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APPA at FAIR: From fundamental to applied research
Abstract
FAIR with its intense beams of ions and antiprotons provides outstanding and worldwide unique experimental conditions for extreme matter research in atomic and plasma physics and for application oriented research in biophysics, medical physics and materials science. The associated research programs comprise interaction of matter with highest electromagnetic fields, properties of plasmas and of solid matter under extreme pressure, density, and temperature conditions, simulation of galactic cosmic radiation, research in nanoscience and charged particle radiotherapy. A broad variety of APPA-dedicated facilities including experimental stations, storage rings, and traps, equipped with most sophisticated instrumentation will allow the APPA community to tackle new challenges. The worldwide most intense source of slow antiprotons will expand the scope of APPA related research to the exciting field of antimatter.
... At the start of the measurement phase within the ESR cycle of the 124 Xe(p,γ) 125 Cs experiment, about 10 6 -10 7 fully stripped 124 Xe 54+ ions were stored in the ESR at five different low energies with momentum spread of ∆p/p ∼ 10 −5 . The beam passed through the hydrogen gas jet target 2.5 · 10 5 -5 · 10 5 times per second resulting in peak luminosities of 10 26 cm −2 s −1 [9]. ...
... One double sided silicon strip detector (DSSSD) was placed at the end of the first dipole (at ∼ 53.5°from 60°bending angle) after focusing quadrupole duplett and the gas jet target. The position allows the spatial separation 125 Cs reaction has been successfully measured at five different center-of-mass energies from 8 MeV down to 5.5 MeV approaching the Gamow window of the reaction within less than 100 keV. Therefore, the applicability of the method is proven for heavier nuclides at the astrophysically relevant energies. ...
... The cross section of the 124 Xe(p,γ) 125 Cs reaction has been successfully measured for five different center-of-mass energies between 8 MeV and 5.5 MeV with uncertainties on the order of 10 %. The upper edge of the Gamow-window of this reaction was approached within <100 keV [136] proving the applicability of the method for heavier nuclides in astrophysically relevant energy ranges. ...
The cross sections of proton-capture reactions are extremely important to model explosive nucleosynthesis, in particular for the poorly understood production of the rare p-nuclei. Taking advantage of the unique possibilities at the Experimental Storage Ring (ESR) at GSI, the so-called proton-capture campaign has been started in 2009 focusing on the study of (p,γ) reactions for hot, explosive stellar scenarios. In this thesis, the recent experiment of the campaign, performed in March 2020, is analyzed and discussed in detail. The (p,γ) and (p,n) reaction cross-sections have been successfully measured at 10 MeV/u using a stable 124Xe ion beam and for the first time also using a radioactive ion beam, namely 118Te with 6 days half-life. In addition, a novel experimental scheme to improve the sensitivity of the method has been developed. Using the stable 124Xe beam it is demonstrated that the application of this new technique enables measurement at maximum sensitivity for proton-induced reactions in inverse kinematics.
... Status. The international Facility for Antiproton and Ion Research FAIR [200][201][202], currently under construction, will allow for a broad variety of experiments over a wide ranges of ion energy and ion intensity. The intensities can be varied from single ions up to highest particle densities at energies ranging from rest in the laboratory up to the highly relativistic collision domain, corresponding to the strongest and shortest electromagnetic field pulses available. ...
... In order to cope with these challenges, the SPARC collaboration (Stored Particle Atomic physics Research Collaboration) has been formed. SPARC has over 430 members and is dedicated to scientifically exploit the unique discovery potential of FAIR [201,202], in close interaction between experiment and theory. ...
... More specifically, Figure 30. Main FAIR facilities for storage and trapping within the SPARC collaboration, covering more than 10 orders of magnitude in particle kinetic energies [202]. Reprinted from [202], Copyright 2015, with permission from Elsevier. ...
We publish three Roadmaps on photonic, electronic and atomic collision physics in order to celebrate the 60th anniversary of the ICPEAC conference. Roadmap III focusses on heavy particles: with zero to relativistic speeds. Modern theoretical and experimental approaches provide detailed insight into the wide range of many-body interactions involving projectiles and targets of varying complexity ranging from simple atoms, through molecules and clusters, complex biomolecules and nanoparticles to surfaces and crystals. These developments have been driven by technological progress and future developments will expand the horizon of the systems that can be studied. This Roadmap aims at looking back along the road, explaining the evolution of the field, and looking forward, collecting nineteen contributions from leading scientists in the field.
... Status. The international Facility for Antiproton and Ion Research FAIR [200][201][202], currently under construction, will allow for a broad variety of experiments over a wide ranges of ion energy and ion intensity. The intensities can be varied from single ions up to highest particle densities at energies ranging from rest in the laboratory up to the highly relativistic collision domain, corresponding to the strongest and shortest electromagnetic field pulses available. ...
... In order to cope with these challenges, the SPARC collaboration (Stored Particle Atomic physics Research Collaboration) has been formed. SPARC has over 430 members and is dedicated to scientifically exploit the unique discovery potential of FAIR [201,202], in close interaction between experiment and theory. ...
... More specifically, Figure 30. Main FAIR facilities for storage and trapping within the SPARC collaboration, covering more than 10 orders of magnitude in particle kinetic energies [202]. Reprinted from [202], Copyright 2015, with permission from Elsevier. ...
We publish three Roadmaps on photonic, electronic and atomic collision physics in order to celebrate the 60th anniversary of the ICPEAC conference. Roadmap III focusses on heavy particles: with zero to relativistic speeds. Modern theoretical and experimental approaches provide detailed insight into the wide range of many-body interactions involving projectiles and targets of varying complexity ranging from simple atoms, through molecules and clusters, complex biomolecules and nanoparticles to surfaces and crystals. These developments have been driven by technological progress and future developments will expand the horizon of the systems that can be studied. This Roadmap aims at looking back along the road, explaining the evolution of the field, and looking forward, collecting nineteen contributions from leading scientists in the field.
... The science at FAIR is organized within four research pillars including CBM (Compressed Baryonic Matter), NUSTAR (NUclear STructure, Astrophysics, and Reactions), PANDA (antiProton ANnihilation at DArmstadt), and APPA (Atomic, Plasma Physics and Applications). APPA [125] has been formed to jointly coordinate and use synergies of mainly nonnuclear physics activities of the SPARC collaboration (atomic physics), the HED@FAIR collaboration (high energy density and plasma physics) and the application oriented BIOMAT collaboration. BIOMAT combines research activities of the biophysics and materials science communities and shares several experimental stations. ...
... Biological probes, different kind of materials, larger systems or even small satellites or spacecraft components can be tested. The BIOMAT station will be the main European ground-based facility for simulating cosmic radiation effects in the laboratory [125,134]. The very high penetration depth of FAIR beams has the advantages that bulk samples of mm-cm thickness can be completely irradiated for macroscopic material studies. ...
... This offers new opportunities for solving the two main hurdles toward the mitigation of the radiation risk problem in interplanetary missions: high uncertainty on late biological effects of heavy ions, and development of effective countermeasures. A large space radiation research program has been already planned at FAIR [125,134], in collaboration with ESA. ...
Applied nuclear physics is an essential part of the research activity at many particle accelerators. New, large accelerator facilities are currently under construction in Europe, Asia, and USA. These machines will be able to produce radioactive ion beams, and to increase the intensity and the energy of the heavy ions well beyond the limits currently available at the therapy or research facilities. The upcoming facilities open new opportunities for research in biomedical applications that require these special properties, such as particle radiography, radioactive beam imaging, ultra-high dose rates and new ions for therapy. Moreover, space radiation research and materials science can successfully exploit these new centers. The new facilities can pave the way to many future applications of nuclear physics for the benefit of the society. In this paper we will summarize the current status of applied sciences at high-energy accelerators, describe the characteristics of some of the machines under construction (FAIR, NICA, RAON, ELI) and discuss the new opportunities offered by these facilities in applied sciences.
