R&D on Liquid Argon detectors for neutrino physics

The historical discovery of the Higgs boson, a long-sought particle, has made waves around the world, but another particle, the neutrino, has also attracted a lot of attention recently. This elusive particle of the Standard Model of Particle Physics (this same model that predicted the existence of the Higgs) has already surprised physicists in the past. The seminal discovery that neutrinos have mass (although tiny) has seriously challenged the Standard Model, which predicted massless neutrinos. In the last years, amazing findings have once more brought neutrinos to the forefront of Science.

Although neutrinos are one of the most abundant particles in the Universe, they are probably the least understood because they interact very weakly with matter. For this reason, very large detectors are required to answer the remaining questions neutrino physics can address, like explaining why matter won over the anti-matter in the Universe (one of the greatest puzzle of Science).

Liquid Argon (LAr) detectors are a promising new technology to study neutrinos. These state-of-the-art detectors are extremely efficient at detecting neutrinos and allow 3D images of the particle interactions, which provide unprecedented ways to reject undesirable interactions.

The UK has recently undertaken a scientific programme to develop and better understand this technology. This proposal offers a unique opportunity to fulfil the goals of the new strategy by increasing significantly the UK involvement in the MicroBooNE experiment, the only LAr neutrino experiment that will be running in the next years.

The group formed from this proposal, while making significant scientific impact with the MicroBooNE results, will also build small LAr detectors that will be used for R&D. With these new cutting-edge test stands, the Oxford group will be able to perform much needed measurements of the optical properties of LAr, which are essential for both neutrino physics and dark matter communities (some dark matter detectors use LAr detectors). In addition, R&D effort will be dedicated to a new way of instrumenting the LAr detector to detect even more efficiently the particle interactions. The latter could prove to be an innovative way of imaging particle interactions, which could be directly applied to medical imaging, hence of great interest for the medical industries. In the same way several particle physics projects in the past produced great advances in medicine, this research will lay the path to an avant-garde imaging technology that could be use for medical purposes.

The results that will come out of this project will establish the UK at the forefront of the LAr development effort. They will also provide very cost-efficient ways to considerably improve the performance of the LAr detectors for neutrino studies and for the search of the mysterious dark matter. This research will have direct impact on many current and future experiments and could culminate in unravelling some of the greatest mysteries of Science.

Outreach to general public and young students:

This research proposal will provide a great opportunity for particle physics outreach. Neutrinos have attracted a lot of attention in the media recently and the public is now aware of the existence of these mysterious particles. The next generation of neutrino experiments will consists of very large-scale detectors and it is crucial to inform the public of the great relevance of these new experiments. Because this research proposes a new technology for neutrino experiments, it offers a unique way to promote neutrino physics and will pique the curiosity of the public.

Since scientists are now designing the next generation of neutrino detectors, publicizing this science to young people is a perfect way to attract the future scientists in the field of neutrino physics. Liquid Argon detectors will definitely draw attention from young students and we will ensure that neutrino physics is part of the Oxford outreach program.

Medical imaging application:

The current generation of medical imaging techniques requires very high statistics to get an image of sufficient quality for medical diagnostic. Some of the imagers, such as Positron Emission Tomography scanners, require that the patient stays perfectly still for long periods of time, and any movements degrades the image quality greatly. An imager that would offer very good signal-to-noise ratio would allow higher statistics and therefore shorter exposures. This has many advantages such as preserving a good quality of images and increasing the patient comfort.

This research proposes to develop a new technique to instrument Liquid Argon (LAr) detectors. The signal in the detector would be amplified via Gas Electron Multiplier and the amplification signal light (or potentially charge) will be readout by an array of small photon detectors (or potentially charge readout).

While significantly impacting the next generation of neutrino detectors, this particular technique has great potential for medical imaging application. Particle interactions in LAr detectors can be precisely imaged in 3D. They offer high signal-to-noise ratio and with adequate signal amplification, these detectors could also detect low energy particles, which would make them very attractive as medical imagers.

In the past, particle physics projects have often turned into great technological applications and have push considerably medical science. This proposal could be one more example of the success of particle physics research in our every day life.