Nuclear non-proliferation via hardware and software work on the WATCHMAN detector

The WATer CHerenkov Monitor for Anti-Neutrinos (WATCHMAN) is a US/UK collaboration that aims to use nature's most 'ghostly' particle (the neutrino) for the extremely practical purpose of nuclear threat reduction. WATCHMAN will enhance the decades-old technology of water Cherenkov neutrino detectors with the emerging technique of gadolinium loading. Gadolinium has the highest cross-section for neutron capture of all the elements. When an anti-neutrino interacts in the detector via inverse beta decay, the coincidence of the produced positron and the capture of the leftover neutron provides an unambiguous signal.

This new gadolinium-tagging technique will be employed in other experiments for physics measurements. In WATCHMAN, the primary goal is nuclear threat reduction -- achieving a long-distance monitoring of nuclear reactor power and non-proliferation. Although the radiation from a nuclear weapons test can be shielded, the anti-neutrinos cannot be masked. Thus, a WATCHMAN-type can be an important tool for non-proliferation in the twenty-first century.

The Sheffield WATCHMAN group is working with the Boulby Underground Laboratory and the Atomic Weapons Establishment to design and construct a WATCHMAN prototype at the Boulby Lab. The construction phase began in October 2018, and our group is involved in nearly all areas of the experiment, including electronics, calibration, photomultiplier tubes, simulations, and data analysis. There is also the opportunity for a PhD student to get involved with R&D for future phases of WATCHMAN, such as new fast photosensors and novel detector targets. This R&D will aim to enhance the non-proliferation power of WATCHMAN whilst also opening up the detector to the possibility of studying particle and astroparticle physics topics, such as supernova neutrinos, CNO solar neutrinos, geoneutrinos, and neutrinoless double beta decay.