Determining reaction cross sections via characteristic X-ray detection : alpha-induced reactions on Tm-169 for the astrophysical gamma-process

The cross sections of the Tm-169(alpha, gamma)Lu-173 and Tm-169(alpha,n)Lu-172 reactions have been measured first time using a new method, by detecting the characteristic X-ray radiation following the electron capture-decay of Lu-172,Lu-173. Despite the relatively long half-life of the reaction products (T-1/2 = 500 and 6.7 days, respectively) it was possible to measure the cross section of the Tm-169(alpha, gamma)Lu-173 reaction close to the Gamow window (T-9 = 3.5 GK), between E-c.m. = 13.16 and 17.08 MeV. The Tm-169(alpha,n)Lu-172 reaction cross section was measured from E-c.m. = 11.21 MeV up to E-c.m. =17.08 MeV. The experimental results have been compared to theoretical predictions. (C) 2010 Elsevier B.V. All rights reserved.