Modelization and impact of electric field distorsions on the DUNE Long Baseline Neutrino program
IDPASC Portugal - PHD Programme 2019
2019 / 2020
Experimental Particle Physics
Instituto Superior Técnico
Laboratório de Instrumentação e Física Experimental de Partículas
The DUNE experiment is a next generation neutrino experiment currently under development to be deployed at SURF in Lead, South Dakota. By using the broad- band neutrino beam from LBNF at Fermilab, DUNE’s main goal is to determine 1the neutrino mass hierarchy and the observation of leptonic CP violation. The primary technology employed by the experiment consists of a liquid argon TPC, which allows the experiment to not only have unparalleled imaging capabilities, but also have a rich physics program beyond the main accelerator neutrino program, including low energy neutrinos, nucleon decay, atmospheric neutrinos and be sensitive to neutrinos of supernavae within this and nearby galaxies. A prototype program is currently being pursued at CERN with two cryostats of 1kt that will be used to study events from cosmic rays and from a proton beam that will permit to produce the final states of the major neutrino interactions expected in DUNE. One of the main challenges of this technology consists in the proper modeling of the detector response and the various effects that affect it. The particle signal is built from argon ionization whose positive ions and electrons derive in opposite directions, pushed by the large electric field applied. The knowledge of the field is of paramount importance for the reconstruction accuracy and distortions of the electric field in the cryostat can be caused by accumulation of slow argon ions. ProtoDUNE, installed at the earth surface, benefit from the large number of muons crossing it thus providing straight calibration tracks. This thesis will use the cosmic ray events taken in the first run of the experiment to understand the so-called space-charge effects. This will permit to calibrate the detector in the whole volume, improving its response and therefore reducing the systematic uncertainties in the event reconstruction. In a later phase, planned to 2021, a dedicated calibration system based on a powerful laser able to ionize argon will be developed and deployed. The thesis plan will include working with the dedicated calibration system, contribute to the development of DUNE calibration strategy by comparing the electric field distorsions obtained with two complementar methods from the cosmic muon analysis and the laser system.