Thesis

Anti-neutrino oscillations with SNO+

• Call:

  IDPASC Portugal - PHD Programme 2019

• Academic Year:

  2019 / 2020

• Domain:

  Experimental Particle Physics

• Supervisor:

  Sofia Andringa

• Co-Supervisor:

  José Maneira

• Institution:

  Faculdade de Ciências - Universidade de Lisboa

• Host Institution:

  Laboratório de Instrumentação e Física Experimental de Partículas

• Abstract:

  SNO+ is a detector located 2000 m underground in Canada, which is now being filled with liquid scintillator, boosting the measurement of anti-neutrinos created by natural radioactivity of the Earth and by nuclear reactors. It will do a a first measurement of geo-neutrinos from the North-American crust, useful to constrain global Earth models. Moreover, due to the distribution of nuclear reactors around SNO+, neutrino oscillations will induce clear features on the detectable energy spectrum. For one of the squared mass differences between neutrino states, SNO+ is expected to reach a precision comparable to the only other existing such measurement. Recent results from solar neutrinos prefer slightly different values of this parameter, increasing the impact of the measurement in the global precision in neutrino physics. The expected rates of anti-neutrinos are small, but they can be identified by the delayed coincidence of a positron annihilation followed by a neutron capture. The positron energy and the neutron initial direction follow the anti-neutrino kinematics. The proposed work plan will involve all aspects of the anti-neutrino data analysis. The detector response will be characterized with a neutron calibration source that mimics the delayed coincidence signature. The time and spacial evolution of similar radioactive backgrounds will be monitored. Methods will be explored to separate positrons from the most common alpha and gamma events. This program will lead to the precise measurement of the energy spectrum of anti-neutrinos, from which the neutrino oscillation parameters will be extracted. The program is well fitted to the responsibilities of the LIP group within SNO+. Participation in in-situ activities in SNOLAB will be required.