OPERATION OF THE NEW MICROPROBE AT BOCHUM

The successful operation of a nuclear microprobe system using a superc onducting solenoid as final lens is described. This system allows a mi nimum focal length of 7.5 cm for 3 MeV protons resulting in a demagnif ication 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 fe ature in microprobe technology the final lens can be used to focus bac kscattered ions, thus significantly increasing the effective detector solid angle relative to conventional RES techniques. This leads to a h igher sensitivity for RES analysis at low beam currents.