Monte Carlo Calculations on Electron Backscattering in Amorphous or Polycrystalline Targets

We propose an application of the Monte Carlo method in the field of backscattering. The results obtained for incident electron energies ranging from 0.3 to 3 MeV and for targets of Al, Cu, Ag and Au are compared with experimental values from several sources. An electron travelling through matter undergoes successive collisions between which it is assumed to travel in a straight line. In our case, we consider the elementary process of interaction electron-nucleus; we have used analytical models for the scattering cross-sections. In order to follow the electron through the specimen, we divide the real trajectory into elements of length much smaller than the mean free path. Pseudo-random number process permits us to determine whether or not an interaction occurs, also the type of interaction. For the energy losses, we introduced a relation derived from Landau\u27s theory. We then followed the electron until it is emerged from the material or halted. The backscattering coefficients obtained for thin and thick targets as a function of the incident electron energy are in good agreement with the experimental data. We have introduced the depth distribution function of the backscattered electrons, which allows us to test the predictions of various theoretical models proposed by other authors

Observation of a nuclear recoil peak at the 100 eV scale induced by neutron capture

Coherent elastic neutrino-nucleus scattering and low-mass Dark Matter detectors rely crucially on the understanding of their response to nuclear recoils. We report the first observation of a nuclear recoil peak at around 112 eV induced by neutron capture. The measurement was performed with a CaWO$_4$ cryogenic detector from the NUCLEUS experiment exposed to a $^{252}$Cf source placed in a compact moderator. The measured spectrum is found in agreement with simulations and the expected peak structure from the single-$\gamma$ de-excitation of $^{183}$W is identified with 3 $\sigma$ significance. This result demonstrates a new method for precise, in-situ, and non-intrusive calibration of low-threshold experiments

Coherent elastic neutrino-nucleus scattering: Terrestrial and astrophysical applications

Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) is a process in which neutrinos scatter on a nucleus which acts as a single particle. Though the total cross section is large by neutrino standards, CE$\nu$NS has long proven difficult to detect, since the deposited energy into the nucleus is $\sim$ keV. In 2017, the COHERENT collaboration announced the detection of CE$\nu$NS using a stopped-pion source with CsI detectors, followed up the detection of CE$\nu$NS using an Ar target. The detection of CE$\nu$NS has spawned a flurry of activities in high-energy physics, inspiring new constraints on beyond the Standard Model (BSM) physics, and new experimental methods. The CE$\nu$NS process has important implications for not only high-energy physics, but also astrophysics, nuclear physics, and beyond. This whitepaper discusses the scientific importance of CE$\nu$NS, highlighting how present experiments such as COHERENT are informing theory, and also how future experiments will provide a wealth of information across the aforementioned fields of physics

Coherent elastic neutrino-nucleus scattering: Terrestrial and astrophysical applications

Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) is a process inwhich neutrinos scatter on a nucleus which acts as a single particle. Thoughthe total cross section is large by neutrino standards, CE$\nu$NS has longproven difficult to detect, since the deposited energy into the nucleus is$\sim$ keV. In 2017, the COHERENT collaboration announced the detection ofCE$\nu$NS using a stopped-pion source with CsI detectors, followed up thedetection of CE$\nu$NS using an Ar target. The detection of CE$\nu$NS hasspawned a flurry of activities in high-energy physics, inspiring newconstraints on beyond the Standard Model (BSM) physics, and new experimentalmethods. The CE$\nu$NS process has important implications for not onlyhigh-energy physics, but also astrophysics, nuclear physics, and beyond. Thiswhitepaper discusses the scientific importance of CE$\nu$NS, highlighting howpresent experiments such as COHERENT are informing theory, and also how futureexperiments will provide a wealth of information across the aforementionedfields of physics.<br

Etude de la transmission et de la rétrodiffusion d'électrons d'énergie 0,05 à 3 MeV dans le domaine de la diffusion multiple

A knowledge of the motion of electrons in matter is of fundamental importance, particularly in scanning microscopy, in microanalysis and in space physics. We present our experimental results for monoenergetic electrons incident normal to polycrystalline targets under multiple scattering conditions. The measurement give information concerning the transmission and backscattering coefficients, the angular distributions and the path-length inside the specimen. We give analytic expressions that describe the experimental results accurately over a very wide range of energies (0.05-3 MeV).Le comportement des électrons dans la matière est d'un intérêt fondamental, notamment en microscopie à balayage, en microanalyse et en physique spatiale. Nous présentons dans cet article l'ensemble de nos résultats expérimentaux dans le domaine de la diffusion multiple pour un faisceau d'électrons monocinétiques tombant normalement sur des cibles polycristallines. Les mesures sont relatives aux coefficients de transmission et de rétrodiffusion, aux distributions angulaires, ainsi qu'au parcours entier des électrons dans la matière. Nous donnons des relations analytiques qui permettent de retrouver avec précision les résultats expérimentaux dans un vaste domaine énergétique (0,05 à 3 MeV)

Transmission et rétrodiffusion d'électrons de haute énergie : dispositif expérimental et modèles analytiques

A knowledge of electron behaviour in the matter is needed, from a fundamental point of view in scanning electron microscopy, electron microanalysis and in source fields of space physics. The transmission and backscattering coefficients of amorphous and polycrystalline samples bombarded with monoenergetic electron beams are presented. A completely automated apparatus designed for measuring the coefficients is described. Semi-empirical laws have been established. These accurately describe the experimental results for energies ranging from 0.5 to 30 MeV.La microscopie à balayage, la microanalyse, la physique spatiale ont besoin, d'un point de vue fondamental, de connaître le comportement des électrons dans la matière. Nous présentons dans cet article les coefficients de transmission et de rétrodiffusion de cibles amorphes ou polycristallines bombardées par un faisceau d'électrons monocinétiques. Nous décrivons l'appareillage entièrement automatisé, conçu et mis au point pour la mesure de ces coefficients caractéristiques. Nous donnons des lois semi-empiriques qui permettent de retrouver avec précision les résultats expérimentaux dans un vaste domaine énergétique (0,05 à 30 MeV)