Infrastructure for Detector Research and Development towards the International Linear Collider

The EUDET-project was launched to create an infrastructure for developing and testing new and advanced detector technologies to be used at a future linear collider. The aim was to make possible experimentation and analysis of data for institutes, which otherwise could not be realized due to lack of resources. The infrastructure comprised an analysis and software network, and instrumentation infrastructures for tracking detectors as well as for calorimetry.Comment: 54 pages, 48 picture

Response of a CMS HGCAL silicon-pad electromagnetic calorimeter prototype to 20-300 GeV positrons

The Compact Muon Solenoid Collaboration is designing a new high-granularity endcap calorimeter, HGCAL, to be installed later this decade. As part of this development work, a prototype system was built, with an electromagnetic section consisting of 14 double-sided structures, providing 28 sampling layers. Each sampling layer has an hexagonal module, where a multipad large-area silicon sensor is glued between an electronics circuit board and a metal baseplate. The sensor pads of approximately 1 cm$^2$ are wire-bonded to the circuit board and are readout by custom integrated circuits. The prototype was extensively tested with beams at CERN's Super Proton Synchrotron in 2018. Based on the data collected with beams of positrons, with energies ranging from 20 to 300 GeV, measurements of the energy resolution and linearity, the position and angular resolutions, and the shower shapes are presented and compared to a detailed Geant4 simulation

Performance of the CMS High Granularity Calorimeter prototype to charged pion beams of 20−-300 GeV/c

The upgrade of the CMS experiment for the high luminosity operation of the LHC comprises the replacement of the current endcap calorimeter by a high granularity sampling calorimeter (HGCAL). The electromagnetic section of the HGCAL is based on silicon sensors interspersed between lead and copper (or copper tungsten) absorbers. The hadronic section uses layers of stainless steel as an absorbing medium and silicon sensors as an active medium in the regions of high radiation exposure, and scintillator tiles directly readout by silicon photomultipliers in the remaining regions. As part of the development of the detector and its readout electronic components, a section of a silicon-based HGCAL prototype detector along with a section of the CALICE AHCAL prototype was exposed to muons, electrons and charged pions in beam test experiments at the H2 beamline at the CERN SPS in October 2018. The AHCAL uses the same technology as foreseen for the HGCAL but with much finer longitudinal segmentation. The performance of the calorimeters in terms of energy response and resolution, longitudinal and transverse shower profiles is studied using negatively charged pions, and is compared to GEANT4 predictions. This is the first report summarizing results of hadronic showers measured by the HGCAL prototype using beam test data.Comment: To be submitted to JINS

Les niveaux d'énergie des atomes de numéro atomique inférieur à 70

Cet article fait suite à une précédente publication (J. Physique Rad., I952, 13, II3). Il présente un tableau des niveaux d'énergie des atomes de numéro atomique 69 à 3 inclusivement, calculés à partir de leurs fréquences X caractéristiques. Jusqu'au numéro atomique 37 inclusivement, la fréquence de la transition qui sert de base aux calculs est celle de la discontinuité LIII, comme pour les éléments plus lourds. Au delà, le zéro des énergies change légèrement puisque c'est la fréquence dela discontinuité d'absorption K qui a été choisie comme base des calculs. Sous réserve de quelques nouvelles mesures spectroscopiques à effectuer, on obtient probablement ainsi la tabulation la plus satisfaisante quant à l'homogénéité et à la précision des données présentées. L'extension du tableau aux éléments dont les spectres X sont incomplets ou inconnus, y compris les transuraniens, sera publiée prochainement

RAPPEL DE QUELQUES DONNÉES GÉNÉRALES SUR LES SPECTRES X

L'article rappelle quelques données générales sur les spectres X : en particulier, les expressions de l'énergie d'un niveau atomique et le rôle de la liaison chimique sur sa valeur exacte. Vers ou à partir d'un tel niveau se produisent des transitions qui, mettant en jeu les distributions d'états d'énergie propres au solide où l'atome est lié, présentent un intérêt très direct pour l'analyse du comportement des électrons dans ce solide, spécialement pour l'observation des bandes d'énergie dans les isolants. Les « excitons » associés aux niveaux atomiques, évoqués par N. F. Mott en liaison avec le processus d'absorption X, sont comparés aux excitons optiques, mobiles, associés aux niveaux du solide. L'importance relative des résultats de la spectroscopie X et les soins à y apporter, sont discutés succinctement.This article recalls some general data on X-ray spectra and, in particular, the expressions for the energy of an atomic level and the influence of the chemical bond on its exact value. Transitions occur towards or from these levels which involve the distribution of energy states peculiar to the solid where the atom is bound. This is of direct interest in the study of the behaviour of electrons in the solid and especially in that of the energy bands in insulators. The « excitons » associated with the atomic levels suggested by N. F. Mott in connection with X-ray absorption processes are compared with mobile optical excitons related to the levels belonging to the solid. A brief discussion is presented on the relative importance of the results given by X-ray spectroscopy and the care which must be taken in obtaining them