Abstract
The discovery of naturally occurring long-lived isomeric states ( yr) in the neutron-deficient isotopes [A. Marinov et al., Phys. Rev. C 76, 021303(R) (2007)] was reexamined using accelerator mass spectrometry (AMS). Because AMS does not suffer from molecular isobaric background in the detection system, it is an extremely sensitive technique. Despite our up to two orders of magnitude higher sensitivity we cannot confirm the discoveries of neutron-deficient thorium isotopes and provide upper limits for their abundances.
- Received 11 November 2008
DOI:https://doi.org/10.1103/PhysRevC.78.064313
©2008 American Physical Society