... The combination of ESR, CRYRING and HITRAP will be complemented on the high-energy side by the High-Energy Storage Ring (HESR) [25], which is part of the FAIR project and which will extend the energy range towards high energies up to a few GeV/u. In this energy range, new effects of ions interacting with photons or electrons are expected [26]. An overview of the existing and future storage facilites at GSI and FAIR is given in Figure 1. ...
... All storage facilities are or will be equipped with several experimental installations, including a transverse gas-jet target and a facility for laser spectroscopy. This figure was reprinted from [26] (used by permission). ...
... The future research facility FAIR [24] will provide high-intensity beams of rare nuclides, for which high-precision X-ray spectroscopy will be an interesting subject in itself. In addition, once the Lamb Shift has been determined in stable isotopes with sufficient accuracy, the investigation of nuclear charge radii by means of the finite size contribution to the 1s Lamb Shift will be a particularly interesting subject [26,64], especially for rare or unstable nuclides. ...
X-ray spectroscopy of highly charged heavy ions is an important tool for the investigation of many topics in atomic physics. Such highly charged ions, in particular hydrogen-like uranium, are investigated at heavy ion storage rings, where high charge states can be produced in large quantities, stored for long times and cooled to low momentum spread of the ion beam. One prominent example is the determination of the 1s Lamb Shift in hydrogen-like heavy ions, which has been investigated at the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre for Heavy Ion Research. Due to the large electron binding energies, the energies of the corresponding photon transitions are located in the X-ray regime. To determine the transition energies with high accuracy, highly resolving X-ray spectrometers are needed. One concept of such spectrometers is the concept of microcalorimeters, which, in contrast to semiconductor detectors, uses the detection of heat rather than charge to detect energy. Such detectors have been developed and successfully applied in experiments at the ESR. For experiments at the Facility for Antiproton and Ion Research (FAIR), the Stored Particles and Atoms Collaboration (SPARC) pursues the development of new microcalorimeter concepts and larger detector arrays. Next to fundamental investigations on quantum electrodynamics such as the 1s Lamb Shift or electron–electron interactions in two- and three-electron systems, X-ray spectroscopy may be extended towards nuclear physics investigations like the determination of nuclear charge radii.
... The motionFPGA contains both analog and digital I/O and can be adapted to a variety of detection systems that deliver diverse forms of data, such as position in space, 1D motion traces, or externally pre-computed motion state information. Implemented motion mitigation strategies include conformal motion-synchronized dose delivery, gated delivery, and internal tumor volume [35] rescanning treatments. Tumor tracking, as described by Saito et al. [36], will be implemented for further motion mitigation studies. ...
... Both scanning magnets will be controlled by bipolar power supplies, and will be designed for a smaller inductivity, allowing for faster operation. The new system can be used later for the scanning system at the FAIR BIOMAT beamline [35], as the size of the magnet allows for scanning higher energy ions. The intensity control loop will be characterized and calibrated to achieve a stable and constant extracted intensity. ...
This article describes the updated GSI radiotherapy research facility (Cave M) located at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany. This facility was upgraded by modernizing the beamline that supported a pilot project in carbon ion cancer therapy in Europe from 1997 to 2008. Descriptions are provided of the modernized beamline, related hardware components and treatment delivery system. The performance specifications and general characteristics for each major component are described, along with example pre-clinical test results of selected components. These upgrades to Cave M allow for investigating novel therapy methods. The radiotherapy research facility is located on a beamline of the heavy ion synchrotron (Schwer-Ionen-Synchrotron, or SIS-18) accelerator complex, capable of delivering 0.1 to 2 GeV/u charged particle beams, ranging from protons to uranium. This beamline contains components for fast beam gating, aborting, focusing, scanning, monitoring, and shifting the range of the beam. The beam scanning magnets, position detectors, and beam monitors are described, along with tests of functionality and performance. A dose delivery system (DDS) was adapted from a clinical unit at the National Centre for Oncological Hadrontherapy (CNAO), Pavia, Italy, and consists of modular real-time hardware and software. The DDS was modified to enable research on adaptively-managed patient motion through the use of libraries of 4D-optimized radiation treatment plans, an unsolved problem of importance for treating moving tumors. The system is modular and is designed to support future research studies, such as high dose rate (Flash) radiotherapy and radioactive ion beams. A series of validation tests confirmed the functionality and performance of various key components and systems. For example, an end-to-end test revealed that dosimetric spatial homogeneity of over 95% was achieved for square treatment fields. More generally, all performance characteristics that were tested satisfied anticipated clinical requirements.
... During the last decade the development of Compton polarimeters within the Stored Particle Atomic Research Collaboration (SPARC) [24] was motivated by the fact that many atomic physics processes lead to the emission of polarized x rays and are in turn also strongly dependent on the polarization of the incoming particles [25,26]. Therefore, precise x-ray polarization measurements may offer new possibilities both for rigorous tests of atomic theory and also for the preparation and monitoring of polarized particle and photon beams, as was recently demonstrated for polarized electron beams [27][28][29] and for synchrotron radiation [30]. ...
... With the upcoming High-Energy Storage Ring (HESR) of the future FAIR facility, the range of accessible energies for atomic physics experiments on stored ion beams will be significantly extended up to a few GeV/u [49]. In particular, for the case of U 92+ a beam energy of up to 5 GeV/u will be possible [24]. ...
The radiative electron capture (REC) into the K shell of bare Xe ions colliding with a hydrogen gas target has been investigated. In this study, the degree of linear polarization of the K-REC radiation was measured and compared with rigorous relativistic calculations as well as with the previous results recorded for U92+. Owing to the improved detector technology, a significant gain in precision of the present polarization measurement is achieved compared to the previously published results. The obtained data confirms that for medium-Z ions such as Xe, the REC process is a source of highly polarized x rays which can easily be tuned with respect to the degree of linear polarization and the photon energy. We argue, in particular, that for relatively low energies the photons emitted under large angles are almost fully linear polarized.
... The latter is the research focus of the High Energy Density at FAIR collaboration (HED@FAIR), exploiting the unique properties of intense heavy ion pulses to heat matter volumetrically. More specifically, the planned HED@FAIR program aims on the EoS as well as on the transport properties of different materials in the so far widely unexplored regions of the phase diagram related to warm dense matter and high-energy density (HED) (see figure 16) [187][188][189][190][191][192]. ...
... The new high-energy facilities under construction in Europe, America, and Asia have plans for applied nuclear physics, especially toward atomic physics, plasma physics, material research, and medicine. APPA [187] is one of the four pillars of FAIR and its program covers several applications of high-energy heavy ion beams, including biomedical applications. Within the APPA cave ( figure 18), a beamline is dedicated to biophysics and material research (BIOMAT collaboration). ...
The Facility for Antiproton and Ion Research (FAIR) will be the accelerator-based flagship research facility in many basic sciences and their applications in Europe for the coming decades. FAIR will open up unprecedented research opportunities in hadron and nuclear physics, in atomic physics and nuclear astrophysics as well as in applied sciences like materials research, plasma physics and radiation biophysics with applications towards novel medical treatments and space science. FAIR is currently under construction as an international facility at the campus of the GSI Helmholtzzentrum for Heavy-Ion Research in Darmstadt, Germany. While the full science potential of FAIR can only be harvested once the new suite of accelerators and storage rings is completed and operational, some of the experimental detectors and instrumentation are already available and will be used starting in summer 2018 in a dedicated research program at GSI, exploiting also the significantly upgraded GSI accelerator chain. The current manuscript summarizes how FAIR will advance our knowledge in various research fields ranging from a deeper understanding of the fundamental interactions and symmetries in Nature to a better understanding of the evolution of the Universe and the objects within.
