A NOVEL HIGH PRECISION SLIT SYSTEM

Abstract A new high precision slit system has been developed for the nano beam facility SNAKE (Supraleitendes Nanoskop fur Angewandte Kernphysikalische Experimente) which is under construction at the Munich tandem accelerator. Cylindrically strained germanium wafers with a bending radius of 50 mm are used as optimized slit edges. High resolution and angle resolved energy distributions of the transmitted protons were measured by means of a Q3D magnetic spectrograph at incident energies of 20 MeV. The measurements revealed the expected strong correlation between small angle scattering and energy loss processes at the slits. Within SNAKE's angular acceptance the ratio of particles suffering energy loss by interacting with the slit and particles not interacting with the slit is less than 0.6% even for aperture widths of 2 μm.