arXiv subjects

Luca Egoriti

Publications and source records attributed to Luca Egoriti.

4 recordsLinked to original sources

arXiv2023

Ion-Implanted $^8$Li Nuclear Magnetic Resonance in Highly Oriented Pyrolytic Graphite

We report $β$-detected nuclear magnetic resonance of ultra-dilute $^{8}$Li$^{+}$ implanted in highly oriented pyrolytic graphite (HOPG). The absence of motional narrowing and diffusional spin-lattice relaxation implies Li$^+$ is not appreciably mobile up to 400 K, in sharp contrast to the highly lithiated stage compounds. However, the relaxation is remarkably fast and persists down to cryogenic temperatures. Ruling out extrinsic paramagnetic impurities and intrinsic ferromagnetism, we conclude the relaxation is due to paramagnetic centers correlated with implantation. While the resulting effects are not consistent with a Kondo impurity, they also differ from free paramagnetic centers, and we suggest that a resonant scattering approach may account for much of the observed phenomenology.

cond-mat.mtrl-sci↗

arXiv2023

Direct mass measurements of neutron-rich zinc and gallium isotopes: an investigation of the formation of the first r-process peak

The prediction of isotopic abundances resulting from the rapid neutron capture process (r-process) requires high-precision mass measurements. Using TITAN's on-line time-of-flight spectrometer, first time mass measurements are performed for $^{83}$Zn and $^{86}$Ga. These measurements reduced uncertainties, and are used to calculate isotopic abundances near the first r-process abundance peak using astrophysical conditions present during a binary neutron star (BNS) merger. Good agreement in abundance across a range of trajectories is found when comparing to several metal-poor stars while also strongly deviating from the solar r-process pattern. These findings point to a high degree of sensitivity to the electron fraction of a BNS merger on the final elemental abundance pattern for certain elements near the first r-process peak while others display universality. We find that small changes in electron fraction can produce distinct abundance patterns that match those of metal-poor stars with different classifications.

nucl-ex↗

arXiv2019

Material development towards a solid 100 kW electron-gamma converter for TRIUMF-ARIEL

A series of irradiation tests have been performed at TRIUMF to investigate different material pairings to act as high-power electron-to-gamma converter for the ARIEL Electron Target East (AETE). The bulk of the converter body will be made out of an aluminum alloy with a sub-millimeter high-Z metal layer bonded to the surface facing the incoming electron beam. This contribution presents the approach chosen to select the optimal material for the high-Z layer, describes the tests performed and shows result which led to the successful selection of a specific tantalum-aluminum pairing as the future ARIEL converter material.

physics.acc-ph↗

arXiv2016

Analytical model for release calculations in solid thin-foils ISOL targets

A detailed analytical model has been developed to simulate isotope-release curves from thin-foils ISOL targets. It involves the separate modelling of diffusion and effusion inside the target. The former has been modelled using both first and second Fick's law. The latter, effusion from the surface of the target material to the end of the ionizer, was simulated with the Monte Carlo code MolFlow+. The calculated delay-time distribution for this process was then fitted using a double-exponential function. The release curve obtained from the convolution of diffusion and effusion shows good agreement with experimental data from two different target geometries used at ISOLDE. Moreover, the experimental yields are well reproduced when combining the release fraction with calculated in-target production.

physics.comp-ph↗