... The high-energy storage ring, HESR, will offer highly-charged ions at relativistic energies of up to γ=5-6. High-repetition laser systems are foreseen for coupling at the HESR [264]. When completed, the storage rings at GSI/FAIR will be able to provide extremely clean experimental conditions for a wide range of energy from tens of keV/u to several GeV/u [264]. ...
... High-repetition laser systems are foreseen for coupling at the HESR [264]. When completed, the storage rings at GSI/FAIR will be able to provide extremely clean experimental conditions for a wide range of energy from tens of keV/u to several GeV/u [264]. Furthermore, there are new proposals like for instance to install a low-energy storage ring at ISOLDE/CERN [265] or to construct a dedicated storage ring for studies of neutron-induced reactions in inverse kinematics, where a reactor core should be used as a target of free neutrons [266]. ...
The generation of dynamic high energy density plasmas in the pico- to nano-second time domain at high-energy laser facilities affords unprecedented nuclear science research possibilities. At the National Ignition Facility (NIF), the primary goal of inertial confinement fusion research has led to the synergistic development of a unique high brightness neutron source, sophisticated nuclear diagnostic instrumentation, and versatile experimental platforms. These novel experimental capabilities provide a new path to investigate nuclear processes and structural effects in the time, mass and energy density domains relevant to astrophysical phenomena in a unique terrestrial environment. Some immediate applications include neutron capture cross-section evaluation, fission fragment production, and ion energy loss measurement in electron-degenerate plasmas. More generally, the NIF conditions provide a singular environment to investigate the interplay of atomic and nuclear processes such as plasma screening effects upon thermonuclear reactivity. Achieving enhanced understanding of many of these effects will also significantly advance fusion energy research and challenge existing theoretical models.
... Currently, the GSI main linac for heavy ion research UNILAC is upgraded [6][7][8][9][10] for beam delivery to the Facility for Antiproton and Ion Research (FAIR) SIS100 [11] synchrotron and its various experimental areas, as APPA [12], CBM [13], HADES [14], NUS-TAR [15] and PANDA [16] among others (see Fig. 1). The new requirements for the beam are drastically different from the former demands, as the UNILAC will need to deliver a high peak-current beam at a low duty cycle. ...
In contrast to conventional E-mode resonance accelerators, H-mode DTLs provide for compact linac sections and have been established as highly efficient resonators during the last decades. Thus, H-mode structures are widely applied for heavy-ion acceleration with medium beam energies because of their outstanding capability to provide high acceleration gradients with relatively low energy consumption. To build upon those advantages, an alternating phase focusing beam dynamics layout has been applied to provide for a resonance accelerator design without internal lenses, which allows for eased commissioning, routine operation, maintenance, and potential future upgrades. The features of such a channel are going to be demonstrated on the example of two interdigital H-mode cavities, separated by an external quadrupole triplet. This setup provides for heavy ion (mass-to-charge ratio A / z ≤ 6 ) acceleration from 300 keV/u to 1400 keV/u and is used as an injector part of the superconducting continuous wave accelerator HELIAC. Hence, this promising approach generally enables effective and compact routine operation for various applications, such as super heavy ion research, material science, and radio biological applications such as heavy-ion tumor therapy.
... Moreover, beam cooling facilitates broad and rapidly developing research programs in atomic and nuclear physics. These can-not be covered here and the reader is referred to reviews [93][94][95][96][97][98][99][100][101][102][103] and references cited therein. ...
Decay properties known in neutral atoms can be altered significantly if all or most bound electrons are removed. Straightforwardly, in fully-ionised nuclei, the decay channels involving electrons are simply disabled. Also decay modes, that are hindered or completely blocked in neutral atoms, may, respectively, become dominant or open up in highly charged ions. Few-electron ions are by themselves clean systems with well-defined quantum numbers, in which the interactions within the remaining electrons can either be excluded or treated precisely, thereby allowing for investigations of the influence of atomic shell on nuclear decay properties. Violent stellar environments characterised by high temperatures and densities lead to high ionisation degrees of nuclides involved in nucleosynthesis processes. In spite of the rich motivation for studying radioactive decays of highly charged ions, intensive measurements became possible only after heavy-ion storage rings coupled to radioactive-ion beam facilities became available. Presented here is a compact review of the relevant experimental techniques and experiments.
... • Atomic, plasma physics and applications (APPA) The APPA collaboration has a rich programme which includes atomic physics research, plasma physics to study matter as on neutron star surfaces, and applied sciences such as particle therapy, space radiation effects and material science [6]. This will be achieved by using large variety of ion beam species, together with the storage rings and precision ion traps to be available at FAIR. ...
The Compressed Baryonic Matter (CBM) experiment is one of the major scientific pillars of the Facility for Antiproton and Ion Research (FAIR). The physics programme of CBM is centred around the exploration of the QCD phase diagram and nuclear matter equation-of-state in the region of high baryon densities. The respective rare probes will be accessed by using nucleus-nucleus collisions in the energy range √s NN = 2.9 - 4.9 GeV at peak interaction rates of up to 10 MHz and a trigger-less data acquisition scheme. This article reviews CBM physics goals with the experimental observables. The progress and current status of the comprising detector sub-systems, including their performance in FAIR Phase-0 experiments will also be presented.
... In addition, the strain rates found with such HED driver are lower than those of the more-commonly-used laser-driven shocks such that spatially uniform HED states in local thermodynamical equilibrium over cubic-mm samples can be obtained. For this reason, a dedicated target station in the multi-purpose APPA cave 45 is being foreseen, where the LAPLAS setup will be installed. ...
Diamonds are supposedly abundantly present in different objects in the Universe including meteorites, carbon-rich stars as well as carbon-rich extrasolar planets. Moreover, the prediction that in deep layers of Uranus and Neptune, methane may undergo a process of phase separation into diamond and hydrogen, has been experimentally verified. In particular, high power lasers have been used to study this problem. It is therefore important from the point of view of astrophysics and planetary physics, to further study the production processes of diamond in the laboratory. In the present paper, we present numerical simulations of implosion of a solid carbon sample using an intense uranium beam that is to be delivered by the heavy ion synchrotron, SIS100, that is under construction at the Facility for Antiprotons and Ion Research (FAIR), at Darmstadt. These calculations show that using our proposed experimental scheme, one can generate the extreme pressure and temperature conditions, necessary to produce diamonds of mm ³ dimensions.
... This unique combination of the most advantageous features, i.e. combing the most advantageous features of semiconductor detectors and crystal spectrometers, makes microcalorimeters a particularly promising type of detector system for the scientific program of the SPARC collaboration [9,25,26]. SPARC focuses on research in the realm of atomic, quantum, and fundamental physics at GSI and FAIR 7 , with a particular focus on precision x-ray spectroscopy. Within the collaboration, two microcalorimeter designs have recently been developed, namely the SIM-X detector [27], which is based on a compensated-doped silicon thermistor, and the maXs detector (Micro-Calorimeter Arrays for High Resolution x-ray Spectroscopy, [28]), which is a magnetic microcalorimeter (MMC). ...
We report on the first integration of novel magnetic microcalorimeter detectors (MMCs), developed within SPARC (Stored Particles Atomic Physics Research Collaboration), into the experimental environment of storage rings at GSI ⁶ ⁶ GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64 291 Darmstadt.
, Darmstadt, namely at the electron cooler of CRYRING@ESR. Two of these detector systems were positioned at the 0° and 180° view ports of the cooler section to obtain high-resolution x-ray spectra originating from a stored beam of hydrogen-like uranium interacting with the cooler electrons. While previous test measurements with microcalorimeters at the accelerator facility of GSI were conducted in the mode of well-established stand-alone operation, for the present experiment we implemented several notable modifications to exploit the full potential of this type of detector for precision x-ray spectroscopy of stored heavy ions. Among these are a new readout system compatible with the multi branch system data acquisition platform of GSI, the synchronization of a quasi-continuous energy calibration with the operation cycle of the accelerator facility, as well as the first exploitation of the maXs detectors’ time resolution to apply coincidence conditions for the detection of photons and charge-changed ions.
