI generated by the new ECRIS with neutral gas particles and surfaces.

We present first experimental investigations on the Dresden EBIS-A, an advanced design of the Dresden EBIT. The Dresden EBIS-A, an EBIT machine working at roomtemperature is equipped with a NdFeB ring magnet system producing a magnetic field on axis of about 620 mT. The measurement of integral ion pulses from the ion source yield a number of extracted elementary charges in the order of 109 per ion pulse. It is shown that the width of the ion pulse can be changed from microseconds up to several tens of microseconds varying the potential of the third drift tube section. The measurement of separated charge states provides an indication of an increased ion output compared to that of the Dresden EBIT. X-ray spectra account for the production of ions such as Ar¹⁷⁺, Xe⁴⁴⁺ and Ce⁴⁹⁺in the electron beam of the ion source.

A new method for injection of metallic elements into an electron-beam ion trap (EBIT) is described. Injection of metallic elements into an EBIT has so far been mainly achieved by MEVVA (metal vapor vacuum arc) ion sources. However, continuous injection, as is the case of rare gases, is sometimes desirable, especially for stable extraction of highly charged ions. In the course of DR (dielectronic recombination) study, we have developed a method of such a stable injection of metallic elements. This method is applicable to any metallic elements or metallic compounds that have vapor pressures of ∼0.1 Pa at a temperature lower than 1900°C. We have employed this method for the extraction of highly charged ions of Bi, Er, Fe, Ho and W.

The latest commissioning experiment of a two arm transmission crystal x-ray spectrometer along with high-performance position-sensitive microstrip germanium detectors is presented. The goal of the experiment was to observe with high resolution the Ly-α-transitions of H-like Pb⁸¹⁺produced in collisions with Kr atoms. Due to a photon e.ciency of only 10⁻⁸ the position sensitivity as well as the energy and time resolution of segmented solid state Germanium detectors are absolutely essential for experiments using crystal x-ray spectrometers dealing with beams of heavy ions. A detector system with the desired properties has become available through a collaboration with the Forschungszentrum Jülich.

We report on a first prototype 2D μ-strip germanium detector, developed at IKP-Jülich, and its performance test at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Beside an accurate determination of the detector response function, the polarization sensitivity has been addressed in this study. For this purpose photon beams at energies of 60 keV and 210 keV have been used.

The construction and results of the Monte-Carlo ray-tracing simulations for a low energy x-ray crystal spectrometer designed for future experiments at the ESR storage ring with fast highly charged ions are presented. The spectrometer has a radius of the Rowland circle R = 0.5 m and operates in the Johann geometry. The x-rays emitted from a source are diffracted by spherically bent silicon Si(111) crystal and registered by two-dimensional deep depleted back-illuminated CCD camera. The estimated spectrometer efficiency, calculated according to a dynamical theory of x-ray diffraction is about 10⁻⁶. The energy resolution of the spectrometer obtained from the simulations is about 0.5 eV. Influence of the source size and Doppler broadening on the spectrometer resolution is discussed.

In this report, a brief description of the progress of the Shanghai EBIT project is presented. This is followed by short discussions on the X ray spectra at several electron beam energies and the ion densities in the EBIT at a specific running condition.

In order to determine position, dimensions and intensities of multiply charged ion beams at the mVINIS Ion Source, a novel method was developed based on a fluorescent screen and a commercial digital TV camera. The spatial characteristics of multiply charged ion beams (for example the ionization states of Ar²⁺ to Ar¹⁰⁺) have been precisely measured and analyzed at the TESLA Accelerator Installation for the first time. In this work, we discuss in details the characteristics of Ar⁸⁺ion beams. The obtained ion beam characteristics were compared with the results of previously applied conventional methods of ion beam diagnostics.

We have used the well known metal-ions-from-volatile-compounds (MIVOC) method at the mVINIS Ion Source to produce the multiply charged ion beams form solid substances. Based on this method the very intense and stable multiply charged ion beams of several solid substances having the high melting points were extracted. The ion yields and the spectra of multiply charged ion beams obtained from solid materials like Fe and Hf will be presented. We have utilized the multiply charged ion beams from solid substances to irradiate the polymers, fullerenes and glassy carbon at the low energy channel for modification of materials.

The LPCTrap facility, coupled to the low-energy beam line LIRAT of the SPIRAL source at GANIL (France), has been designed to perform in-trap decay experiments. In this contribution, we describe the experimental setup devoted to the measurement of the β-v angular correlation coefficient a_GT in the pure Gamow-Teller β decay of 6He⁺. This coefficient constitutes a sensitive observable to search for exotic couplings in the weak interaction. We present the first β-recoil spectra obtained using this technique that will provide a new precision measurement of a_GT.

The recently developed SECRAL (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou) ion source is a high-performance nextgeneration ECR ion source. It is designed to produce high current, high charge state heavy ion beams for HIRFL (Heavy Ion Research Facility in Lanzhou) cyclotrons. In August 2005, the first plasma was obtained at 18 GHz. Preliminary performances of SECRAL on gaseous elements such as oxygen, argon and xenon are quite promising, with many world record ion beams being delivered such as 2.3 emA O⁶⁺, 0.81 emA O⁷⁺, 0.81 emA Ar¹¹⁺, 0.5 emA Xe²⁰⁺, 306 eμA Xe²⁷⁺and 9 eμA Xe³⁶⁺. In April 2006, metallic ion beam production was tested on SECRAL. Very preliminary but promising results were obtained. This paper briefly describes the design of the SECRAL ion source, the ion beam analyzing system and also the ion beam detection system. Typical gaseous and metallic performances of SECRAL at 18GHz are presented.

The possibility of using x-radiation from bare and hydrogen-like highly charged ions as a driver for a proposed form of cancer therapy is discussed. This proposed form of therapy, called resonant combination therapy, benefits from a very high contrast ratio between dose to the tumour and dose to the surrounding healthy tissue as is illustrated by some simple model calculations of isodose/ion distributions. The need for further radiobiological measurements and ion source developments in order to make this form of therapy feasible are highlighted.

The well established program SUK (Sukzessive Ionisierung) for the evaluation and graphical presentation of charge state evolution has been improved by including RR (radiative recombination) and CX (charge exchange). It has options for continuous or pulsed feed of single charged ions, ion heating by Coulomb collisions of electrons limited by loss, residual gas pressure and plotting controls. SUK recently has been renamed to CBSIM (charge breeding simulation) and is run from a GUI (graphical user interface). Future developments are intended to make the program universal for any charge breeding simulation, including ECRs.

We describe how short-pulse high-intensity lasers and laser generated ion-, electronand table-top XFEL-beams may contribute in the future to SPARC or the FAIR project at GSI.

This paper mirrors and provides references to an invited review talk delivered by the first author at the 13th International Conference on the Physics of Highly Charged Ions. It briefly updates and extends an earlier review (J. D. Gillaspy, 2001 J. Phys. B: At. Mol. Opt. Phys. 34, R93-R130).