Neutrino Physics
DUNE:
Deep Underground Neutrino Experiment
The Deep Underground Neutrino Experiment is an international flagship experiment to unlock the mysteries of neutrinos. DUNE will be installed in the Long-Baseline Neutrino Facility, under construction in the United States. The neutrinos produced at the Fermi National Accelerator Laboratory (Illinois) with the most powerful neutrino beam ever constructed will travel 1200 km underground to reach 4 gigantic detectors positioned 1 mile underground at the Homestake mine in South Dakota.
DUNE will pursue three major science goals: find out whether neutrinos could be the reason the universe is made of matter by measuring CP-violation in the neutrino sector; look for subatomic phenomena that could help realize Einstein’s dream of the unification of forces; and watch for neutrinos emerging from an exploding star, perhaps witnessing the birth of a neutron star or a black hole.
Set to take data in the late 2020s, the experiment is currently under construction. The first two detectors in South Dakota will be based on the Liquid Argon Time Projection Chamber (LArTPC) technology. The heart of the massive DUNE detectors is the charge-sensitive anode plans, made of hundreds of thousands of wires. The Manchester Particle Physics group currently hosts the only Anode Plane Assembly (APA) factory in the UK where the anode planes are constructed. Prof. Evans as Technical Lead of APA. All the neutrino faculty are involved in DUNE, with different areas of interest.
The Short-Baseline Neutrino Program
The Short-Baseline Neutrino Program at Fermilab measures properties of neutrinos, particularly how neutrinos’ flavor changes during their propagation through space and matter. The main objectives of the program are to address the long-standing puzzle of short-baseline neutrino anomalies, to characterize neutrino interactions in argon and to search for new physics in neutrino beams and cosmi ray data.
The program employs three distinct detectors (SBND, MicroBooNE and ICARUS), all based on the LArTPC technology, but at different life stages. SBND is currently under construction and will start commissioning in 2022, MicroBooNE has completed data-taking and in full data analysis-mode. ICARUS is currently taking data.
Manchester leads a number of MicroBooNE’s physics analysis, with Prof. Evans being the current MicroBooNE spokesperson. Analysis topics range from oscillation physics (Evans, Guenette, Gramellini), to cross-section (Guenette, Gramellini), to beyond the standard model searches in the beam (Evans) and in the cosmics (Gramellini). Manchester is also involved in the SBND construction and commissioning.
MicroBooNE is located 470 meters from the Booster Neutrino Beam target, and consists of a 8250-wire TPC and 32 photomultiplier tubes which instrument 80 tons of liquid argon in the active volume. The cryostat was filled in 2015.
Short-Baseline Near Detector, or SBND, is located just 110 meters from the Booster Neutrino Beam target, and has 112 tons of liquid argon within the active volume of its detection systems. The SBND cryostat is a membrane type, the same as planned for the future DUNE far detectors. With 2 APAs and TPC installation, Manchester is leading SBND construction.
The NEXT Experiment
The Neutrino Experiment with a Xenon TPC (NEXT) experiment is an international collaboration looking for neutrinoless double-beta decay. If observed, this extremely rare decay would be a definitive proof of the Majorana nature of neutrinos. The NEXT experiment is located at the Canfranc Underground Laboratory (LSC) in Canfranc, Huesca (Spain), under mount Tobazo.
The detection concept consists in a Time Projection Chamber filled with high-pressure gaseous Xenon (HPXe-TPC) that exploits the Electroluminescence effect, with separated-function capabilities for calorimetry and tracking. The NEXT project is developed in several stages with progressively increasing active volume prototypes.
Prof. Guenette is the Project Manager for the NEXT-100 TPC.
SuperNEMO
The NEMO (Neutrino Ettore Majorana Observatory) collaboration is an international collaboration including the experiment SuperNEMO and its predecessor, NEMO-3, to search for neutrinoless double beta decay.
The SuperNEMO Demonstrator Module is located at the Laboratoire Souterrain de Modane, in the Fréjus tunnel in the French Alps.
The Demonstrator Module has a tracker-calorimeter architecture, with a thin layer of ββββ-emitting isotope sandwiched between trackers and surrounded by calorimetry. This allows for a full three-dimensional reconstruction of charged particle tracks, as well as energy measurements. The SuperNEMO experiment brings a unique full-topological reconstruction capability to the search for neutrinoless double-β decay (0νββ).
Manchester built the detector’s 2,034 Geiger cells, comprising 14,000 wires, that make up the SuperNEMO tracker. The group also designed the tracker front-end electronics and the tracker high-voltage supply and regulation system, and currently continues to lead the collaboration in the exploitation of data from the NEMO-3 experiment, developing advanced analysis techniques that will lead to new measurements with SuperNEMO.
New Neutrino Detectors:
Research & Development
Under a ERC Synergy grant, the Manchester group is developing new technologies for future generation of detectors, especially in the context of noble element detectors. Currently, the group is focused on developing new photodetector concepts (Metalenses and LILAr) and new charge readouts (Q-Pix). Small scale R&D is the first step in building the next generation of neutrino detectors.
Metalenses are nanostructures that focus light, allowing for a cost-effective
solution to increase the light collection while maintaining a reasonable number of photosensors in noble element detectors.
Prof. Guenette works to develop an application of metalenses for VUV light detection.
The Light Imaging in Liquid Argon (LILAr) project aims to develop coatings of amorphous selenium for the detection of VUV light in noble element detectors with high quantum efficiency in wide surface detectors.
Dr. Gramellini is spearheading the project.
QPix is a novel ionization readout and waveform digitization scheme to pixelate kiloton-scale LArTPC detectors. The scheme is based on a pixel-scale self-triggering `charge integrate/reset’ block, local clocks running at unconstrained frequencies and dynamically established data networks. Both As part of the QPix consortium, Prof. Guenette and Dr. Gramellini are in the process of building the “Pixel Lab”: a University of Manchester space for the development of pixelated TPC technology.
The Group (Gramellini, Guenette) is also developing a new fully pixelated light-charge readout concept for the detection of low-energy solar or supernova neutrinos.