Neutron capture cross section of 85Kr

Neutron capture and beta(-)-decay are competing branches of the s-process nucleosynthesis path at Kr-85, which makes it an important branching point. The knowledge of its neutron capture cross section is therefore an essential tool to constrain stellar models of nucleosynthesis. The goal is the measurement of the Kr-85(n,gamma) cross section via the time-of flight method. For this, several methods for the production of Kr-85 will be investigated. One of these is the irradiation of a Se-82 target with an alpha-beam. Here, the produced Kr-85 stays trapped inside the crystalline structure of the selenium. Due to technical difficulties and low yields, an alternative method is the use of reactor produced Kr-85. For future measurements of the neutron capture cross section of Kr-85 at FRANZ (Frankfurter Neutronenquelle am Stern-Gerlach-Zentrum), the goal is the use of a target with a high isotopic purity to reduce the background from Kr-83.