GSI (Darmstadt, Germany)

GSI Helmholtzzentrum für Schwerionenforschung

GSI Helmholtzzentrum für Schwerionenforschung is an accelerator laboratory hosting PHELIX (Petawatt High-Energy Laser for Ion eXperiments), a laser facility that permits presently two types of operation, one in the long-pulse regime (1 kJ/0.5-10 ns) and one in the short-pulse regime (200 J/0.5 ps), thanks to two dedicated frontends. The installation has some outstanding features, such as the high temporal contrast on the few-ps time scale, and its pulse-shaping capabilities of the ns pulse; in addition, synchronized operation of the two frontends enables introducing a controlled ns pre-pulse to tailor laser-plasma interaction at high intensity. PHELIX allows for either laser-only experiments in the Petawatt Target Area (PTA) or combined laser-accelerator experiments at the experiment areas Z6 and HHT. At the Z6 cave, PHELIX is coupled to the UNILAC ion beam for studying the interaction of swift ions with laser-generated plasmas. Alternatively, protons and light ions can be accelerated by PHELIX at Z6 and then transported and prepared (energy and temporal bunching, collimation) for user experiments. At the HHT cave, the PHELIX ns pulse is available, synchronized to the SIS18 heavy-ion beam, enabling the study of heavy-ion heated matter using laser-driven X-ray diagnostics.

 

Website:
GSI: www.gsi.de
PHELIX: www.gsi.de/work/forschung/appamml/plasmaphysikphelix/phelix

Contact: Vincent Bagnoud

 

Research highlights

Details of the PHELIX laser system

  • New developments and capabilities are described in [Zs. Major et al., HPLSE 12, e39 (2024)]

Secondary and radiation sources and theis applications

  • Laser-driven neutron are a promising tool for non-destructive and isotope-sensitive material analysis [Nature Commun. 13, 1173 (2022)]
  • Betatron radiation from laser-accelerated electron bunches in near-critical-density targets [Sci. Rep. 14, 14785 (2024)]
  • Using laser-driven ion bunches for stopping power experiments: the LIGHT (Laser Ion Generation, Handling and Transport) beamline [Journal of plasma physics 90, 905900302 (2024)]
  • Using laser-driven X-rays for grating-based phase-contrast imaging of laser-driven shock waves [Journal of Instrumentation 19, P05004 (2024), Matter and radiation at extremes 9, 047803 (2024)]
  • Understanding high-intensity laser plasma interaction by investigating the holeboring process in dense plasmas, [Nature Commun. 12, 6999 (2021)]

Combined laser / ion beam experiments

  • Experimental platform for studying heavy-ion heated matter using laser-driven X-rays and first X-ray diffraction-experiments [Matter Radiat. Extremes 10, 017803 (2025); Matter Radiat. Extremes 9, 047802 (2024)]
Expertise

In the laser standalone target area, the PW-class capabilities of PHELIX have been employed for particle beam and X-ray generation experiments over more than 15 years with many different target and laser-beam combinations. In addition to laser-only experiments that focus on driving secondary sources of particles and X-rays, the unique laser-accelerator combinations allow to study heavy-ion-heated warm dense matter using laser-driven X-ray diagnostics. Broadband incoherent pulses will be available in the near future, which will give access to the investigation and mitigation of laser-plasma instabilities, a crucial question in laser-driven fusion research. The LIGHT (Laser Ion Generation, Handling and Transport) experimental beamline installation allows the combination of laser-accelerated ions and conventional accelerator structures.

Equipment offered to external users

Please refer to the PHELIX website to see the current laser and experimental parameters.

As of February 2025:

Laser Energy: the energy of the laser is adjusted depending on the configuration
  • At PTA, short pulses with up to 140 J in combination with an f = 40 cm, 45° parabola are available.
  • At PTA, short pulses with up to 70 J in combination with an f =150 cm, 90° parabola are available.
  • At Z6, long (1 – 10 ns) pulses with an energy of about 180 J (depending on pulse length) at 527 nm are available with an f = 4 m focusing lens. Two random phase plates creating top-hat foci of 1 mm or 0.5 mm diameter are available.
  • At Z6, short pulses of 15 J at 1054 nm and a pulse duration of 500 fs are also available but not in parallel with the nanosecond beam.
  • At HHT, long pulses (1 – 10 ns) with an energy up to 200 J (on best effort basis and depending on pulse length, for example: max. 200 J in 2 ns.) at 527 nm are available with an f = 1.8 m focusing lens (F/13). Main focal spot 20 µm (FWHM), most of the energy contained in ~60 µm diameter spot. A random phase plate can be used to generate a more uniform focus of 150 μm diameter.
Pulse profiles
  • The pulse duration at PHELIX is 500 fs by default. The pulse duration can be stretched to a few ps with on-line measurement. Above 3 ps, the pulse duration is set and calibrated off-line, but cannot be verified on-line.
  • The temporal contrast of PHELIX is 10-11 (10-12 best effort). It is verified offline before every beam time.
  • A programmable nanosecond front-end allows for pulses with a deterministic pulse profile with 250 ps resolution within a 10 ns window. The pulse length must not be shorter than 1.5 ns.
  • At PTA, a combination of the long and the short pulse can be requested to introduce a fully controllable pedestal. However, the timing jitter between the two frontends will be at least +/- 200 ps (peak-to-peak).
Further remarks
  • At PTA, it is possible to introduce apertures to create a double beam. In such a case, the energy cannot exceed 30 J per beam.
  • At Z6, a VISAR system (660 nm, 40 ns) is available.