Proton Beam Multiplexer Developments for Multi-Target Operation at the High-Brilliance Neutron Source HBS

The High Brilliance Source (HBS) project aims to develop a scalable Com-pact Accelerator-driven Neutron Source (CANS) enabling neutron fluxes at thecorresponding instruments comparable to medium-flux fission-based research re-actors. The full-fledged HBS facility features simultaneous operation of differentneutron instruments which subdivide into three target stations each efficientlyoperated to supply different neutron energies. This will be realized by differ-ent proton beam timing schemes distributed to the target stations in order toobtain the optimal balance between wavelength bandwidth and resolution ofthe time-resolved neutron spectrum extracted from the thermal or cold neu-tron moderator according to the requirement of the experiment. For this reasona proton pulse distribution device, i.e. multiplexer, has to be developed thatallows the spatial separation of two different subsequent proton pulses withinless than 800 μs. This contribution presents concepts on the realization of amultiplexer for a 70 MeV, 100 mA proton beam with 384 Hz, 96 Hz, 24 Hz pulsesequences and 2 % duty cycle as well as developments on a multiplexer devicerealized at 45 MeV proton energy, μA peak currents and an identical timingscheme

Proton beam multiplexer developments towards HBS

The High Brilliance neutron Source (HBS) project aims to develop a scalableCompact Accelerator-driven Neutron Source (CANS) enabling neutron fluxesat the corresponding instruments comparable to medium-flux fission-based re-search reactors. The full-fledged HBS facility features simultaneous operationof different neutron instruments which subdivide into three target stations eachefficiently operated to supply different neutron energies. This will be realized bydifferent proton beam timing schemes distributed to the target stations in orderto obtain the optimal balance between wavelength bandwidth and resolution ofthe time-resolved neutron spectrum extracted from the thermal or cold neutronmoderator according to the requirement of the experiment. For this reason aproton pulse distribution device, i.e. multiplexer, has to be developed. Thispresentation includes developments of a multiplexer test setup at the 45 MeVCOSY injector JULIC in Juelich as well as concepts towards an implementationof such device into the final 70 MeV HBS framework

Proton Beam Multiplexer Developments for Multi-Target Operation at the High-Brilliance Neutron Source HBS

The High-Brilliance neutron Source project (HBS) aims at developing a medium-flux acceleratordriven neutron source based on a 70 MeV, 100mA proton accelerator. The concept intends to optimize the facility such that it provides high-brilliance neutron beams for instruments operating at di_erent time structures. This can be realized by three di_erent target stations irradiated with di_erent proton pulse sequences. The appropriate proton pulses will be distributed by a Multiplexer unit. In the following, we present the integration of this Multiplexer with the HBS beam optics as well as ongoing developments of this unit and several components of the Multiplexer at the COSY facility in Jülich

Development of a Multiplexer System and Measurement of the Neutron Yield for a Low-Energy Accelerator-Driven Neutron Source

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 45MeV proton accelerator facility JULIC of Forschungszentrum Jülich GmbH. Here, the main focus is on the development of a newtype of permanent-magnet-based septum magnet featuring three different magnetic dipole field regions in close proximity. The design process of such a septum magnet ispresented in detail together with the analysis of a prototype based on the correspondingmagnet 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 70MeV. 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 22MeV to 42MeV. The measurement technique is based on the analysis of the 2.2MeV 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 70MeV, which helps selecting the appropriate target material at HBS providing the largest proton-energy-dependent neutron yield and thus neutron beam brilliance

Recent Extensions of JULIC for HBS Investigations

At the Forschungszentrum Jülich (FZJ) the energy variable cyclotron JULIC is used as injector of the Cooler Synchrotron (COSY) and for low to medium current irradiations of different types. Recently a new target station was set up and is mainly used for tests of new target materials, neutron target development and neutron yield investigations with high power proton or deuteron beam in perspective of a high brilliance accelerator based neutron source (HBS) with the Jülich Center for Neutron Science. The neutrons are produced exposing material targets or compounds to proton or deuterium particles of relative low final particle energy in the MeV range and will be optimized for neutron scattering to be realized at reasonable costs. Beside this, ToF-experiments are performed to investigate and optimize the pulsing structure for HBS. The target station is installed inside an experimental area offering space for complex detector and component setups for nuclear and neutron related experiments. But it is used for other purposes like electronic or detector tests and irradiation as well. This report briefly summarizes the history of JULIC and the activities for its future perspectives

Recent Extensions of JULIC for HBS Investigations

At the Forschungszentrum Jülich (FZJ) the energy variable cyclotron JULICis used as injector of the Cooler Synchrotron (COSY) and for low tomedium current irradiations of different types. Recently a new target sta-tion was set up and is mainly used for tests of new target materials, neutrontarget development and neutron yield investigations with high power pro-ton or deuteron beam in perspective of a high brilliance accelerator basedneutron source (HBS) with the Jülich Center for Neutron Science. The neu-trons are produced exposing material targets or compounds to proton ordeuterium particles of relative low final particle energy in the MeV rangeand will be optimized for neutron scattering to be realized at reasonablecosts. Beside this, ToF-experiments are performed to investigate and op-timize the pulsing structure for HBS. The target station is installed insidean experimental area offering space for complex detector and componentsetups for nuclear and neutron related experiments. But it is used for otherpurposes like electronic or detector tests and irradiation as well. This re-port briefly summarizes the history of JULIC and the activities for its futureperspectives

Developments of a multiplexer system for the High-Brilliance Neutron Source HBS

The High-Brilliance Neutron Source project (HBS) aims at developing a medium-flux accelerator-driven neutron source based on a 70 MeV, 100 mA proton accelerator. The concept optimizes the facility such that it provides high-brilliance neutron beams for instruments operating at different time structures. This can be realized by generating an interlaced proton pulse structure, which is unraveled and sent to three different target stations by a multiplexer system. In the following we present the developments of a multiplexer system at the JULIC accelerator at Forschungszentrum Jülich GmbH (FZJ), which serves as test facility for HBS. The main components of the JULIC multiplexer system are designed to be scalable to the HBS parameters

Monte Carlo simulation of neutron yield measurements for Be, V and Ta targets

The High Brilliance Neutron Source (HBS) project was initiated at the Jülich Centre for Neutron Science of the Forschungszentrum Jülich (JCNS). It aims to develop a medium neutron source facility based on a linear accelerator, scalable up to 70 MeV proton energy and optimized to deliver high brilliance neutron beams to a variety of neutron instruments. To better understand the neutron yield of different materials at different energies of bombarding protons, measurements to determine the proton-induced neutron production were carried out at the accelerator facility Julic-Cyclotron at Forschungszentrum Jülich. The experiment was set up with different targets (e.g. beryllium, vanadium and tantalum), which were surrounded by a polyethylene moderator. The neutron yield was indirectly determined by measuring the gamma radiation induced by thermal neutron capture in the moderator. The calibration was performed with an Am-Be neutron source to obtain the neutron gamma conversion rate. Corrections were made for escaping neutrons with the parameter of neutron escape ratio, which was calculated from Monte Carlo simulations. The details of the simulations will be introduced at the workshop. The total neutron production compared with measurements, the neutron and gamma escape ratio and the spectrum as well as the neutron flux distribution will also be presented