PhD in neutrino physics - Dune experiment (M/F)

Job Description

Thesis Subject

This thesis offer within the AstroParticle and Cosmology Laboratory (APC) is part of the Deep Underground Neutrino Experiment (DUNE). DUNE is an international neutrino experiment under development, hosted in the United States, that brings together the efforts of more than 1400 scientists and engineers from more than 200 institutions around the world. Designed primarily as a neutrino oscillation experiment, it aims to deepen our knowledge of this phenomenon, including determining the mass order of neutrinos, measuring the phase of charge-parity symmetry violation (if it is non-zero), improving the accuracy of oscillation parameters, and testing the three-flavor paradigm. To do this, the world's most intense neutrino beam is being built at FNAL (Fermilab), and 1300 km away, deep underground, at the Sandford Underground Research Facility (South Dakota), four gigantic distant detector modules are planned. These modules are liquid argon time projection chambers (LArTPC), each containing 17 kilotonnes of liquid argon. Thanks to its colossal and well-shielded detectors, DUNE can expand its field of study and analyze neutrinos from sources other than the beam.

The APC team is interested in studying atmospheric neutrinos, produced in the Earth's upper atmosphere, which pass through the planet and can interact with DUNE's distant detectors. The atmospheric sample covers a wide range of energies, encompassing that of the DUNE beam (about 0.8 to 10 GeV), and can also be used to study neutrino oscillations, providing sensitivity to the neutrino mass order and the θ₂₃ mixing angle. Neutrinos with energies less than 1 GeV (sub-GeV) have also been shown to offer sensitivity to the CP violation phase.

The DUNE Distant Detectors are state-of-the-art instruments, the largest LArTPC ever designed. The experiment is conducting an ambitious prototyping programme to validate this ever-evolving technology, hosted on CERN's neutrino platform, on a large scale. Two detectors, called protoDUNEs, were built and allowed to test three different reading technologies. Two technologies have been selected for the first two remote sensor modules: the first, wire-based, and the second, PCB-based. Neutrinos are detected through their interactions with argon nuclei within the LArTPC. These interactions release energetically charged particles that ionize and excite liquid argon. The electrons are moved by an electric field applied to three reading planes oriented at different angles, where they induce signals. LArTPCs can produce highly accurate 3D images of neutrino events, which can span several meters. These instruments produce large amounts of data that require several processing steps before the relevant physical variables are obtained. Typically, machine learning methods are used to optimize performance.

At CERN, protoDUNES are characterised using beams of charged particles, which makes it possible to study the detector's response to these particles, such as electrons, muons, protons, pions, etc. However, these test beams can only collect a very small number of neutrinos.

This PhD is funded by a joint UChicago-CNRS project entitled "Exploiting Liquid Argon Instruments for sub-GeV Neutrinos" (ELAIN), which brings together the DUNE team from the APC and a team from the University of Chicago working on the Short Baseline Near Detector (SBND) detector of the FNAL. SBND is an LArTPC similar in design to DUNE's Horizontal Drift instrument, located 110 meters from the neutrino beam target and recording more than one million neutrino events per year. The project aims to use the real neutrino interaction data recorded by SBND to study the performance of DUNE against atmospheric low-energy (sub-GeV) neutrinos. In this context, the proposed thesis will focus on the reconstruction of events in DUNE, in close collaboration with the University of Chicago team.

Your Work Environment

The work consists of the analysis of data, simulated and real, in order to:

- Study existing reconstruction methods in DUNE, using both simulations and charged particle beam data from protoDUNES
- Compare the performance obtained with single-trace events in the protoDUNE and SBND detectors
- Study the reconstruction of neutrino events using the simulation of the DUNE distant detector and compare the expected performance of DUNE to low-energy neutrino interactions with SBND
- Estimate the systematic uncertainties related to the reconstruction, in particular those that have the greatest impact on the determination of the oscillation parameters with the atmospheric sample
Regular remote meetings will be organised between the APC team and the University of Chicago team, as well as face-to-face meetings in Paris and CERN, and annual visits to Chicago

A strong interest in computer science (software development, machine learning techniques, etc.) is desirable.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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