191 research outputs found
Ionization signals from electrons and alpha-particles in mixtures of liquid Argon and Nitrogen - perspectives on protons for Gamma Resonant Nuclear Absorption applications
In this paper we report on a detailed study of ionization signals produced by
Compton electrons and alpha-particles in a Time Projection Chamber (TPC) flled
with different mixtures of liquid Argon and Nitrogen. The measurements were
carried out with Nitrogen concentrations up to 15% and a drift electric feld in
the range 0-50 kV/cm. A prediction for proton ionization signals is made by
means of interpolation. This study has been conducted in view of the possible
use of liquid Ar-N2 TPCs for the detection of gamma-rays in the resonant band
of the Nitrogen absorption spectrum, a promising technology for security and
medical applications
30 kV coaxial vacuum-tight feedthrough for operation at cryogenic temperatures
In this paper we describe the technology of building a vacuum-tight high
voltage feedthrough which is able to operate at voltages up to 30 kV. The
feedthrough has a coaxial structure with a grounded sheath which makes it
capable to lead high voltage potentials into cryogenic liquids, without risk of
surface discharges in the gas phase above the liquid level. The feedthrough is
designed to be used in ionization detectors, based on liquefied noble gases,
such as Argon or Xenon
User guide to experimental auctions of vegetatively propagated seed. RTB User Guide
Experimental auctions are used to understand the value of different products to consumers through
estimations of willingness to pay (WTP). This information is valuable for many reasons, from obtaining local
prices attached to seed traits to informing seed businesses about acceptable production costs. Experimental
auctions do a better job of estimating this than simple questionnaires or surveys. By engaging participants
actively, experimental auctions lead to real or hypothetical consequences that make people think and act
carefully according to their personal preferences. This user guide provides an overview of different types of
experimental auctions and their use in seed system research. The guide discusses the structure of auctions,
planning and conducting them, and lessons from the field. Reading this guide will help you to be prepared to
design and implement an auction in your own project or intervention
Search for nucleon decays with EXO-200
A search for instability of nucleons bound in Xe nuclei is reported
with 223 kgyr exposure of Xe in the EXO-200 experiment. Lifetime
limits of 3.3 and 1.9 yrs are established for
nucleon decay to Sb and Te, respectively. These are the most
stringent to date, exceeding the prior decay limits by a factor of 9 and 7,
respectively
Deep Neural Networks for Energy and Position Reconstruction in EXO-200
We apply deep neural networks (DNN) to data from the EXO-200 experiment. In
the studied cases, the DNN is able to reconstruct the relevant parameters -
total energy and position - directly from raw digitized waveforms, with minimal
exceptions. For the first time, the developed algorithms are evaluated on real
detector calibration data. The accuracy of reconstruction either reaches or
exceeds what was achieved by the conventional approaches developed by EXO-200
over the course of the experiment. Most existing DNN approaches to event
reconstruction and classification in particle physics are trained on Monte
Carlo simulated events. Such algorithms are inherently limited by the accuracy
of the simulation. We describe a unique approach that, in an experiment such as
EXO-200, allows to successfully perform certain reconstruction and analysis
tasks by training the network on waveforms from experimental data, either
reducing or eliminating the reliance on the Monte Carlo.Comment: Accepted version. 33 pages, 28 figure
Investigation of radioactivity-induced backgrounds in EXO-200
The search for neutrinoless double-beta decay (0{\nu}{\beta}{\beta}) requires
extremely low background and a good understanding of their sources and their
influence on the rate in the region of parameter space relevant to the
0{\nu}{\beta}{\beta} signal. We report on studies of various {\beta}- and
{\gamma}-backgrounds in the liquid- xenon-based EXO-200 0{\nu}{\beta}{\beta}
experiment. With this work we try to better understand the location and
strength of specific background sources and compare the conclusions to
radioassay results taken before and during detector construction. Finally, we
discuss the implications of these studies for EXO-200 as well as for the
next-generation, tonne-scale nEXO detector.Comment: 9 pages, 7 figures, 3 table
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