... An additional storage ring, RESR, between the CR and HESR, is foreseen at a later stage of FAIR to achieve a more efficient beam accumulation. Two 0 • laser-ion intersection regions are being prepared in the HESR [25,[56][57][58]. A similar scheme will be possible to realize at the HIAF facility under construction in China [27]. ...
{229}^{229}^{229}^{229}^{229}^{229}^{229}^{229}$Pa. The present discussion shall facilitate the relevant experimental efforts as well as affect the concepts of future trapping and storage facilities.
... At Stockholm, CRYRING has provided pioneering results over many years [6][7][8][9] and was recently further optimized for future experiments with heavy bare and few-electron ions, exotic nuclei, and antiprotons at FAIR [43]. At FAIR, CRYRING@ESR is an important part of a portfolio for trapping and storage facilities for cooled highly charged heavy ions bridging an energy range over more than 10 orders of magnitude, spanning from rest in the laboratory up to highly relativistic energies [44]. In combination with the ESR storage ring, CRYRING offers unique opportunities for a broad range of experiments with the heaviest electroncooled one-and few-electron ions at low energies [45]. ...
For decelerated bare lead ions at a low beam energy of 10 MeV/u, the x-ray emission associated with radiative recombination (RR) at threshold energies has been studied at the electron cooler of CRYRING@ESR at GSI, Darmstadt. In our experiment, we observed the full x-ray emission pattern by utilizing dedicated x-ray detection chambers installed at 0 • and 180 • observation geometry. Most remarkably, no line distortion effects due to delayed emission are present in the well-defined x-ray spectra, spanning a wide range of x-ray energies (from about 5 to 100 keV), which enables us to identify fine-structure resolved Lyman, Balmer, and Paschen x-ray lines along with the RR transitions into the K, L, and M shells of the ions. For comparison with theory, an elaborate theoretical model is established taking into account the initial population distribution via RR for all atomic levels up to Rydberg states with principal quantum number n = 165 in combination with time-dependent feeding transitions. Within the statistical accuracy, the experimental data are in very good agreement with the results of rigorous relativistic predictions. Most notably, this comparison sheds light on the contribution of prompt and delayed x-ray emission (up to 70 ns) to the observed x-ray spectra, originating in particular from yrast transitions into inner shells.
... On the experiment side, heavy-ion storage rings offer flexible conditions regarding the collision systems where intense beams of basically any element in a selected charge state can be provided for collisions with any gaseous internal target [33]. With the commissioning of FAIR, such highly charged ion beams will be available in a broad range of energies from basically at rest up to a few GeV/u [34]. The developed here methodology is important for guiding current as well as future experiments. ...
A fully relativistic approach is presented for the calculation of the bremsstrahlung emitted by an electron scattered off an ionic target. The ionic target is described as a combination of a nuclear electrostatic potential and a screening potential induced by the electronic cloud of the ion. The approach allows us to investigate the influence of the target electrons on the properties of the emitted radiation. We calculate the double differential cross section and Stokes parameters of the bremsstrahlung of an electron scattered off uranium ions in different charge states, ranging from bare to neutral uranium. Results on the high-energy endpoint of the electron bremsstrahlung from Li-like uranium ions U89+ are compared to the recent experimental data. For this process, it is found that taking into account the screening effect leads to a change of the cross section on the level of 14%, which can, in principle, be seen in present-day experiments.
... At Stockholm, CRYRING has provided pioneering results over many years [6][7][8][9] and has recently been further optimized for future experiments with heavy bare and few-electron ions, exotic nuclei as well as for anti-protons at FAIR [36]. At FAIR, CRYRING@ESR is an important part of a portfolio for trapping and storage facilities for cooled highlycharged heavy ions bridging an energy range over more than 10 orders of magnitude, spanning from rest in the laboratory up to highly relativistic energies [37]. In combination with the ESR storage ring, CRYRING offers unique opportunities for a broad range of experiments with electron cooled heaviest one-and few-electron ions at low energies [38]. ...
For bare lead ions, decelerated to the low beam energy of 10 MeV/u, the x-ray emission associated with radiative recombination (RR) at "cold collision" conditions has been studied at the electron cooler of CRYRING@ESR at GSI-Darmstadt. Utilizing dedicated x-ray detection chambers installed at 0{\deg} and 180{\deg} observation geometry, we observed for the very first time for stored ions the full x-ray emission spectrum associated with RR under electron cooling conditions. Most remarkably, no line distortion effects due to delayed emission are present in the well resolved spectra, spanning over a wide range of x-ray energies (from about 5 to 100 keV) which enable to identify fine-structure resolved Lyman, Balmer as well as Paschen x-ray lines along with the RR transitions into the K-, L and M-shell of the ions. To compare with theory, an elaborate theoretical model has been applied. By considering the relativistic atomic structure of Pb, this model is based on a sophisticated computation of the initial population distribution via RR for all atomic levels up to Rydberg states with principal quantum number n= 165 in combination with cascade calculations based on time-dependent rate equations. Within the statistical accuracy, the experimental x-ray line emission is in very good agreement with the results of the theoretical model applied. Most notably, this comparison sheds light on the contribution of prompt and delayed X-ray emission (up to 70 ns) to the observed X-ray spectra, originating in particular from Yrast transitions into inner shells.
... On the experiment side, heavy-ion storage rings offer flexible conditions regarding the collision systems where intense beams of basically any element in a selected charge state can be provided for collisions with any gaseous internal target [33]. With the commissioning of FAIR, such highly charged ion beams will be available in a broad range of energies from basically at rest up to a few GeV/u [34]. The developed here methodology is important for guiding current as well as future experiments. ...
A fully relativistic approach is presented for the calculation of the bremsstrahlung emitted by an electron scattered off an ionic target. The ionic target is described as a combination of an effective Coulomb potential and a finite-range potential induced by the electronic cloud of the ion. The approach allows us to investigate the influence of the electronic structure of the target on the properties of the emitted radiation. We calculate the double differential cross-section and Stokes parameters of the bremsstrahlung of an electron scattered off uranium ions in different charge states, ranging from bare to neutral uranium. Results on the high-energy endpoint of the electron bremsstrahlung from Li-like uranium ions are compared to the recent experimental data. For this process, it is found that taking into account the electronic structure of the target results in modification of the cross-section on the level of 14%, which can, in principle, be seen in present-day experiments.
... After commissioning of the SIS100 synchrotron, helium cross sections can be measured additionally at very high energies (E < 10 GeV/n), relevant for space radiation research. A suitable irradiation site will be at the BIOMAT beamline in the APPA Cave [133]. ...
The helium ( 4 He) component of the primary particles in the galactic cosmic ray spectrum makes significant contributions to the total astronaut radiation exposure. 4 He ions are also desirable for direct applications in ion therapy. They contribute smaller projectile fragmentation than carbon ( 12 C) ions and smaller lateral beam spreading than protons. Space radiation protection and ion therapy applications need reliable nuclear reaction models and transport codes for energetic particles in matter. Neutrons and light ions ( 1 H, 2 H, 3 H, 3 He, and 4 He) are the most important secondary particles produced in space radiation and ion therapy nuclear reactions; these particles penetrate deeply and make large contributions to dose equivalent. Since neutrons and light ions may scatter at large angles, double differential cross sections are required by transport codes that propagate radiation fields through radiation shielding and human tissue. This work will review the importance of 4 He projectiles to space radiation and ion therapy, and outline the present status of neutron and light ion production cross section measurements and modeling, with recommendations for future needs.
