Bonn 2010 – wissenschaftliches Programm
HK 53.2: Vortrag
Donnerstag, 18. März 2010, 17:00–17:15, HG IV
A new detector system for low energy neutrons for R3B — •Christoph Langer — Institut für Kernphysik, Universität Frankfurt, D-60438 Frankfurt am Main, Germany — GSI Darmstadt, Planckstrasse 1, 64291 Darmstadt, Germany
A new neutron detector, consisting of plastic scintillation material and based on the proton-recoil detection, for low energy neutrons in the region of several hundreds of keV up to a few MeV will be
presented. The detector array will be placed close to the R3B target at a distance of 1m in the upcoming FAIR facility in Darmstadt for detailed studies of (p,n)-reactions, which lead to a better understanding of astrophysically interesting β-decay lifetimes, GT-strengths and isovector giant resonances in exotic nuclei. The detector is used for time-of-flight measurements between the reaction
point in the target and the detector array. The time resolution is required to be less than 1ns with a good angular resolution.
Tests with different γ-sources and a 252Cf source were performed at ATOMKI in Debrecen, Hungary. Neutron detection efficiency studies were carried out with a neutron beam at the Los Alamos Neutron Scattering Center, LANSCE, in New Mexico, USA. We used a double time-of-flight technique to determine the efficiency for neutron-induced fission neutrons from 235U. The 235U was installed in a fission chamber at FP5 viewing a lower tier moderator at a distance of 9m. First results of these measurements will be presented and discussed. This project is supported by the HGF Young Investigators Project VH-NG-327.