Optimization of gamma radiation detectors for medical imaging. Time-of-flight positron emission tomography

Positron emission tomography (PET) is a nuclear medical imaging technique widely used in oncology and neurobiology.
We're proposing you to contribute to the development of an ambitious, patented technology: ClearMind. This gamma photon detector uses a monolithic PbWO4 crystal, in which Cherenkov and scintillation photons are produced. These optical photons are converted into electrons by a photoelectric layer and multiplied in a MicroChannel plate. The induced electrical signals are amplified by gigahertz amplifiers and digitized by SAMPIC fast acquisition modules. The opposite side of the crystal will be fitted with a matrix of silicon photomultiplier (SiPM).

You will work in an advanced instrumentation laboratory in a particle physics environment .
The first step will be to optimize the "components" of ClearMind detectors, in order to achieve nominal performance. We'll be working on scintillating crystals, optical interfaces, photoelectric layers and associated fast photodetectors, and readout electronics.
We will then characterize the performance of the prototype detectors on our measurement benches.
The data acquired will be interpreted using in-house analysis software written in C++ and/or Python.
Finally, we will compare the physical behavior of our detectors to Monté-Carlo simulation software (Geant4/Gate).
A particular effort will be devoted to the development of ultra-fast scintillating crystals in the context of a European collaboration.

MEASUREMENT OF THE W-BOSON MASS WITH THE ATLAS DETECTOR AT THE LHC

The objective of the thesis is a precise measurement of the mass and width of the W boson, by studying its leptonic decays with the ATLAS detector at the LHC. The analysis will be based on data from Run 2 of the LHC, and aims for an precision on the mass of 10 MeV.

The candidate will be involved in the study of the alignment and calibration of the ATLAS muon spectrometer. IRFU played a leading role in the design and construction of this instrument and is heavily involved in its scientific exploitation. This will involve optimally combining the measurement given by the spectrometer with that of the ATLAS inner detector, using a precise model of the magnetic field and the relative positioning of these systems, in order to reconstruct the muon kinematics with the precision required for measurement.

The second phase of the project consists of improving the modeling of the W-boson production and decay process and optimizing the analysis itself in order to minimize the final uncertainty of the measurement. The measurement result will be combined with other existing measurements, and interpreted in terms of compatibility with the Standard Model prediction or as an indication of the presence of new physics.