Neutron Detector R&D at ISIS: μRWELL Technologies for Future Scattering Instruments and Imaging Sys

Davide Raspino ISIS Neutron and Muon Source, Harwell Campus, Oxfordshire, OX11 0QX, UK

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Neutron scattering and imaging provide powerful tools for materials research, enabling studies of atomic and magnetic structure, dynamics, diffusion and engineering materials under in situ and operando conditions. Advances in neutron instrumentation place increasing demands on detector technologies, requiring higher spatial resolution, improved rate capability, greater reliability and scalable large-area systems. This presentation reviews neutron-detector activities at ISIS, focusing on micro-pattern gaseous detector (MPGD) technologies and R&D for future neutron-scattering instruments.

Several generations of 3He detector systems are currently deployed at ISIS. Resistive Wire Detectors (RWDs), used since the 1990s, continue to provide reliable large-area neutron detection and are undergoing modernisation of their readout electronics. Multi-Strip Gas Chambers (MSGCs), among the earliest MPGDs developed for neutron detection, also remain operational on selected instruments despite increasing challenges associated with component obsolescence.

A major area of current research is the μRWELL (micro-Resistive WELL), an MPGD technology combining high gas amplification with intrinsic spark protection through a resistive layer. This approach addresses limitations encountered with GEM-based detectors operating in high-pressure 3He/CF4 mixtures. Experimental studies have demonstrated stable operation, adequate gain for neutron detection and promising rate capability.

The μRWELL has been selected as the baseline detector technology for the proposed MUSHROOM indirect-geometry inelastic neutron spectrometer within the ISIS Endeavour Programme. Its large-area, high-rate detector system is intended to support measurements of lattice and molecular dynamics, magnetic excitations and other energy-dependent processes in materials. The presentation will describe the ongoing detector R&D, including μRWELL optimisation, high-pressure gas operation, readout-electronics integration and the transition from prototypes towards large-scale detector systems.

Recent developments of μRWELL detectors for neutron imaging will also be presented. These studies exploit the spatial resolution and scalability of MPGDs for applications including materials characterisation, non-destructive testing, engineering and cultural heritage.

Together, these activities demonstrate how continued innovation in gaseous neutron detectors can provide the performance required for the next generation of neutron-scattering and imaging instruments.