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.

The high-energy/high-intensity laser facility PHELIX of the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt,Germany,has been in operation since 2008.Here,we review the current system performance,which is the result of continuous development and further improvement.Through its versatile frontend architecture,PHELIX can be operated in both long-and short-pulse modes,corresponding to ns-pulses with up to 1 kJ pulse energy and sub-ps,200 J pulses,respectively.In the short-pulse mode,the excellent temporal contrast and the control over the wavefront make PHELIX an ideal driver for secondary sources of high-energy ions,neutrons,electrons and X-rays.The long-pulse mode is mainly used for plasma heating,which can then be probed by the heavy-ion beam of the linear accelerator of GSI.In addition,PHELIX can now be used to generate X-rays for studying exotic states of matter created by heavy-ion heating using the ion beam of the heavy-ion synchrotron of GSI.

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.

PHELIX laser facility F. Wagner1,2, S. Bedacht3, C. P. João4, A. Ortner3, M. Roth3, T. Stöhlker1,2, A. Tauschwitz5 and V. Bagnoud1,2 1 GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany 2 Helmholtz Institute Jena, Jena, Germany 3 Technische Universität Darmstadt, Darmstadt, Germany 4 GoLP/IPFN Instituto Superior Técnico, Lisbon, Portugal 5Frankfurt University, Frankfurt, Germany

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.

The generation of intense ion beams from high-intensity laser-generated plasmas has been the focus of research for the last decade. In the LIGHT collaboration the expertise of heavy ion accelerator scientists and laser and plasma physicists has been combined to investigate the prospect of merging these ion beams with conventional accelerator technology and exploring the possibilities of future applications. We report about the goals and first results of the LIGHT collaboration to generate, handle and transport laser driven ion beams. This effort constitutes an important step in research for next generation accelerator technologies.

Laser-produced plasmas are often used as bright x-ray backlighters for time-resolved plasma diagnostics, but such backlighters simultaneously generate damaging electromagnetic pulse (EMP). A laser-driven Ar gas jet x-ray source has been measured with magnetic flux B-dot probes to produce 20 times ±37% less integrated EMP in the 0.5–2.5 GHz band than a solid chlorinated plastic foil, while retaining 85% of the laser to ≈3 keV x-ray conversion efficiency. These results are important for future backlighter development, since tailoring target density may provide a way to reduce EMP even as laser power increases.

A kilojoule-class laser (Raptor) has recently been activated at the Phoenix-laser-facility at the University of California Los Angeles (UCLA) for an experimental program on laboratory astrophysics in conjunction with the Large Plasma Device (LAPD). The unique combination of a high-energy laser system and the 18 meter long, highly-magnetized but current-free plasma will support a new class of plasma physics experiments, including the first laboratory simulations of quasi-parallel collisionless shocks, experiments on magnetic reconnection, or advanced laser-based diagnostics of basic plasmas. Here we present the parameter space accessible with this new instrument, results from a laser-driven magnetic piston experiment at reduced power, and a detailed description of the laser system and its performance.

Using a pulse power solenoid, we demonstrate efficient capture of laser accelerated proton beams and the ability to control their large divergence angles and broad energy range. Simulations using measured data for the input parameters give inference into the phase-space and transport efficiencies of the captured proton beams. We conclude with results from a feasibility study of a pulse power compact achromatic gantry concept. Using a scaled target normal sheath acceleration spectrum, we present simulation results of the available spectrum after transport through the gantry.

Thin C-foils heated with intense laser beams are used at the Z6 experimental area to investigate energy loss and charge state distribution of heavy ions in a plasma [1]. The presented calculations show the advantage of the 2-sided foil heating versus its 1-sided heating when the irradiating laser flux is spatially strongly non-uniform. Irradiation from two opposite sides can be realized by using the Phelix and the nhelix lasers. In the simulations we assumed that the beam parameters of both lasers are identical. The frequency doubled lasers have an intensity of 5 · 10 W/cm and are focused on a spot of 1 mm in diameter. The intensity distribution over the focal spot is ap proximated asFlas(x) = 1 + 0.5 cos(2πx/l), l = 50 μm. The laser pulse is 13 ns long, ramped with a 3 ns rise and fall times. Initially the C-foil has a mass thickness of 〈ρx〉 = 0.1 mg/cm. The simulations were done in the Cartesian(x, y) geometry. The laser beam is incident from the right along thex-axis, the foil is placed at x = 0. For the 2-sided heating the y-axis is treated as a reflective boundary and only half of the foil is considered. The simulations were done with the new radiation-hydrodynamics code RALEF-2D [2]. The equation of state, thermal conduction coefficients and LTE spectral opacities have been generated by the THERMOS code [3]. Figure 1 shows the linear density 〈ρx〉 as a function of y. The peaks of 〈ρx〉 correspond to the minima of the laser intensity. For the 1-sided heating the highest density vari ation occurs at = 3.5 ns, whereas byt = 9 ns the density distribution becomes almost uniform. For the 2-sided heating the corresponding times are 3 ns and 6.5 ns. Although for 1-sided heating the density variations are suppressed a t later times, the fully ionized plasma state, required for st pping measurements, is not achieved. Figure 2 compares the 2D distributions of the ionization degree Z at t = 5 ns for the 1-sided and 2-sided cases. The laser comes from the right, strong non-uniformities of Z are formed at the rear non-illuminated side. The profiles of Z along〈ρx〉 at y = 0.125 mm, t = 5 and 6.5 ns in the 2-sided case are shown in Fig. 3. It is seen that the plasma column becomes practically homogeneous and fully ionized by t = 6.5 ns, and, therefore, well suited for ion stopping measurements.

