Modification of the DANFYSIK 911A ion source for production of negative ions

In the past few years ion-atom collision experiments involving negative ions have been carried out, namely electron spectra following the single- and double electron detachment from H- and He- ions have been measured. For such measurements negative ion beams with current in the nA range are needed. To produce negative ion beams in this range the DANFYSIK 911A positive ion source, which is connected to the beamline of the VdG-1 was replanned and modified. (K.A.)