Ph.D. Candidate (M/F): Position calibration of KM3NeT neutrino telescopes using and optimizing dedicated acoustic systems.

Job Description

Thesis Subject

Topic: Position and orientation calibration of KM3NeT neutrino telescopes: operation and performance optimization of dedicated acoustic systems.

Scope of Work: As part of this thesis project, we propose to leverage the new infrastructure (long-distance networks) soon to be deployed and upcoming acoustic measurement campaigns (using on-board transmitters) to determine the absolute positions and orientations of the telescopes and thereby improve their angular resolution. The work will also involve prototyping and testing new methods for filtering acoustic data for integration into the real-time system, with the aim of significantly improving the current temporal resolution of the signals and, consequently, the relative positioning (static and dynamic) of the ORCA and ARCA telescopes. Additional constraints on the mechanical model describing the detection lines are then expected, allowing for its refinement. In this context, the student is expected to play a significant role in determining the relative positions of the various telescope configurations throughout the contract. Finally, an effort will be undertaken to design, develop, and refine a software suite for modeling the propagation of acoustic signals in the instrument environment and for simulating the operation of the equipment used to receive and filter these signals. These tools will enable us to validate ongoing studies on the position and orientation resolutions of the instruments, as well as to predict their asymptotic values and, more generally, to understand and explore their acoustic environments (both continuous and impulsive).
This work is part of the growth momentum of the KM3NeT group at the SUBATECH laboratory, driven by recent reinforcements, and notably reflects a commitment to making a significant contribution in the fields of computer science (software, environment, computation, real-time acquisition), acoustic calibration, and the detection and analysis of astrophysical neutrinos using KM3NeT telescopes. The student will interact closely with everyone involved (students, researchers, engineers) in the project in Nantes, as well as with other research teams within the KM3NeT collaboration engaged in instrument construction in France and across Europe.

Your Work Environment

KM3NeT is a neutrino observatory currently under construction in the Mediterranean Sea. Two deep-water volumes are being progressively instrumented through the deployment of vertical lines equipped with optical modules to form the ORCA and ARCA telescopes. These instruments detect the faint light induced by the interaction of high-energy neutrinos within their volume or in their vicinity. The direction of arrival of these neutrinos is one of the key parameters derived from the instruments, and its precision is a major factor in achieving the intended scientific objectives.

The observation of the ultra-high-energy neutrino KM3-230213A by the ARCA telescope has revealed both the full potential of this instrument for astronomy and the work that remains to be done to achieve its full capabilities. The error in the telescope's absolute orientation is the primary source of uncertainty in the event coordinates and has so far prevented the reduction of the large number of known astrophysical sources that could potentially emit this neutrino. It is therefore a key characteristic of the detector that must be constrained in order to distinguish between an astrophysical source and a cosmological origin for the production of this neutrino.
The calibration of the instruments' position and orientation relies on specific acoustic systems that are also being finalized in parallel with the optical sensors. These systems involve receivers installed in the optical modules that record acoustic signals (ranging from a few kHz to several tens of kHz) from a set of nearby or distant transmitters placed on the seafloor or mounted on a vessel occasionally passing over the telescopes.


The candidate must:
- hold a master's degree or equivalent in Physics in one or more of the following fields: instrumentation, signal processing, scientific computing, and modeling. Knowledge of acoustic signal propagation in the marine environment would be appreciated.
The candidate must:
- demonstrate strong motivation, curiosity, and independence,
- be fluent in English,
- be able to write scientific reports and present results orally to an international audience,
- be able to work both independently and collaboratively within an international team environment.

References:
· The KM3NeT web site : https ://www.km3net.org
· KM3NeT 2.0 – Letter of Intent for ARCA and ORCA, The KM3NeT Collaboration: S. Adrián-Martínez et al. J. Phys. G: Nucl. Part. Phys. 43 (2016) 084001
· Observation of an ultra-high-energy cosmic neutrino with KM3NeT. The KM3NeT Collaboration, Nature 638, 376–382 (2025)

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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