Redesign of the Goeteborg negative-ion-beam-apparatus towards a test facility for laser photodetachment applications in AMS

Negative ions are utilized in Accelerator Mass Spectrometry (AMS) on the low energy side of the tandem accelerator. A unique approach to further improve isobaric selectivity of AMS is to exploit the differences in the electron affinities of individual isobars by laser photodetachment. Laser radiation with energy above the photodetachment threshold of the unwanted isobar suppresses this species by selective neutralization, while leaving the wanted higher threshold isobar unaffected. This technique, called Laser Photodetachment Mass Spectrometry (LPMS), is presently refined at Goeteborg University. For preparatory studies and subsequent employment on heavy molecules of interest, the ion beam apparatus was considerably optimized by a corresponding redesign. Using ion optical simulations, the transmission through the apparatus could be enhanced, while in parallel a higher mass resolution could be realized. These activities serve as preparatory steps towards separation of the interesting ultra trace isotope 182Hf from the disturbing isobar 182W using LPMS