The ThomX project status

Work supported by the French Agence Nationale de la recherche as part of the program EQUIPEX under reference ANR-10-EQPX-51, the Ile de France region, CNRS-IN2P3 and Université Paris Sud XI - http://accelconf.web.cern.ch/AccelConf/IPAC2014/papers/wepro052.pdfA collaboration of seven research institutes and an industry has been set up for the ThomX project, a compact Compton Backscattering Source (CBS) based in Orsay - France. After a period of study and definition of the machine performance, a full description of all the systems has been provided. The infrastructure work has been started and the main systems are in the call for tender phase. In this paper we will illustrate the definitive machine parameters and components characteristics. We will also update the results of the different technical and experimental activities on optical resonators, RF power supplies and on the electron gun

Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

Paramagnetism and specific heat of the graphite lamellar compound C6Li

The alkali-metal graphite lamellar compounds C8M with M = K, Rb, Cs are well known. In the first stage intercalation compounds the occurence of superconductivity, below 1 K, has been reported [1] and discussed [2] but not confirmed [3]. A lamellar compound with lithium was studied a long time ago [4] but only recently was it synthesized with a well-defined stoichiometry (C6Li) [5]. In order to understand the electronic structure of this metallic compound and to examine the possible existence of superconductivity the physical properties at thermal equilibrium, namely static susceptibility, E.P.R., and specific heat have been examined at temperatures down to 1.5 K.Les composés lamellaires du graphite C8M (M = K, Rb, Cs) sont bien connus; l'apparition de la supraconductivité au-dessous de 1 K a été signalée [1] discutée [2] mais pas confirmée [3]. Un composé lamellaire avec du lithium a déjà été étudié [4] mais préparé avec une stœchiométrie bien définie récemment (C6Li) [5]. Pour comprendre la structure électronique de ce composé métallique et examiner la possibilité d'apparition d'un état supraconducteur, les propriétés physiques à l'équilibre : magnétisme statique, R.P.E., et chaleur spécifique ont été étudiées jusqu'à 1,5 K

L'infarctus du myocarde post-traumatique au cours du sport : une entité originale ? : A propos d'un cas clinique et revue de la littérature

Observation d'un cas d'infarctus du myocarde à la suite d'un choc thoracique, dû à une chute en compétition chez un skieur de fond de 23 ans. Revue de la littérature : épidémiologie des infarctus d'effort et des atteintes myocardiques post-traumatiques; examen du rôle des traumatismes thoraciques dans la survenue d'infarctus au cours de la pratique sportive à partir d'une revue sur dossier

Doping Liquid Argon with Xenon in ProtoDUNE Single-Phase: Effects on Scintillation Light

International audienceDoping of liquid argon TPCs (LArTPCs) with a small concentration of xenon is a technique for light-shifting and facilitates the detection of the liquid argon scintillation light. In this paper, we present the results of the first doping test ever performed in a kiloton-scale LArTPC. From February to May 2020, we carried out this special run in the single-phase DUNE Far Detector prototype (ProtoDUNE-SP) at CERN, featuring 770 t of total liquid argon mass with 410 t of fiducial mass. The goal of the run was to measure the light and charge response of the detector to the addition of xenon, up to a concentration of 18.8 ppm. The main purpose was to test the possibility for reduction of non-uniformities in light collection, caused by deployment of photon detectors only within the anode planes. Light collection was analysed as a function of the xenon concentration, by using the pre-existing photon detection system (PDS) of ProtoDUNE-SP and an additional smaller set-up installed specifically for this run. In this paper we first summarize our current understanding of the argon-xenon energy transfer process and the impact of the presence of nitrogen in argon with and without xenon dopant. We then describe the key elements of ProtoDUNE-SP and the injection method deployed. Two dedicated photon detectors were able to collect the light produced by xenon and the total light. The ratio of these components was measured to be about 0.65 as 18.8 ppm of xenon were injected. We performed studies of the collection efficiency as a function of the distance between tracks and light detectors, demonstrating enhanced uniformity of response for the anode-mounted PDS. We also show that xenon doping can substantially recover light losses due to contamination of the liquid argon by nitrogen