Conical liquid noble gas apparatus for neutrino physics.

Coherent elastic neutrino-nucleus scattering (CEνNS) is a recently demonstrated novel process of neutrino interaction. It provides numerous avenues to advance our sensitivity to new physics beyond the Standard Model and enables a miniaturization of otherwise massive neutrino detectors, opening up the possibility of technological applications.The development the development of an innovative single-phase noble liquid time projection chamber (TPC) to detect CEνNSis proposed. Two distinct ideas are combined to maximize the potential of the technique. 1) The signal will be amplified through electroluminiscence (EL). 2) The TPC will be shaped as a conical frustum. Single-phase EL is unaffected by charge trapping which is the major deterrent of dual-phase noble liquid TPCs for CEνNS searches at shallow depths. However, it requires extremely high electric fields. Such fields can be reached by using very thin wires – μm-scale diameter. This is an impediment to produce large amplification regions. Common TPC shapes are thus limited in size and target mass. The conical shape allows to maximize the mass by drifting all charges towards a small amplification region at the smaller circle of the cone. Such scheme allows for good coverage with few sensors.COLINA, a conical TPC capable of holding ∼50 kg of LXe, will be developed and deployed at the largest spallation neutrino source, the European Spallation Source. Simulations point to a conservative energy threshold as low as ∼0.525 keVnr. The detector will allow for operation with different noble gases. The increase in density of liquid-phase, compared to gaseous-phase, results in large CEνNS rate with rather small detectors. In fact, COLINA will produce the larger CEνNS statistics in all the considered isotopes, Xe, Kr and Ar, and will do so in unexplored energy regions for the process, where the physics relevance is maximal.