arXiv subjects

Michael Leyton

Publications and source records attributed to Michael Leyton.

5 recordsLinked to original sources

arXiv2022

Experimental study of the positive ion feedback from gas to liquid in a dual-phase argon chamber and measurement of the ion mobility in argon gas

The dynamics of the positive ions created by particle interactions inside argon time projection chambers plays an important role in characterizing the next generation of massive detectors planned for the direct search for dark matter and the study of neutrino properties. We have constructed a 1 L liquid argon chamber (ARION: ARgon ION experiment) with a high voltage pulse generator capable of injecting, in a controlled manner, a sizeable ion current into the drift region. This chamber is capable of reproducing a volume charge similar to that found in large detectors, allowing its effects to be studied systematically. New experimental results regarding ion dynamics in the liquid and direct demonstration of ion feedback from the gas to the liquid are discussed in this paper. In addition, a novel technique to measure the drift velocity of argon ions is introduced along with preliminary results obtained in gas.

physics.ins-det↗

arXiv2018

Prospects for long-range reactor monitoring with gadolinium-loaded water-Cherenkov detectors

Antineutrino detectors are practical, non-intrusive tools capable of remotely monitoring the activity of nuclear reactors. Here we explore the sensitivity of the Super-Kamiokande water-Cherenkov detector, following gadolinium loading, to antineutrinos from a nuclear reactor complex at a distance of approximately 190 km. The livetimes required to observe the two currently operating cores in the reactor complex depend on the activity of other reactors in the vicinity, as well as on estimates of detection efficiency and background rates. Under reasonable assumptions, we find that gadolinium-loaded Super-Kamiokande could detect the flux of antineutrinos from both cores at the Takahama reactor complex at 95% confidence level in 50 (10) live days 95% (50%) of the time, or the flux from one core in 397 (73) live days, provided that each core is operating at nominal power.

physics.ins-det↗

arXiv2017

Exploring the hidden interior of the Earth with directional neutrino measurements

Roughly 40% of the Earth's total heat flow is powered by radioactive decays in the crust and mantle. Geo-neutrinos produced by these decays provide important clues about the origin, formation and thermal evolution of our planet, as well as the composition of its interior. Previous measurements of geo-neutrinos have all relied on the detection of inverse beta decay reactions, which are insensitive to the contribution from potassium and do not provide model-independent information about the spatial distribution of geo-neutrino sources within the Earth. Here we present a method for measuring previously unresolved components of Earth's radiogenic heating using neutrino-electron elastic scattering and low-background, direction-sensitive tracking detectors. We calculate the exposures needed to probe various contributions to the total geo-neutrino flux, specifically those associated to potassium, the mantle and the core. The measurements proposed here chart a course for pioneering exploration of the veiled inner workings of the Earth.

physics.geo-ph↗

arXiv2017

Measurement of the directional sensitivity of DMTPC detectors

The Dark Matter Time Projection Chamber (DMTPC) is a direction-sensitive detector designed to measure the direction of recoiling $^{19}$F and $^{12}$C nuclei in low-pressure CF$_4$ gas using optical and charge readout systems. In this paper, we employ measurements from two DMTPC detectors, with operating pressures of 30-60 torr, to develop and validate a model of the directional response and performance of such detectors as a function of recoil energy. Using our model as a benchmark, we formulate the necessary specifications for a scalable directional detector with sensitivity comparable to that of current-generation counting (non-directional) experiments, which measure only recoil energy. Assuming the performance of existing DMTPC detectors, as well as current limits on the spin-dependent WIMP-nucleus cross section, we find that a 10-20 kg scale direction-sensitive detector is capable of correlating the measured direction of nuclear recoils with the predicted direction of incident dark matter particles and providing decisive (3$σ$) confirmation that a candidate signal from a non-directional experiment was indeed induced by elastic scattering of dark matter particles off of target nuclei.

astro-ph.IM↗

arXiv2012

Minimum Bias and Underlying Event Measurements with ATLAS

A summary of some of the recent minimum bias and underlying event measurements by the ATLAS collaboration is given. The results of several analyses using low-luminosity proton-proton collision data from the LHC taken at center-of-mass energies of sqrt(s) = 0.9, 2.36 and 7 TeV are presented. Data are compared to predictions by several different Monte Carlo event generators. The measurements expose limitations of the phenomenological models in properly describing the measured observables in all regions of phase space.

hep-ex↗