ELECTRIC DISSOCIATION OF NEGATIVE-IONS

As an alternative to naturally occurring negative ion discrimination, we consider the possibility of electric dissociation to discriminate between isobars, by destroying the weaker negative ion of a pair. The theoretical basis of negative ion dissociation using high electric gradients and an appropriate experimental setup are discussed. The possibility of negative ion destruction by electric dissociation during the first stage of tandem acceleration and at the ion source is also considered. In consequence, it is possible to place a limit on the electron affinity of some elements considering their survival in the AMS system. Mn-, Ca- and C-* among others are considered.