Kinematically complete experiments for double ionization of He atoms:
Development of a laser-pulsed photo-emission source

C.D. Schroeter, A. Dorn, R. Moshammer and J. Ullrich

Fakultaet fuer Physik, Universitaet Freiburg, D-79104 Freiburg, Germany

First kinematically complete experiments for the double ionization of He atoms by electron impact 
have been performed. For systematic investigation of this elementary process, the apparatus has 
been improved substantially. A three-stage supersonic He jet target has been built and a laser-pulsed 
photo-emission source is under construction. Both developments will result in a reduced data-taking 
time and improved electron and recoil-ion momentum resolution.