Fonctionne avec Indico
v3.2.8
Radiotherapy uses high energy beams of photons or charged particles to treat diseases such as cancer. About half of all cancer patients will receive some form of radiotherapy during their treatment, with the goal of the treatment being to effectively destroy cancer cells whilst sparing the surrounding healthy tissues. Accurate dosimetry and beam monitoring is required to ensure the quality of the treatment and reduce undesirable side effects. Novel radiotherapy techniques based on spatial fractionation of the dose and/or ultra-high dose rates have demonstrated decreased normal tissue complications whilst maintaining or even increasing tumour control, however, present challenges for accurate dosimetry and beam monitoring. In this talk I will present my previous work on the development and characterisation of detectors for dosimetry or online beam monitoring of these novel radiotherapy techniques and introduce my current work at the LPSC.
Cosmology has undergone a revolution in the last few decades, driven by advancements in observational techniques, theoretical models and computational capabilities. Among its most significant achievements is the establishment of $\Lambda$CDM as the standard cosmological model. $\Lambda$CDM describes the Universe as composed mainly of dark energy in the form of a cosmological constant, $\Lambda$; cold dark matter (CDM); and ordinary baryonic matter. Each of these constituents account for a 70%, 25% and 5% of the total energy density of the Universe, respectively. Large galaxy surveys, such as the Dark Energy Survey (DES), have played a pivotal role in increasing our understanding of cosmology within the $\Lambda$CDM framework. One of the key cosmological probes used by these surveys is the measurement of the baryon acoustic oscillations (BAO), which are imprints of primordial sound waves from the early Universe that left characteristic features in the large-scale distribution of matter. The BAO serves as a ``standard ruler'' in cosmology, providing precise measurements of cosmic distances that can be used to constrain cosmological parameters. This talk focuses on one of my Ph.D. projects, which is about measuring the BAO distance scale using the first three years of data of the DES (DES Y3). I will describe the different steps of the analysis, the results obtained and their implications.
Leading cosmological surveys and models provide strong indications for cold Dark Matter (DM) being a major constituent of our Universe. However, direct observation of the hypothesized galactic flux of DM particles streaming through the Earth remains an open quest. The SuperCDMS collaboration is currently constructing a Generation-2 direct DM search experiment at the SNOLAB underground facility in Sudbury, Canada. It will employ two types of state-of-the-art cryogenic Ge and Si detectors capable of detecting sub-keV energy depositions. The unique mix of target substrates and detector technologies allows for a simultaneous study of intrinsic and external backgrounds as well as exploring the DM mass range below 10 GeV/c2 with world-leading sensitivity. In order to extend the sensitivity to lower DM masses, a precise understanding of the detector response down to the semiconductor bandgap energy is needed. This effort is driven by an active R&D detector program and comprehensive prototype detector measurements at cryogenic test facilities. In addition, a sophisticated Detector Monte-Carlo has been developed to guide the data analysis and model building. This talk will present an overview of our detector technology and recent milestones towards science operation with SuperCDMS at SNOLAB.