Activation method combined with characteristic X-ray counting: A possibility to measure image cross sections on heavy p-nuclei

For an improved modeling of the astrophysical nucleosynthesis of p-nuclei, low energy cross section data of alpha-induced reactions on heavy isotopes are needed. Technical difficulties hamper the experimental determination of these cross sections, therefore the relevant experimental data are almost completely missing. Here we present a new method for the cross section measurements, the activation technique based on the detection of characteristic X-ray radiation. The feasibility of the method is illustrated through the measurement of the 169Tmimage173Lu and 169Tmimage172Lu reaction cross sections. Despite the relatively long half-life of the reaction products (image and 6.7 days, respectively) it was possible to measure the cross section of the 169Tmimage173Lu reaction between image and 17.08 MeV. The 169Tmimage172Lu reaction cross section was derived from close above the threshold up to image. Details of the new method and the experimental results are presented.