acta de conferencia
"L-X-ray production cross-sections for PXAMS: Target and energy dependence for 50-200 MeV hafnium ions"
S. Winkler, L.K. Fifield, S.G. Tims and J. Fernández-Niello
Proc. of the "10th International Conference on Accelerator Mass Spectrometry", Berkeley, California, USA, September 5-10, 2005. Ed. J. Knezovich, T. Brown, B. Buchholz, R. Finkel, T. Guilderson, M. Kashgarian, G. Nimz, T. Ognibene, S. Tumey and J. Vogel
Nucl. Instrum. Meth. B 259(1) (2007) 260-264
Abstract
In order to detect the long-lived radioisotope 182Hf (t1/2 = 8.9 Ma), a potential supernova isotope signature, we investigated PXAMS as a method of isobar separation for Hf and W. One of the problems of the method is low efficiency. Since there are no reliable quantitative predictions on cross-sections leading to the emission of X-rays from collisions involving fast Hf ions, we determined the energy dependent cross-sections for a number of target elements. A PXAMS system of maximum efficiency was then constructed on the basis of the data obtained. The efficiency of the final setup, defined as the ratio of the number of X-rays detected to the number of incident Hf ions, is 1.2%. The overall efficiency, including negative-ion formation probability and transmission through the accelerator, is 1 × 10-6.
DIVISION FISICA DE IONES PESADOS Y AMS