Preparatory work is presented in the context of the upcoming LIGHT project, which is dedicated to build up a test stand for injecting laser accelerated protons into conventional accelerator structures, located at GSI Helmholtzcenter for Heavy Ion Research (Darmstadt, Germany). In an experimental campaign in 2010, a beam of 8.4×10 9 protons with 170 ps pulse duration and (6.7±0.1) MeV particle energy could be focused with the use of a pulsed high-field solenoid. Collimation and transport of a 300 ps proton bunch containing 3×10 9 protons with (13.5±0.5) MeV particle energy over a distance of 407 mm was also demonstrated. Parallel simulation studies of the beam transport through the solenoid are in good agreement with the experiment.

A pulsed high field solenoid was used in a laser-proton acceleration experiment to collimate and transport the proton beam that was generated at the irradiation of a flat foil by a high intensity laser pulse. 1012 particles at an energy of 2.3 MeV could be caught and transported over a distance of more than 240 mm. Strong space charge effects occur, induced by the high field of the solenoid that forces all co-moving electrons down the the solenoid's axis, building up a strong negative space charge that interacts with the proton beam. This leads to an aggregation of the proton beam around the solenoid's axis and therefore to a stronger focusing effect. The collimation and transport of laser-accelerated protons is the first step to provide these unique beams for further applications like post-acceleration by conventional accelerator structures.

General overview PHELIX, a high-energy short-pulse laser, allows for combined ion-laser experiments to support the science programs of the Plasma Physics and Atomic Physics departments of GSI. 2009 was the first year of full nominal operation, in which the laser delivered high-energy pulses in the sub-kilojoule range to various target areas. In spite of its relatively low repetition rate, the 1000 documented shot was delivered near the end of the year. In 2009, PHELIX was used in combination with the ion beam. It was shot simultaneously with the nhelix laser to uniformly heat carbon foils to a plasma state, which was then probed using the ion beam from the UNILAC. This new setup led to a significant increase in the quality of the recorded data. Other experiments were done using the laser alone to study the generation of an x-ray laser at wavelengths shorter than 10 nm. In this experiment, a new setup yielded a reduction of the pump-laser energy, required to reach the lasing threshold, to values compatible with existing high repetition-rate facilities. This makes the setup ideally suited for high-average-energy short-wavelength x-ray laser systems. Another significant scientific result was obtained in proton acceleration by use of hemispherical targets. Here, a significant shift of the proton spectrum to higher energies was observed. Furthermore, about one third of the time was devoted to maintenance and improvements of the facility, which are reviewed in the last part of this report.

This article reports about controlling laser-accelerated proton beams with respect to beam divergence and energy. The particles are captured by a pulsed high field solenoid with a magnetic field strength of 8.6 T directly behind a flat target foil that is irradiated by a high intensity laser pulse. Proton beams with energies around 2.3 MeV and particle numbers of 1012 could be collimated and transported over a distance of more than 300 mm. In contrast to the protons the comoving electrons are strongly deflected by the solenoid field. They propagate at a submillimeter gyroradius around the solenoid’s axis which could be experimentally verified. The originated high flux electron beam produces a high space charge resulting in a stronger focusing of the proton beam than expected by tracking results. Leadoff particle-in-cell simulations show qualitatively that this effect is caused by space charge attraction due to the comoving electrons. The collimation and transport of laser-accelerated protons is the first step to provide these unique beams for further applications such as postacceleration by conventional accelerator structures.

Opacity measurements in warm dense matter (WDM) provide a valuable benchmark for the diverging theoretical models in this regime. Heating of thin foils with intense heavy-ion beams allows one to create isolated samples of warm dense matter suitable for experimental determination of frequency-dependent opacities. A prerequisite for the measurements is the isothermal expansion of the heated foil. Hydrodynamic simulations predict that this condition is fulfilled. The analysis shows that existing ion-beam accelerators are capable to contribute to this field of research.