Heidelberg 2015 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 11: Nuclear Astrophysics 1

HK 11.1: Gruppenbericht

Montag, 23. März 2015, 17:00–17:30, K/HS2

Investigation of proton- and α-capture reactions for the
astrophysical γ process via in-beam γ-ray spectroscopy — •Lars Netterdon¹, A. Endres², J. Mayer¹, P. Scholz¹, and A. Zilges¹ — ¹Institute for Nuclear Physics, University of Cologne — ²Institute for Applied Physics, Goethe University Frankfurt am Main

The p nuclei, about 30 to 35 neutron-deficient stable nuclei, are bypassed by the s and r process. It is believed, that the majority of these nuclei is produced via photodisintegration reactions and subsequent β decays during the γ process. Reaction rates for the γ-process reaction network are to a large extent calculated within the scope of the Hauser-Feshbach statistical model. The nuclear-physics input, such as optical-model potentials and γ-ray strength functions, must be constrained experimentally in order to reduce the uncertainties of reaction-rate calculations. A dedicated setup for in-beam nuclear astrophysics experiments aiming at the aforementioned input parameters using the γ-ray spectrometer HORUS will be introduced [1]. The ¹¹²Sn(α,γ)¹¹⁶Te reaction will be presented, being the first successful in-beam α-capture experiment on a heavy nucleus to date. In addition, an experiment on the ⁸⁹Y(p,γ)⁹⁰Zr reaction is presented, where special emphasis is put on the partial cross-sections. With the aid of partial cross-sections, a method is shown which allows an experimental constraint on the γ-ray strength function in the compound nucleus ⁹⁰Zr. Supported by the ULDETIS project within the UoC Excellence Initiative institutional strategy.

[1] L. Netterdon et al., Nucl. Instr. Meth. A 754 (2014) 94