Development of neutron reflectometry for a HiCANS: The HERMES instrument at the JULIC Neutron Platform

High Current Compact Accelerator-driven Neutron Sources (HiCANS) have recently emerged as a possible solution to the drop in neutron provision in Europe due to the closure of several research reactors. Within this new trend, the Laboratoire Léon Brillouin (LLB) is currently assessing the performance of neutron techniques around this novel type of source. HERMES is a time-of-flight horizontal reflectometer that was operated by the LLB at the ORPHEE reactor until 2019 and was dedicated to soft matter studies. Through a collaboration with the Jülich Centre for Neutron Science, HERMES was installed in 2022 at the JULIC Neutron Platform (JNP) at the Forschungszentrum Jülich. This platform is able to deliver neutron pulses in the 100 μs - 2 s range and is very well suited to evaluate the feasibility of reflectivity experiments at a HiCANS. Since its installation and first tests in 2022, several improvements have been implemented at HERMES. Our current goal is to perform reflectivity experiments with large neutron mirrors as a proof of concept, as the flux at the JNP is several orders of magnitude lower than the original ORPHEE flux or the one expected at a HiCANS. Nevertheless, Monte Carlo simulations show that an instrument as HERMES operating at a HiCANS could match the performance of similar instruments at research reactors and spallation sources.