The internal gas-jet target of the ESR storage ring currently provides typical target densities from 10¹¹ up to 10¹⁴ particles/cm². Therefore, in contrast to solid state targets, single collision conditions are preserved. Available target gases are: H₂, He, N₂, Ar, Kr, Xe

Schematic drawing of the target apparatus: Inside the interaction chamber, the gas-jet is injected perpendicular to the ion beam. In order to keep the ESR base vacuum conditions (average: ~10^-11 mbar, interaction chamber: ~10^-9 mbar) stable, several differential pumping stages are installed to compensate the gas load.

Schematic draw of the typical experimental setup at the ESR gasjet target: X-ray detectors are detecting the emitted radiation under variouse angles with respect to the ion beam axis. Up- or down-charged ions are detected by particle detectors located behind the next dipole magnet. A coincidence technique is applied in order to discriminate the recorded X-rays with respect to the underlying radiative processes (e. g. REC, Bremsstrahlung).