5 research outputs found
Dynamic instability transitions in 1D driven diffusive flow with nonlocal hopping
One-dimensional directed driven stochastic flow with competing nonlocal and
local hopping events has an instability threshold from a populated phase into
an empty-road (ER) phase. We implement this in the context of the asymmetric
exclusion process. The nonlocal skids promote strong clustering in the
stationary populated phase. Such clusters drive the dynamic phase transition
and determine its scaling properties. We numerically establish that the
instability transition into the ER phase is second order in the regime where
the entry point reservoir controls the current and first order in the regime
where the bulk is in control. The first order transition originates from a
turn-about of the cluster drift velocity. At the critical line, the current
remains analytic, the road density vanishes linearly, and fluctuations scale as
uncorrelated noise. A self-consistent cluster dynamics analysis explains why
these scaling properties remain that simple.Comment: 11 pages, 14 figures (25 eps files); revised as the publised versio
LEGEND-1000 Preconceptual Design Report
We propose the construction of LEGEND-1000, the ton-scale Large Enriched Germanium Experiment for Neutrinoless Decay. This international experiment is designed to answer one of the highest priority questions in fundamental physics. It consists of 1000 kg of Ge detectors enriched to more than 90% in the Ge isotope operated in a liquid argon active shield at a deep underground laboratory. By combining the lowest background levels with the best energy resolution in the field, LEGEND-1000 will perform a quasi-background-free search and can make an unambiguous discovery of neutrinoless double-beta decay with just a handful of counts at the decay value. The experiment is designed to probe this decay with a 99.7%-CL discovery sensitivity in the Ge half-life of years, corresponding to an effective Majorana mass upper limit in the range of 9-21 meV, to cover the inverted-ordering neutrino mass scale with 10 yr of live time
Spectral X-ray phase contrast imaging with a CdTe photon-counting detector
The present study focuses on the implementation of two X-ray phase contrast imaging (XPCI) techniques: free-space propagation (FSP) and single mask edge illumination (SM-EI) with a microfocus polychromatic X-ray source and a Timepix3 photon-counting detector with a CdTe sensor. This detector offers high spatial resolution, high detection efficiency and it is able to simultaneously record information about Time-over-Threshold (ToT) and Time-of-Arrival (ToA) for each X-ray photon. All these features play a key role in enabling an improvement of XPCI image quality, especially through spectral analysis, since it is possible to measure the energy of each incident X-ray photon. Measurements of phase contrast and contrast-to-noise ratio (CNR) are presented for different energy bins within the typical spectrum of soft X-ray imaging. It is shown that a significant enhancement of XPCI image quality can be obtained, for both implemented techniques, by performing pixel clustering to correct for charge sharing and by introducing some degree of energy-weighting