Infrastructure Request for High Pressure Gas TPC Development Studies for the DUNE Near Detector

Antimatter in the universe is so negligible that our world exists long enough for intelligent life to evolve. But our knowledge says otherwise: By the book, all matter should have obliterated together with antimatter in equal parts. The only key to unlocking this puzzle comes from the behavioural difference between neutrinos and anti(matter-)neutrinos, which can be studied by accelerator-based neutrino experiments. With more powerful accelerators and sophisticated detectors, we are on the way to examining neutrino interactions with unprecedented precision. The Deep Underground Neutrino Experiment (DUNE) is the next-generation neutrino experiment in the US designed to look for the tiny asymmetry between neutrinos and antineutrinos and search rare events that originate from physics beyond the Standard Model of particle physics. DUNE will do this by measuring neutrino oscillations, a phenomenon where neutrinos change type on their way from their production at Fermilab to their detection by the Far Detector (FD) 1200 km away. The DUNE-UK project is the biggest DUNE contribution outside the US and will contribute significantly to the construction of the experiment. It currently focuses on the construction of the DUNE data acquisition (DAQ), FD, and the beamline. The FD modules are planned to be online from 2027, followed by the beams in 2030, and the near detector (ND) in 2032. The ND complex consists of a liquid argon TPC, a High Pressure gas Time Projection Chamber (HPgTPC) enclosed by a solenoid and a calorimeter, and an on-axis beam monitor. This complex is being designed to precisely characterise the neutrino beams and to study neutrino-nucleus interactions with unprecedented details so that the respective systematic errors contributing to the oscillation measurements are much better understood.

The HPgTPC of the DUNE ND, currently being designed, will be the ultimate detector to study neutrino interactions due to its very low detection threshold, full angular acceptance, and very large high-pressure gas volume providing a large target mass. Recently, the Conceptual Design Report has been published, and the Technical Design Report (TDR) is currently being prepared. While the US collaborators are leading the R&D in the magnet and mechanical designs of the HPgTPC, UK institutions are involved in gas studies, readout technology development, design of electronics and DAQ, and in a beam test of the readout chambers.

We propose to build an HPgTPC R&D Platform at the University of Warwick. It consists of three items of prototype equipment:
1. a HPgTPC,
2. a high-performance optical readout system, and
3. a laser-radioactive gas-calibration system.
While we are consolidating our leadership in the field of gas studies and readout technology development with the first two pieces of equipment, the proposed laser calibration system aims to provide a technical solution to the HPgTPC gas quality control that is considered a high priority for the TDR. The Platform in this proposal will provide the only local support for accelerator-neutrino gas TPC R&D in the UK. Capital funding for this proposal would represent a very timely push for further R&D into the HPgTPC concept in the UK and would complement well efforts to extend UK contributions to the DUNE Near Detector project.