Angular distribution measurement of gamma rays from inelastic neutron scattering on ⁵⁶Fe at the nELBE time-of-flight facility

¹ Helmholtz-Zentrum Dresden - Rossendorf, Postfach 510 119, 01314 Dresden, Germany
² Technische Universität Dresden, Postfach 100 920, 01076 Dresden, Germany

^a e-mail: m.dietz@hzdr.de; present address: School of Physics, Astronomy, University of Edinburgh, Edinburgh, UK
^b Present address: Czech Technical University in Prague, IEAP, Prague, Czech Republic
^c e-mail: a.junghans@hzdr.de
^d Present address: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
^e Present address: Institute for Nuclear Research (MTA ATOMKI), PO Box 51, 4001 Debrecen, Hungary

Published online: 13 September 2017

Abstract

Inelastic neutron scattering from ⁵⁶Fe was studied at the nELBE time-of-flight facility. The incoming neutron energy ranges from 100 keV to 10 MeV in the fast neutron spectrum, where high precision nuclear data are needed. A detector setup has been installed to investigate the γ-ray angular distributions. It contains five HPGe and five LaBr₃ detectors positioned at 30, 55, 90, 125 and 150 degrees relative to the beam axis. The intrinsic and the neutron induced background from the setup was subtracted by cyclical measurements with and without the natural Fe-target. Corrections for extended source efficiency and gamma-self-absorption, inside the target, were done using GEANT4 simulations. The angular distributions measured with the HPGe detectors are compared with earlier data. High neutron energy resolution up to a few keV was obtained with the LaBr₃ detectors due to their much better time resolution.