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%0 Thesis
%A Rimmler, Marius
%T Development of a multiplexer system and measurement of the neutron yield for a low-energy accelerator-driven neutron source
%I RWTH Aachen University
%V Dissertation
%C Aachen
%M RWTH-2021-11262
%P 1 Online-Ressource : Illustrationen, Diagramme
%D 2021
%Z Veröffentlicht auf dem Publikationsserver der RWTH Aachen University 2022
%Z Dissertation, RWTH Aachen University, 2021
%X The High-Brilliance neutron Source (HBS) project aims at developing a low-energy accelerator-driven neutron source facility providing neutron beam brilliances at the corresponding instruments, which are very competitive to medium-flux fission-based research reactors. To obtain a large beam brilliance at HBS, the full-fledged facility simultaneously operates different neutron instruments, which subdivide into three target stations, each efficiently operated to supply different neutron pulse structures. This will be realized by generating an interlaced proton pulse structure containing three different proton beam timing schemes, which are then distributed to the individual target stations. The distribution of the different proton pulse sequences to the target stations is performed by a proton beam multiplexer system which is developed in the frame of this thesis. A test setup of this multiplexer system, which primarily consists of a kicker and a septum magnet, is developed at the 45 MeV proton accelerator facility JULIC of Forschungszentrum Jülich GmbH. Here, the main focus is on the development of a new type of permanent-magnet-based septum magnet featuring three different magnetic dipole field regions in close proximity. The design process of such a septum magnet is presented in detail together with the analysis of a prototype based on the corresponding magnet technology. Furthermore, proton pulse distribution is demonstrated with the operation of the kicker magnet of the multiplexer test setup being synchronized to the proton beam chopper of JULIC. The integration of the multiplexer system at HBS is described thoroughly including the design of a septum magnet based on the developments at JULIC and scaled to serve the larger proton beam energy of 70 MeV. In the context of the HBS multiplexer system, the HBS High-Energy Beam Transport (HEBT) beamline is designed and associated beam-dynamics calculations are carried out. The effect of the field quality of the HBS septum magnet on the transmission through the HEBT is investigated by particle tracking studies. In addition, another contribution to the maximization of the neutron beam brilliance at HBS is made by measurements of the neutron yield for different target materials applicable at low-energy accelerator-driven neutron sources in the proton energy range of 22-42 MeV. The measurement technique is based on the analysis of the 2.2 MeV prompt gamma line induced by thermal neutron capture in the hydrogen nuclei of a polyethylene moderator. The experimental results are used to benchmark the results obtained from numerical simulations and extrapolated to 70 MeV, which helps selecting the appropriate target material at HBS providing the largest proton-energy-dependent neutron yield and thus neutron beam brilliance.
%F PUB:(DE-HGF)11
%9 Dissertation / PhD Thesis
%R 10.18154/RWTH-2021-11262
%U https://publications.rwth-aachen.de/record/836357