... Research activity at FAIR is structured into four pillars: NuSTAR, CBM, PANDA, and APPA. APPA deals with applied research (biophysics and materials research) and atomic and plasma physics [41]. FAIR is a user facility, and research is proposed by collaborations. ...
Biomedical applications at high-energy particle accelerators have always been an important section of the applied nuclear physics research. Several new facilities are now under constructions or undergoing major upgrades. While the main goal of these facilities is often basic research in nuclear physics, they acknowledge the importance of including biomedical research programs and of interacting with other medical accelerator facilities providing patient treatments. To harmonize the programs, avoid duplications, and foster collaboration and synergism, the International Biophysics Collaboration is providing a platform to several accelerator centers with interest in biomedical research. In this paper, we summarize the programs of various facilities in the running, upgrade, or construction phase. © Copyright © 2020 Patera, Prezado, Azaiez, Battistoni, Bettoni, Brandenburg, Bugay, Cuttone, Dauvergne, de France, Graeff, Haberer, Inaniwa, Incerti, Nasonova, Navin, Pullia, Rossi, Vandevoorde and Durante.
... Each additional energy has to be checked and reoptimized by hand. Even though SIS-18 and FAIR [20,21] are technically capable to follow the active approach as used at NSRL, the amount of setup time for all needed ion and energy combinations is not realistic for a multi-user experimental accelerator especially during the construction of FAIR with limited available beam time. ...
Space radiation is acknowledged as one of the main health risks for human exploration of the Solar system. Solar particle events (SPE) and the galactic cosmic radiation (GCR) can cause significant early and late morbidity, and damage mission critical microelectronics. Systematic studies of the interaction of energetic heavy ions with biological and electronic systems are typically performed at high-energy particle accelerators with a small subset of ions and energies in an independent and serialized way. This simplification can lead to inaccurate estimations of the harmful radiation effects of the full space radiation environment on man and machine. To mitigate these limitations, NASA has developed an irradiation system at the Brookhaven National Laboratory able to simulate the full GCR spectrum. ESA is also investing in ground-based space radiation studies in Europe, using the current and future facilities at GSI/FAIR in Darmstadt (Germany). We describe here an advanced hybrid active-passive space radiation simulation system to simulate GCR or SPE spectra. A predefined set of different monoenergetic 56Fe beams will be fired on specially designed beam modulators consisting of filigree periodic structures. Their thickness, composition and geometry per used primary beam energy are optimized via 1D-transport calculations in such a way that the superposition of the produced radiation fields at the target position closely simulate the GCR in different scenarios. The highly complex modulators will be built using state-of-the-art manufacturing techniques like 3D-printing and precision casting. A Monte Carlo simulation of the spectrum produced in this setup is reported.
... A new FRS (super-FRS) will be built at SIS100 [90], to accommodate the ambitious physics program of the NuSTAR collaboration [91]. In addition to the nuclear physics program, FAIR also includes a large applied physics program (APPA) in atomic physics, plasma physics, materials research, and biophysics [92]. The biophysics program at FAIR aims at exploiting the intensity and energy upgrades for therapy and space radiation protection research [93]. ...
Heavy ion therapy can deliver high doses with high precision. However, image guidance is needed to reduce range uncertainty. Radioactive ions are potentially ideal projectiles for radiotherapy because their decay can be used to visualize the beam. Positron-emitting ions that can be visualized with PET imaging were already studied for therapy application during the pilot therapy project at the Lawrence Berkeley Laboratory, and later within the EULIMA EU project, the GSI therapy trial in Germany, MEDICIS at CERN, and at HIMAC in Japan. The results show that radioactive ion beams provide a large improvement in image quality and signal-to-noise ratio compared to stable ions. The main hindrance toward a clinical use of radioactive ions is their challenging production and the low intensities of the beams. New research projects are ongoing in Europe and Japan to assess the advantages of radioactive ion beams for therapy, to develop new detectors, and to build sources of radioactive ions for medical synchrotrons.
... Stored particles can be accelerated or decelerated in the HESR with a ramp rate of 0.025 T/s to any energy which corresponds to the rigidity range 5 to 50 Tm. More recently the option to operate the HESR with ion beams was investigated [96,97]. In a similar way as with antiprotons the HESR can also be used for experiments with stored highly charged stable and/or radioactive isotope beams. ...
Storage rings have been employed over three decades in various kinds of nuclear and atomic physics experiments with highly charged ions. Storage ring operation and precision physics experiments benefit from the availability of beam cooling which is common to nearly all facilities. The basic aspects of the storage ring components and the operation of the ring in various ion-optical modes as well as the achievable beam conditions are described. Ion storage rings offer unparalleled capabilities for high precision experiments with stable and radioactive beams. The versatile techniques and methods for beam manipulations allow for preparing beams of highest quality at any energy of interest. The rings are therefore part of the experiment . Recent experiments conducted in a wide energy range and with various experimental installations are discussed. An overview of active and planned facilities, new experimental set-ups and proposed physics experiments completes this review.
... Stored particles can be accelerated or decelerated in the HESR with a ramp rate of 0.025 T/s to any energy which corresponds to the rigidity range 5 to 50 Tm. More recently the option to operate the HESR with ion beams was investigated [89,90]. In a similar way as with antiprotons the HESR can also be used for experiments with stored highly charged stable and/or radioactive isotope beams. ...
Storage rings have been employed over three decades in various kinds of nuclear and atomic physics experiments with highly charged ions. Storage ring operation and precision physics experiments benefit from the availability of beam cooling which is common to nearly all facilities. The basic aspects of the storage ring components and the operation of the ring in various ion-optical modes as well as the achievable beam conditions are described. Ion storage rings offer unparalleled capabilities for high precision experiments with stable and radioactive beams. The versatile techniques and methods for beam manipulations allow for preparing beams of highest quality at any energy of interest. The rings are therefore part of the experiment . Recent experiments conducted in a wide energy range and with various experimental installations are discussed. An overview of active and planned facilities, new experimental set-ups and proposed physics experiments completes this review.
... During the last decade the development of Compton polarimeters within the Stored Particle Atomic Research Collaboration (SPARC) [6] was motivated by the fact that many atomic physics processes lead to the emission of polarized x-rays and are in turn also strongly dependent on the polarization of the incoming particles [7,8]. Therefore, precise x-ray polarization measurements offer new possibilities both for rigorous tests of atomic theory and also for the preparation and monitoring of polarized particle and photon beams, as was recently demonstrated for polarized electron beams [9][10][11] and for synchrotron radiation [12]. ...
The radiative electron capture (REC) into the K shell of bare Xe ions colliding with a hydrogen gas target has been investigated. In this study, the degree of linear polarization of the K-REC radiation was measured and compared with rigorous relativistic calculations as well as with the previous results recorded for U. Owing to the improved detector technology a significant gain in precision of the present polarization measurement is achieved compared to the previously published results. The obtained data confirms that for medium-Z ions such as Xe the REC process is a source of highly polarized x-rays which can easily be tuned with respect to the degree of linear polarization and the photon energy. We argue, in particular, that for relatively low energies the photons emitted under large angles are almost fully linear polarized.
... The beams can be delivered to fixed-target experiments like CBM [651] or ring-based experiments like PANDA [652]. The experiments relevant for nuclear astrophysics are either under the umbrella of NUSTAR [653] or APPA [654] and can be fixed-target or ring-based [655]. ...
