Adrian D. Hillier

Compact scintillation detectors with simultaneous gamma and neutron sensitivity are increasingly relevant for mixed-field monitoring and nuclear measurements under size and cost constraints. This work characterizes a compact Cs₂LiLaBr₆:Ce (CLLB:Ce) detector with integrated SiPM readout at the ISIS Muon Facility. We assess its performance as a mixed-field monitor and a complementary tool for preliminary measurements in muon-based cultural heritage applications, where reference HPGe detectors are limited by size or geometry. The detector response was investigated under three conditions: environmental background at the muon facility, revealing intrinsic alpha activity in the 3–5 MeV region; simultaneous irradiation with an AmBe neutron source and a ¹³⁷Cs gamma source, producing an enhancement in the 3.1–3.5 MeV region arising from both gamma-like and charged-particle-like contributions; PSD-resolved analysis identified a localized charged-particle-like excess near 3.2–3.3 MeV compatible with a neutron-sensitive response, including a possible contribution from ⁶Li(n,α)³H capture; and a proof-of-concept measurement on an irradiated Ag-Cu alloy plate. Pulse-shape discrimination based on digital charge integration yielded figures of merit of 1.71 ± 0.03 for background data and 1.53 ± 0.03 for the AmBe + ¹³⁷Cs configuration. Finally, the Ag-Cu alloy measurement demonstrated the feasibility of operating the detector during muon irradiation to record spectral features compatible with Ag- and Cu-related emissions. While quantitative archaeometric applications require further calibration and benchmarking against HPGe, these results support the feasibility of using compact CLLB:Ce detectors as complementary mixed-field monitoring tools at muon facilities.

The specific depth‐profiling capabilities of the muonic x‐ray emission spectroscopy (μ‐XES) technique have proved to be effective for examination of the elemental distribution within ancient coins. This ‘layered’ analysis can also be applied to the examination of ancient faience, the production of which can result in distinct layers (glaze, interaction, and body). Initial results also indicated the presence of nitrogen and carbon, something with potential implications for production techniques of these objects. Moreover, by using this method, the samples do not become radioactive. This paper presents a pilot study of this method used on three faience samples, two from the Nubian (ancient Sudanese) site of Meroe (c.350 bce –350 ce ) and one from the ancient Egyptian site of Beni Hasan (c.2055–1650 bce ).

Quasi-one-dimensional (quasi-1D) materials provide a compelling platform where reduced dimensionality stabilizes intertwined topological and superconducting phases. Here we report superconductivity in a new Bi-based quasi-1D compound, PtPb ₃ Bi, which hosts a nontrivial electronic structure. It exhibits type-II superconductivity below 3.01(1) K. Heat capacity and transverse-field muon spin rotation/relaxation (μSR) measurements demonstrate a fully gapped isotropic s-wave state with moderate electron-phonon coupling, while zero-field μSR confirms the preservation of time-reversal symmetry (TRS). Transport measurements reveal low carrier mobility with diffusive normal-state transport. Electronic structure calculations show strong dispersion along the quasi-1D direction and relatively flatter bands in the transverse plane, giving rise to pronounced Fermi surface nesting in the k _x –k _y plane. Consistent with this, the compound undergoes a charge-density-wave transition at 280(1) K. The flow of Wannier charge centers, together with surface-state dispersion, establishes nontrivial band topology. These results identify PtPb ₃ Bi as a new quasi-1D superconductor with nontrivial electronic structure and a promising candidate for topological superconductivity.

The science programme using muons for elemental analysis is rapidly expanding across a wide range of science areas, from cultural heritage to energy materials to advanced manufacturing. Most muon facilities have, or are developing, new instrumentation to answer relevant science questions, which subsequently requires the development of a dedicated software package. EVA (Elemental Visualisation and Analysis) has been developed for modelling, optimising experimental setups and analysing data. EVA is available for Windows, Linux and macOS and is fully open-access via GitHub. EVA should be able to directly read in data files produced by muon data acquisition systems and be used to analyse data during data collection and offline analysis, and can be used at both continuous and pulsed muon sources.

Almost 40 years have now passed since the first instrument was commissioned at the ISIS pulsed muon source. In this time, the facility has grown significantly, with six scheduled instruments producing a wide range of science across a broad range of subject areas. This paper takes a forward look at how we see the facility evolving in the coming years. Upgrades are in progress to develop a state-of-the-art μ SR spectrometer (Super-MuSR) using a novel event-based data acquisition system (Digital Muons). A future project is envisaged to upgrade EMU (nuEMU), exploiting many of the technologies we are currently developing for Super-MuSR. The recent transition of the RIKEN-RAL beamlines to ISIS in 2021 triggered a major upgrade that will be completed with the installation of a new decay solenoid in 2027. Equipped for future running, a new instrument suite is being considered that can best exploit the capabilities of these beamlines. Prototype elemental analysis (MuX) and chip irradiation (MEIS) instruments are now in operation with a growing user community, with plans now well-advanced for a major development in this area. A new instrument for μ ^± SR is also planned (CHIMERA), combining the capabilities of existing spectrometers and optimised for experiments exploiting the unique beam properties of RIKEN-RAL. Recent improvements to the present source are considered, together with the exciting opportunities that will come with the development of ISIS-II, the next-generation source/facility, in the 2040s.

The single-bit and multiple-cell upset cross sections for positive and negative muons and 14-MeV neutrons of a commercial 40-nm CMOS SRAM have been experimentally determined in static and dynamic modes. In the case of the muons, the momentum with the highest cross section was predicted by EVA, a custom simulation tool, in spite of not having the characteristics of the chemicals used to build the device and the printed circuit boards. Positive muons only cause single-bit upsets, while negative muons and neutrons also induce multiple cell upsets of various multiplicities. The number of multiple events was determined by using LELAPE, a tool that explores the statistical properties of the set of data. In all the tests, the static cross-section was on the same order as the dynamic one, or even higher. Besides, in the case of muons, the cross section is not negligible at standard power supply voltages. These phenomena are attributed to a side effect of the internal circuitry added by the manufacturer to adapt the bias voltage and to minimize the power consumption.