ACC Area

Various physical and technology-dependent limits are encountered for key performance parameters of accelerators such as high-gradient acceleration, high-field bending, beam size, beam brightness, beam intensity and luminosity. This paper will review these limits and the associated challenges. [...]

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+. [...]

The LIBELLE experiment performed at the experimental storage ring at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany, has successfully determined the ground state hyperfine (HFS) splittings in hydrogen-like (${}^{209}{\mathrm{Bi}}^{82+}$) and lithium-like (${}^{209}{\mathrm{Bi}}^{80+}$) bismuth. The study of HFS transitions in highly charged ions enables precision tests of QED in extreme electric and magnetic fields otherwise not attainable in laboratory experiments. [...]

The FAIR project is aiming at providing high-energy beams of ions of all elements from hydrogen to uranium, antiprotons and rare isotopes with high intensities. The existing accelerator facility of GSI and the future FAIR facility employ a variety of circular accelerators like heavy ion synchrotrons (SIS18 and SIS100) and storage rings (ESR, CRYRING, CR and HESR) for the preparation of secondary beams and experiments. [...]

Activation of high-intensity heavy-ion accelerators due to beam losses is a serious issue for accelerator parts like collimators, magnets, beam-lines, fragment separator components, etc. The quantification of the induced activity and the prediction of the radiation levels in an accelerator and its environment may have a positive impact on the decreasing of radiation hazards during “hands on” maintenance as well as on the optimisation of the machine operation. [...]

A sc cw-linac with variable output energy from 3.7 to 7.5 MeV/u for ions with mass to charge ratio of A/Z<6 is recently under development at HIM and GSI. Following the results of the latest RF-tests with the newly constructed sc CH-DTL cavity, even heavier ions up to Uranium 28+ could be potentially accelerated with the already reached higher RF-voltage. [...]