Experiments using the high current upgrade of the GSI accelerators: Response of converters to heating by intense heavy ion beams

The high current upgrade of the accelerator facilities at GSI Darmstadt, Germany, has created possibilities for a new class of experiments with heavy ion beams. Intense pulses of heavy ions can rapidly heat converter targets to high temperatures. The hydrodynamic response of these converters, the temperature development and the emitted radiation are investigated experimentally. Moreover, measurements are compared to numerical simulations. In addition, the expansion of the converters can be employed to compress cryogenic solid hydrogen that is located next to the converters for fundamental research on the equation of state of hydrogen at high pressures. Due to the long range of the ions in the converters rather large volumes of hydrogen can be compressed homogeneously, allowing for high precision in the diagnostics. Various geometries for planar or radial compression are under discussion. With a 300 MeV/u ⁴⁰Ar¹⁸⁺ beam of 2 × 10¹⁰ particles and 400 μm radius (HWHM), delivered within a pulse of 300 ns width (FWHM), lead targets were brought to hydrodynamic expansion and collision. Maximum expansion velocities were 570 m/s. The numerical simulations yielded maximum temperatures of 0.17 eV and maximum pressures of 2.8 GPa in direct heating.