This is an exciting time for the study of r-process nucleosynthesis. Recently, a neutron star merger GW170817 was observed in extraordinary detail with gravitational waves and electromagnetic radiation from radio to γ rays. The very red color of the associated kilonova suggests that neutron star mergers are an important r-process site. Astrophysical simulations of neutron star mergers and core collapse supernovae are making rapid progress. Detection of both electron neutrinos and antineutrinos from the next galactic supernova will constrain the composition of neutrino-driven winds and provide unique nucleosynthesis information. Finally, FRIB and other rare-isotope beam facilities will soon have dramatic new capabilities to synthesize many neutron-rich nuclei that are involved in the r-process. The new capabilities can significantly improve our understanding of the r-process and likely resolve one of the main outstanding problems in classical nuclear astrophysics. However, to make best use of the new experimental capabilities and to fully interpret the results, a great deal of infrastructure is needed in many related areas of astronomy, astrophysics, and nuclear theory. We place these experiments in context by discussing astrophysical simulations and observations of r-process sites, observations of stellar abundances, galactic chemical evolution, and nuclear theory for the structure and reactions of very neutron-rich nuclei. This review paper was initiated at a three-week International Collaborations in Nuclear Theory program in June 2016, where we explored promising r-process experiments and discussed their likely impact, and their astronomical, astrophysical, and nuclear theory context.
We report on commissioning experiments at the high-energy, high-temperature (HHT) target area at the GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, combining for the first time intense pulses of heavy ions from the SIS18 synchrotron with high-energy laser pulses from the PHELIX laser facility. We demonstrate the use of X-ray diagnostic techniques based on intense laser-driven X-ray sources, which will allow probing of large samples volumetrically heated by the intense heavy-ion beams. A new target chamber as well as optical diagnostics for ion-beam characterization and fast pyrometric temperature measurements complement the experimental capabilities. This platform is designed for experiments at the future Facility for Antiproton and Ion Research in Europe GmbH (FAIR), where unprecedented ion-beam intensities will enable the generation of millimeter-sized samples under high-energy-density conditions.
We present in situ measurements of spectrally resolved X-ray scattering and X-ray diffraction from monocrystalline diamond samples heated with an intense pulse of heavy ions. In this way, we determine the samples’ heating dynamics and their microscopic and macroscopic structural integrity over a timespan of several microseconds. Connecting the ratio of elastic to inelastic scattering with state-of-the-art density functional theory molecular dynamics simulations allows the inference of average temperatures around 1300 K, in agreement with predictions from stopping power calculations. The simultaneous diffraction measurements show no hints of any volumetric graphitization of the material, but do indicate the onset of fracture in the diamond sample. Our experiments pave the way for future studies at the Facility for Antiproton and Ion Research, where a substantially increased intensity of the heavy ion beam will be available.
Th229 with a low-lying nuclear isomeric state is an essential candidate for a nuclear clock as well as many other applications. Laser excitation of the isomeric state has been a long-standing goal. With relativistic Th229 ions in storage rings, high-power lasers with wavelengths in the visible range or longer can be used to achieve high excitation rates of Th229 isomers. This can be realized through direct resonant excitation or excitation via an intermediate nuclear or electronic state, facilitated by the tunability of both the laser-beam and ion-bunch parameters. Unique opportunities are offered by highly charged Th229 ions due to the nuclear-state mixing. The significantly reduced isomeric-state lifetime corresponds to a much higher excitation rate for direct resonant excitation. Importantly, we propose electric dipole transitions changing both the electronic and nuclear states that are opened by the nuclear hyperfine mixing. We suggest using them for efficient isomer excitation in Li-like Th229 ions, via stimulated Raman adiabatic passage or single-laser excitation. We also propose schemes for probing the isomers, utilizing nuclear radiative decay or laser spectroscopy on electronic transitions, through which the isomeric-state energy can be determined with an orders-of-magnitude higher precision than the current value. The schemes proposed here for Th229 could also be adapted to low-energy nuclear states in other nuclei, such as Pa229.
The prospect of magnetoplasma compressor (MPC) due to their technical and geometrical characteristics are discussed, the formulation of ways to improve their parameters is obtained. Thermal modeling of radiation-magneto plasma dynamic processes of powerful electric discharge sources is presented. The developed mathematical model is based on a nonstationary axisymmetric two dimensional system of equations for viscous one-temperature radiation plasma dynamics. This paper presents results of the numerical calculation.
For photon energies from several 10 keV up to a few MeV Compton polarimetry is an indispensable tool to gain insight into subtle details of fundamental atomic radiative processes. Within the SPARC collaboration several segmented semiconductor detectors are developed that are well suited for application as efficient Compton polarimeters. In this report, these recent developments are reviewed and it is discussed how Compton polarimetry can be employed at the upcoming Gamma Factory.
This paper presents two-dimensional hydrodynamic simulations of implosion of a water sample, which is enclosed in a cylindrical shell of tungsten that is driven by an intense uranium beam. The considered beam parameters match the characteristics of the beam which will be delivered by the heavy ion synchrotron, SIS100, at the Facility for Antiprotons and Ion Research (FAIR). An experimental scheme based on this concept, which is named LAPLAS, is an important part of the high energy density physics research program at FAIR. The simulations show that the LAPLAS implosion leads to a low-entropy compression of water, which generates core conditions of water-rich planets. The importance of this work is underscored by the fact that more than 30% of the discovered extrasolar planets are Neptune-like water-rich planets. To be able to construct a reliable physical model of the formation and evolution of these planets, it is important to have correct understanding of the equation of state of the exotic states of water that exist in the planetary interior. It is thus expected that the knowledge obtained from the LAPLAS experiments will be a very valuable contribution to the field of planetary physics. We show that x-ray radiographic imaging using a high-intensity laser-driven hard x-ray source would be a suitable diagnostic capable of delivering high-resolution images of the hydrodynamic evolution.
Synopsis
We discuss the electron-optical properties of a toroidal magnetic sector spectrometer and its suitablilty for electron-positron pair spectroscopy in relativistic ion-atom collisions in the future HESR storage ring at FAIR. With the simultaneous mapping of electrons and positrons and geometric invariants in the lepton trajectorties this instrument offers a very high efficiency for studies of vector momentum correlation in free-free pair production.
This review concentrates on the specific properties and characteristics of damage structures generated with high-energy ions in the electronic energy loss regime. Irradiation experiments with so-called swift heavy ions (SHIs) find applications in many different fields, with examples presented in ion-track nanotechnology, radiation hardness analysis of functional materials, and laboratory tests of cosmic radiation. The basics of the SHI-solid interaction are described with special attention to processes in the electronic subsystem. The broad spectrum of damage phenomena is exemplified for various materials and material classes, along with a description of typical characterization techniques. This review also presents state-of-the-art modeling efforts that try to account for the complexity of the coupled processes of the electronic and atomic subsystems. Finally, a brief discussion at the end of this review on SHI phenomena induced by fission fragments in nuclear materials will highlight the relevance of energetic ion irradiation in nuclear technology applications.
The Facility for Antiproton and Ion Research (FAIR) will employ the World's highest intensity relativistic beams of heavy nuclei to uniquely create and investigate macroscopic (millimeter-sized) quantities of highly energetic and dense states of matter. Four principal themes of research have been identified: properties of materials driven to extreme conditions of pressure and temperature, shocked matter and material equation of state, basic properties of strongly coupled plasma and warm dense matter, and nuclear photonics with a focus on the excitation of nuclear processes in plasmas, laser-driven particle acceleration, and neutron production. The research program, principally driven by an international collaboration of scientists, called the [email protected] collaboration, will evolve over the next decade as the FAIR project completes and experimental capabilities develop. The first programmatic research element, called “FAIR Phase 0, officially began in 2018 to test components, detectors, and experimental techniques. Phase-0 research employs the existing and enhanced infrastructure of the GSI Helmholtzzentrum für Schwerionenforschung (GSI) heavy-ion synchrotron coupled with the PHELIX high-energy, high-intensity laser. The “FAIR Day one” experimental program, presently scheduled to begin in 2025, commences the use of FAIR's heavy-ion synchrotron, coupled to new experimental and diagnostic infrastructure, to realize the envisaged high-energy-density-science research program.
