Invited Speakers

Overview of UK Nuclear Physics MPGD Activities (TPC-focused)

Jack Bishop

Nuclear physics over the past fifteen years has made increasingly heavy use of Time Projection Chambers (TPCs) to facilitate a new regime of study. TPCs operating in active-target mode, where the gas is both the target and the readout medium, allow for a much thicker target (and hence higher statistics) without loss of energy resolution. This makes them ideally suited for high-impact measurements involving Radioactive Ion Beams (RIBs) where the limiting factor is the low beam intensities achievable at most modern facilities.

This talk will highlight some devices/collaborations that have strong UK involvement: including TexAT/TeBAT, and TACTIC. Both devices have different fundamental technologies and science goals, but share similar challenges which will be presented, along with possible future avenues for research and links between disciplines.

Recent Developments in Micro Pattern Gaseous Detector at the MPT Workshop at CERN

Adam Drozd

This talk will present the Micro Pattern Technologies (MPT) workshop, its team, infrastructure and capabilities, with an emphasis on recent developments in Micro Pattern Gaseous Detector (MPGD) technologies. The main part of the presentation will focus on MPGD fabrication techniques, covering GEM, MicroMegas and their different implementations, as well as uRWELL and uRGrooves. Recent developments aimed at improving detector performance and rate capability will also be discussed.The talk will then present developments in the workshop’s magnetron sputtering machine for the deposition of Diamond-Like Carbon (DLC) layers, focusing on the precision and uniformity of their resistive properties and their application to MPGDs. Finally, recent developments in aluminium circuits, including rigid, flexible, double- and multilayer structures, superconducting circuits, and the deposition of different materials as converter layers for PICOSEC detectors, will be presented.

A hybrid-mode active target spectrometer for nuclear reactions with radioactive ion beams

Liam Gaffney

Nuclear reactions with radioactive ion beams are used to study the structure of nuclei away from the line of stability. They have been used to reveal the disappearance of the traditional magic numbers as nuclear shell structure evolves towards the so-called island of inversion, shine a light on nucleosynthesis in astrophysical environments and probe the origin of exotic nuclear shape phenomena. Such direct reaction experiments remain extremely challenging and limited in the achievable energy resolution and luminosity, often with compromises necessary to both to make an experiment viable. One limiting factor is the use of solid targets for hydrogen- and helium- like species (p, d, t, h, α) as part

of a molecular compound or within a solid matrix, necessarily containing other species (carbon, silicon, titanium) that produce a nuclear reaction background. Energy losses in the target material further limit the achievable thickness, and thus the luminosity, when trying to maintain acceptable energy resolution.

A major improvement has been made in the last two decades in spectrometer design, utilising a large bore solenoidal magnet coupled with a position-sensitive silicon detector along the reaction axis, to overcome intrinsic limitations in performing these reactions with radioactive ion beams. Three such solenoidal spectrometers now exist worldwide: HELIOS at Argonne National Laboratory, the ISOLDE Solenoidal Spectrometer in CERN and SOLARIS at the Facility for Radioactive Ion Beams (FRIB). The technique was expanded with the use of the active target time projection chamber (AT-TPC) in the US and the SpecMAT active target in Europe.

This presentation will propose the use of a new hybrid-mode spectrometer, combining the high luminosity, low background environment of an active target, with the superior energy and position resolution that can be achieved with position-sensitive silicon detectors. It is proposed to use a Micropattern Gaseous Detector (MPGD) to provide the reaction vertex, though there are still some challenges to be worked out with help from the experts in the community.

Gaseous Detectors in Direct Dark Matter Searches

Patrick Knight

Dark matter is known to make up more than 80% of the matter in the universe, however, its particle nature remains a mystery. Gaseous detectors play a key role in the search for dark matter, from being used in direct detection experiments to measuring rare atomic effects to enhance existing and future experiments. Several detector technologies will be presented, including time projection chambers, optical time projection chambers, and spherical proportional counters, and how these are employed in the direct dark matter detection effort. The talk will touch upon the varied applications, covering directional detection, low-mass particle dark matter searchers, and the Migdal effect.

Eshita Kumar

MICRO MEsh GAseous Structure (Micromegas) detectors are micro-patterngaseous detectors with excellent spatial resolution due to their small scale readoutpitch and high rate capability due to small amplification gaps and the fastevacuation of positive ions. However, large-scale detectors with pixel-readoutneed thousands of readout channels, which leads to increased cost, power consumption,and significant heat generation, often requiring dedicated coolingsystems.This talk explores a way to reduce the number of readout channels by ordersof magnitude without compromising position accuracy by the use of chargesharingpixel anodes coupled to a strip readout with up to 4-fold strip information.Three layers of pixels are stacked, where the pixel layer next to theresistive DLC anode has a typical pitch of 0.4 mm x 0.4 mm and the successivelayers have a factor of 2 larger structures. The readout pixels are lithographicallysegmented into substructures that are coupled to the readout electronicsusing galvanic vias and copper readout lines. The position information usingthe charge distribution created by a muon traversing the detector is containedin the readout pixels through capacitive coupling within the layers.Two prototypes of this detector were tested at CERN’s SPS beam of 120GeV muons and pions. The results of the performance and efficiency of thesedetectors will be presented. Comparison with the simulation results using themethod of weighting fields with the help of ANSYS and Garfield++ will alsobe discussed.

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

Davide Raspino

Neutron scattering facilities worldwide are expanding through the construction of new high-brightness sources and the upgrade of existing instruments. These developments place increasing demands on detector technologies, requiring higher spatial resolution, improved rate capability, greater reliability, and sustainable long-term operation. This presentation reviews neutron-detector activities at the ISIS Neutron and Muon Source, focusing on 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 currently undergoing modernisation of their readout electronics. Multi-Strip Gas Chambers (MSGCs), the very first MPGDs, originally developed at the Institute Laue-Langevin, also remain operational on selected instruments despite increasing challenges posed by component obsolescence.

A major area of current research is the μRWELL (micro-Resistive WELL) detector, a micro-pattern gaseous technology that combines high gas gain with intrinsic spark protection through a resistive layer. This approach addresses limitations encountered in GEM-based detectors operating in high-pressure 3 He/CF 4 mixtures. Experimental studies have demonstrated stable operation, adequate gain for neutron detection, and good rate performance, making μRWELL well suited to demanding neutron scattering applications. The μRWELL has been selected as the baseline detector technology for the proposed MUSHROOM spectrometer within the ISIS Endeavour Programme. MUSHROOM is a next-generation indirect-geometry inelastic neutron spectrometer designed to deliver substantial gains in measurement capability through a large-area, high-rate detector system. The presentation will describe the ongoing R&D programme supporting this development, including detector optimisation, operation in high-pressure gas mixtures, electronics integration, and large-scale system implementation. In addition, recent studies of uRWELL detectors for neutron imaging will be presented. These developments aim to exploit the excellent spatial resolution and scalability of micro-pattern gaseous detectors for imaging applications ranging from cultural heritage and archaeometry to more general neutron imaging and non-destructive testing. Together, these activities highlight the continuing role of gaseous detector innovation in enabling future neutron scattering and imaging facilities.