OPERATION OF THE NEW MICROPROBE AT BOCHUM

The successful operation of a nuclear microprobe system using a superconducting solenoid as final lens is described. This system allows a minimum focal length of 7.5 cm for 3 MeV protons resulting in a demagnification factor of 80 at 610 cm object distance while image aberration effects are very small. Combined with a precise computer controllable slit system high precision STIM measurements are possible. As a new feature in microprobe technology the final lens can be used to focus backscattered ions, thus significantly increasing the effective detector solid angle relative to conventional RES techniques. This leads to a higher sensitivity for RES analysis at low beam currents.