This contribution is based on the plenary presentation at the 14 th International Conference on Heavy Ion Accelerator Technology (HIAT-2018) in Lanzhou, China.
Heavy-ion storage rings offer unparalleled opportunities for precision experiments in the realm of nuclear structure, atomic physics and astrophysics. A brief somewhat biased review of the presently ongoing research programs is given as well as the future projects are outlined. The limited space does not allow for detailed description of individual experiments, which shall – to some extent – be compensated by extended bibliography.
We report an analysis of electron‐optical properties of a toroidal magnetic sector spectrometer and examine parameters for its implementation in a relativistic heavy‐ion storage ring, for example the High Energy Storage ring (HESR) at the future Facility for Antiproton and Ion Research (FAIR) facility. For studies of free–free pair production in heavy‐ion atom collisions, this spectrometer exhibits very high efficiencies for coincident e+–e− pair spectroscopy over a wide range of momenta of emitted lepton pairs. The high coincidence efficiency of the spectrometer is the key for stringent tests of theoretical predictions for the phase space correlation of lepton vector momenta in free–free pair production.
In this contribution we review the present status of experimental studies of electroweak decays of highly charged ions. A particular focus will be given on the bound state beta decay measurement of 205Tl.
The High Energy Storage Ring, HESR, will be constructed at the Facility for Antiproton and Ion Research, FAIR, Darmstadt. For the first time, it will be possible to perform experiments with cooled high-intensity stable and radioactive heavy ions at highly relativistic energies. To design experiments at the HESR, realistic estimations of beam lifetimes are indispensable. Here we report calculated cross sections and lifetimes for typical U⁸⁸⁺, U⁹⁰⁺, U⁹²⁺, Sn⁴⁹⁺ and Sn⁵⁰⁺ ions in the energy range E = 400 MeV/u–5 GeV/u, relevant for the HESR. Interactions with the residual gas and with internal gas-jet targets are also considered.
We investigate the quantum interference induced shifts between energetically close states in highly charged ions, with the energy structure being observed by laser spectroscopy. In this work, we focus on hyperfine states of lithiumlike heavy-Z isotopes and quantify how much quantum interference changes the observed transition frequencies. The process of photon excitation and subsequent photon decay for the transition 2s→2p→2s is implemented with fully relativistic and full-multipole frameworks, which are relevant for such relativistic atomic systems. We consider the isotopes Pb79+207 and Bi80+209 due to experimental interest, as well as other examples of isotopes with lower Z, namely Pr56+141 and Ho64+165. We conclude that quantum interference can induce shifts up to 11% of the linewidth in the measurable resonances of the considered isotopes, if interference between resonances is neglected. The inclusion of relativity decreases the cross section by 35%, mainly due to the complete retardation form of the electric dipole multipole. However, the contribution of the next higher multipoles (e.g., magnetic quadrupole) to the cross section is negligible. This makes the contribution of relativity and higher-order multipoles to the quantum interference induced shifts a minor effect, even for heavy-Z elements.
Present status of experimental studies of weak decays of highly charged ions is presented. The paper closely follows the progress-report presentation given at the conference. Due to the limited space an emphasis is given to an exhaustive bibliography.
The APPA R&D research collaboration at the international Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, is introduced and its activities are briefly summarized pointing out, in particular, the experimental program at the low-energy storage ring CRYRING which will become available for users already in 2018.
One of the aims of the SPARC collaboration [1] at FAIR is to perform precision atomic physics experiments with highly charged heavy ions at the High Energy Storage Ring (HESR). An internal target is indispensably an integral part for many such experiments. Ions with different charge states, which are obtained as a result of interaction of an ion beam with the target, need to be effectively separated and detected. In this work we present ion optical studies unambiguously showing the feasibility of SPARC experiments at the HESR.
Accurate spectroscopy of highly charged high-Z ions in a storage ring is demonstrated to be feasible by the use of specially adapted crystal optics. The method has been applied for the measurement of the 1s Lamb shift in hydrogen-like gold (Au 78+) in the ESR storage ring through spectroscopy of the Lyman x rays. This measurement represents the first result obtained for a high-Z element using high-resolution wavelength-dispersive spectroscopy in the hard x-ray regime, paving the way for sensitivity to higher-order QED effects.
On the basis of a double-side segmented Si(Li) crystal a new Compton polarimeter was developed within the SPARC collaboration. The new detector is equipped with a cryogenic first stage of the preamplifiers to improve the energy resolution compared to previous detectors with preamplifiers operating at room temperature. We present first results from a commissioning measurement of the new instrument at the ESR storage ring of GSI in Darmstadt, Germany and contrast it with the performance of an precursor polarimeter system.
We present the concluding result from an Ives-Stilwell-type time dilation experiment using 7Li+ ions confined at a velocity of β=v/c=0.338 in the storage ring ESR at Darmstadt. A Λ-type three-level system within the hyperfine structure of the 7Li+ 3S1→3P2 line is driven by two laser beams aligned parallel and antiparallel relative to the ion beam. The lasers’ Doppler shifted frequencies required for resonance are measured with an accuracy of < 4×10−9 using optical-optical double resonance spectroscopy. This allows us to verify the special relativity relation between the time dilation factor γ and the velocity β, γ 1 − β2 = 1 to within 2.3×10−9 at this velocity. The result, which is singled out by a high boost velocity β, is also interpreted within Lorentz invariance violating test theories.
One of the fundamental properties of the proton is its magnetic moment, µp. So far µp has been measured only indirectly, by analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in terms of the nuclear magneton: μp = 2.792847350(9)μN. This measurement outperforms previous Penning-trap measurements in terms of precision by a factor of about 760. It improves the precision of the forty-year-old indirect measurement, in which significant theoretical bound state corrections were required to obtain µp, by a factor of 3. By application of this method to the antiproton magnetic moment, the fractional precision of the recently reported value can be improved by a factor of at least 1,000. Combined with the present result, this will provide a stringent test of matter/antimatter symmetry with baryons.
The quest for the value of the electron's atomic mass has been the subject of continuing efforts over the past few decades. Among the seemingly fundamental constants that parameterize the Standard Model of physics and which are thus responsible for its predictive power, the electron mass me is prominent, being responsible for the structure and properties of atoms and molecules. It is closely linked to other fundamental constants, such as the Rydberg constant R∞ and the fine-structure constant α (ref. 6). However, the low mass of the electron considerably complicates its precise determination. Here we combine a very precise measurement of the magnetic moment of a single electron bound to a carbon nucleus with a state-of-the-art calculation in the framework of bound-state quantum electrodynamics. The precision of the resulting value for the atomic mass of the electron surpasses the current literature value of the Committee on Data for Science and Technology (CODATA) by a factor of 13. This result lays the foundation for future fundamental physics experiments and precision tests of the Standard Model.
High-pressure and high-temperature phases show unusual physical and chemical properties, but they are often difficult to 'quench' to ambient conditions. Here, we present a new approach, using bombardment with very high-energy, heavy ions accelerated to relativistic velocities, to stabilize a high-pressure phase. In this case, Gd(2)Zr(2)O(7), pressurized in a diamond-anvil cell up to 40 GPa, was irradiated with 20 GeV xenon or 45 GeV uranium ions, and the (previously unquenchable) cubic high-pressure phase was recovered after release of pressure. Transmission electron microscopy revealed a radiation-induced, nanocrystalline texture. Quantum-mechanical calculations confirm that the surface energy at the nanoscale is the cause of the remarkable stabilization of the high-pressure phase. The combined use of high pressure and high-energy ion irradiation provides a new means for manipulating and stabilizing new materials to ambient conditions that otherwise could not be recovered.
