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

Abstract

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.

Beam Dynamics Studies for the Target Beamlines of the High Brilliance Neutron Source

“…The integration of the multiplexer system at HBS including the design of a septum magnet is based on dedicated developments using a 45 MeV proton beam from the JULIC cyclotron at Forschungszentrum Jülich and scaled for the larger proton beam energy of 70 MeV at the HBS. In connection with the HBS multiplexer system, the HBS High Energy Beam Transport (HEBT) beamline was designed and the associated beam dynamics calculations were carried out [4,5].…”

“…The geometric acceptance of the beamline can be estimated from the calculated Beta functions and dispersions along the beamline [4,5] . The aperture of the magnets is planned to be 60 mm.…”

“…The actual 6σ beam has an elliptical shape with an extent of 24 mm in the vertical plane and 8 mm in the horizontal plane. The effect of the field quality of the TFSM on the transmission through the HEBT has also been investigated in detail by particle tracking studies [4,5]. The simulated beam transmission through all three field regions is close to 100 %.…”

The High Brilliance neutron Source (HBS): A project for a next generation neutron research facility

“…Table 1. Key parameters of the HBS Accelerator [5] protons of energy 70 MeV, up to 100 mA peak current, beam duty factor of 6%, average proton beam power of 420 kW High Energy Beam Transport (HEBT) [6] multiplexer (kicker & septum magnet) distributing the beam to three TMR stations Target [7] Ta target with microchannel water cooling; 10x10 cm 2 active area; designed for 100 kW power TMR stations [8] TMR 2 : 24 Hz (667 µs p-pulse)) TMR 1 & 3 : 96 Hz (167 µs p-pulse) each TMR offers 12 beam ports Moderators [9,10] thermal moderator: light water cold moderators: 1d «finger» moderators (solid mesitylene, solid methane, liquid para-hydrogen)…”

“…All critical components of HBS have been separately tested: (i) the accelerator is largely based on the MYRRHA (https://www.myrrha.be) design, (ii) cross sections for neutron release from different materials have been measured in absolute units [14], (iii) a prototype of the multiplexer has been realized and tested [6], (iv) the target has been tested up to the design value of 1 𝑘𝑊/𝑐𝑚 $ at an electron beam facility, (v) "finger" moderators for all moderator materials under consideration were built and tested. However, in order to verify the interplay of all components, to improve the design and perform method development, a test station has been realized on the premises of the Nuclear Physics Institute of Forschungszentrum Jülich.…”