Isotope shifts in dielectronic recombination spectra were studied for Li-like (A)Nd(57+) ions with A=142 and A=150. From the displacement of resonance positions energy shifts deltaE(142 150)(2s-2p(1/2))=40.2(3)(6) meV [(stat)(sys)] and deltaE(142 150)(2s-2p(3/2))=42.3(12)(20) meV of 2s-2p(j) transitions were deduced. An evaluation of these values within a full QED treatment yields a change in the mean-square charge radius of (142 150)deltar(2)=-1.36(1)(3) fm(2). The approach is conceptually new and combines the advantage of a simple atomic structure with high sensitivity to nuclear size.
We report our observation of the resonant fluorescence from highly charged uranium ions. Using the resonant coherent excitation (RCE) technique, the 2s-2p3/2 transition in 191.68 MeV/u Li-like U89+ ions was excited at 4.5 keV with a resonance width of 4.4 eV. The result demonstrated that the RCE can be applied to resonant fluorescence spectroscopy of high-Z ions up to uranium with high efficiency and resolution.
Single and double ionization of helium by 1 GeV/nucleon U92+ impact was explored in a kinematically complete experiment. The relativistic ion generates a subattosecond (10(-18) s) superintense (I > 10(19) W/cm(2)) electromagnetic pulse, which is interpreted as a field of equivalent photons (Weizsacker-Williams method). Cross sections, the emission characteristics of ions and electrons as well as momentum balances, are quantitatively discussed in terms of photoionization of the atom in this broadband, ultrashort virtual photon field. [S0031-9007(97)04437-2].
The health risks of space radiation are arguably the most serious challenge to space exploration, possibly preventing these missions due to safety concerns or increasing their costs to amounts beyond what would be acceptable. Radiation in space is substantially different from Earth: high-energy (E) and charge (Z) particles (HZE) provide the main contribution to the equivalent dose in deep space, whereas rays and low-energy particles are major contributors on Earth. This difference causes a high uncertainty on the estimated radiation health risk (including cancer and noncancer effects), and makes protection extremely difficult. In fact, shielding is very difficult in space: the very high energy of the cosmic rays and the severe mass constraints in spaceflight represent a serious hindrance to effective shielding. Here the physical basis of space radiation protection is described, including the most recent achievements in space radiation transport codes and shielding approaches. Although deterministic and Monte Carlo transport codes can now describe well the interaction of cosmic rays with matter, more accurate double-differential nuclear cross sections are needed to improve the codes. Energy deposition in biological molecules and related effects should also be developed to achieve accurate risk models for long-term exploratory missions. Passive shielding can be effective for solar particle events; however, it is limited for galactic cosmic rays (GCR). Active shielding would have to overcome challenging technical hurdles to protect against GCR. Thus, improved risk assessment and genetic and biomedical approaches are a more likely solution to GCR radiation protection issues.
Using a new experimental approach, fission-track formation has been simulated, for the first time, under crustal conditions by exposing natural zircon, at a pressure of 7.5 kbar and a temperature of 250 °C, to a beam of relativistic heavy ions. The latent tracks were investigated using high-resolution transmission electron microscopy, and the diameters of several hundred tracks were measured. The mean values (± σ) of the track diameters were 5.2 ± 0.5 nm and 5.4 ± 0.4 nm for zircon at ambient and elevated pressure-temperature, respectively. Based on the number of measurements, this represents a statistically significant difference between the tracks at ambient vs. high-pressure/temperature conditions. The slightly larger size of the tracks at elevated pressure can be understood in terms of the increased efficiency of the damage process in a strained crystal lattice. This slight variation in track diameter (~ 0.2 nm) at high pressure probably will not affect the dimensions of etched tracks.
Intense heavy ion beams open new possibilities in high-energy-density matter research. Due to the unique feature of the energy deposition process of heavy ions in dense matter (volume character of heating) it is possible to generate high entropy states in matter without the necessity of shock compression. Previously, such high entropy states could only be achieved by using the most powerful shock wave generators, like nuclear explosions or powerful lasers. In this paper this novel technique of heavy ion heating and expansion is proposed to explore new fascinating regions of the phase diagram, including the liquid phase, the evaporation region with the critical point, and strongly coupled plasmas. (C) 2002 American Institute of Physics.
High-energy proton microscopy provides unique capabilities in penetrating radiography including the combination of high spatial resolution and field-of-view, dynamic range of density for measurements, and reconstructing density variations to less than 1% inside volumes and in situ environments. We have recently proposed to exploit this novel proton radiography technique for image-guided stereotactic particle radiosurgery. Results of a first test for imaging biological and tissue-equivalent targets with high-energy (800 MeV) proton microscopy are presented here. Although we used a proton microscope setup at ITEP (Moscow, Russia) optimized for fast dynamic experiments in material research, we could reach a spatial resolution of 150 μm with approximately 10(10) protons per image. The potential of obtaining high-resolution online imaging of the target using a therapeutic proton beam in the GeV energy region suggests that high-energy proton microscopy may be used for image-guided proton radiosurgery.
The recombination of a free electron into a bound state of bare, heavy nucleus under simultaneous production of bound-electron--free-positron pair is studied within the framework of relativistic first--order perturbation theory. This process, denoted as "negative-continuum dielectronic recombination" leads to a formation of not only the ground but also the singly- and doubly-excited states of the residual helium-like ion. The contributions from such an excited--state capture to the total as well as angle-differential cross-sections are studied in detail. Calculations are performed for the recombination of (initially) bare uranium U ions and for a wide range of collision energies. From these calculations, we find almost 75 % enhancement of the total recombination probability if the excited ionic states are taken into account. Comment: 8 pages, 4 figures, accepted to PRA
Employing a two-dimensional simulation model, this paper presents a suitable design for an experiment to study metallization of hydrogen in a heavy-ion beam imploded multilayered cylindrical target that contains a layer of frozen hydrogen. Such an experiment will be carried out at the upgraded heavy-ion synchrotron facility (SIS-18) at the Gesellschaft für Schwerionenforschung, Darmstadt by the end of the year 2001. In these calculations we consider a uranium beam that will be available at the upgraded SIS-18. Our calculations show that it may be possible to achieve theoretically predicted physical conditions necessary to create metallic hydrogen in such experiments. These include a density of about 1 g/cm(3), a pressure of 3-5 Mbar, and a temperature of a few 0.1 eV.
X-ray spectra following radiative recombination of free electrons with bare uranium ions (U92+) were measured at the electron cooler of the ESR storage ring. The most intense lines observed in the spectra can be attributed to the characteristic Lyman ground-state transitions and to the recombination of free electrons into the K shell of the ions. Our experiment was carried out by utilizing the deceleration technique which leads to a considerable reduction of the uncertainties associated with Doppler corrections. This, in combination with the 0 degree observation geometry, allowed us to determine the ground-state Lamb shift in hydrogenlike uranium (U91+) from the observed x-ray lines with an accuracy of 1%. The present result is about 3 times more precise than the most accurate value available up to now and provides the most stringent test of bound-state quantum electrodynamics for one-electron systems in the strong-field regime.
In many solids, heavy ions of high kinetic energy (MeV-GeV) produce long cylindrical damage trails with diameters of order 10 nm. Up to now, no information was available how solids cope with the simultaneous exposure to these energetic projectiles and to high pressure. We report the first experiments where relativistic uranium and gold ions from the SIS heavy-ion synchrotron at GSI were injected through several mm of diamond into solid samples pressurized up to 14 GPa in a diamond anvil cell. In synthetic graphite and natural zircon, the combination of pressure and ion beams triggered drastic structural changes not caused by the applied pressure or the ions alone. The modifications comprise long-range amorphization of graphite rather than individual track formation, and in the case of zircon the decomposition into nanocrystals and nucleation of the high-pressure phase reidite.
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