158 research outputs found
First presence of Macaca sylvanus at the late Early Pleistocene of Barranc de la Boella (La Mina locality, Francolí Basin, NE Iberia)
This research has been funded by Ministerio de Ciencia e Innovación, PID2021-122356NB-I00. D.F. is supported by the Ayuda del Programa de Formación de Profesorado Universitario (FPU20/03389) and is a Ph.D. student at the Programa de Doctorado en Biología at the Universidad Complutense de Madrid. A.E. is supported by H2020-MSCA-IF project No. 891529 (3DFOSSILDIET). A.P. is supported by the LATEUROPE project (Grant agreement ID 101052653) that has received funding from the European Research Council (ERC) under the European Union’s HORIZON1.1 research program. The Barranc de la Boella fieldwork is supported by the Ajuntament de la Canonja and Departament de Cultura of Generalitat de Catalunya (ARQ001SOL-186-2022). The Institut Català de Paleoecologia Humana i Evolució Social (IPHESCERCA) has received financial support from the Spanish Ministry of Science and Innovation through the ‘María de Maeztu’ program for Units of Excellence (CEX2019-000945-M).This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 89152
On the determination of the interaction time of GeV neutrinos in large argon gas TPCs
Next-generation megawatt-scale neutrino beams open the way to studying
neutrino-nucleus scattering resorting, for the first time, to gaseous targets.
This could lead to deeper knowledge of neutrino cross sections in the energy
region between hundreds of MeV and a few GeV, of interest for the upcoming
generation of long-baseline neutrino oscillation experiments. The challenge is,
therefore, to accurately track and (especially) time the particles produced in
neutrino interactions in large and seamless volumes down to few-MeV energies.
We propose to accomplish this through an optically-read time projection chamber
(TPC) filled with high-pressure argon and equipped with both tracking and
timing functions. In this work, we present a detailed study of the time-tagging
capabilities of such a device, based on end-to-end optical simulations that
include the effect of photon propagation, photosensor response, dark-count rate
and pulse reconstruction. We show that the neutrino interaction time could be
reconstructed from the primary-scintillation signal with a precision in the
range 1--2.5~ns () for point-like deposits with energies down to 5~MeV,
and well below 1~ns for minimum-ionizing particle tracks. A discussion on
previous limitations towards such a detection technology, and how they can be
realistically overcome in the near future thanks to recent developments in the
field, is presented (particularly the strong scintillation yields recently
reported for Ar/CF mixtures). The performance presented in our analysis
seems to be well within reach of next-generation neutrino-oscillation
experiments through the instrumentation of the proposed TPC with conventional
reflective materials and a SiPM carpet behind a transparent cathode
NEXT-100 Technical Design Report (TDR). Executive Summary
In this Technical Design Report (TDR) we describe the NEXT-100 detector that
will search for neutrinoless double beta decay (bbonu) in Xe-136 at the
Laboratorio Subterraneo de Canfranc (LSC), in Spain. The document formalizes
the design presented in our Conceptual Design Report (CDR): an
electroluminescence time projection chamber, with separate readout planes for
calorimetry and tracking, located, respectively, behind cathode and anode. The
detector is designed to hold a maximum of about 150 kg of xenon at 15 bar, or
100 kg at 10 bar. This option builds in the capability to increase the total
isotope mass by 50% while keeping the operating pressure at a manageable level.
The readout plane performing the energy measurement is composed of Hamamatsu
R11410-10 photomultipliers, specially designed for operation in low-background,
xenon-based detectors. Each individual PMT will be isolated from the gas by an
individual, pressure resistant enclosure and will be coupled to the sensitive
volume through a sapphire window. The tracking plane consists in an array of
Hamamatsu S10362-11-050P MPPCs used as tracking pixels. They will be arranged
in square boards holding 64 sensors (8 times8) with a 1-cm pitch. The inner
walls of the TPC, the sapphire windows and the boards holding the MPPCs will be
coated with tetraphenyl butadiene (TPB), a wavelength shifter, to improve the
light collection.Comment: 32 pages, 22 figures, 5 table
Evaluation of turbulent dissipation rate retrievals from Doppler Cloud Radar
Turbulent dissipation rate retrievals from cloud radar Doppler velocity measurements are evaluated using independent, in situ observations in Arctic stratocumulus clouds. In situ validation data sets of dissipation rate are derived using sonic anemometer measurements from a tethered balloon and high frequency pressure variation observations from a research aircraft, both flown in proximity to stationary, ground-based radars. Modest biases are found among the data sets in particularly low- or high-turbulence regimes, but in general the radar-retrieved values correspond well with the in situ measurements. Root mean square differences are typically a factor of 4-6 relative to any given magnitude of dissipation rate. These differences are no larger than those found when comparing dissipation rates computed from tetheredballoon and meteorological tower-mounted sonic anemometer measurements made at spatial distances of a few hundred meters. Temporal lag analyses suggest that approximately half of the observed differences are due to spatial sampling considerations, such that the anticipated radar-based retrieval uncertainty is on the order of a factor of 2-3. Moreover, radar retrievals are clearly able to capture the vertical dissipation rate structure observed by the in situ sensors, while offering substantially more information on the time variability of turbulence profiles. Together these evaluations indicate that radar-based retrievals can, at a minimum, be used to determine the vertical structure of turbulence in Arctic stratocumulus clouds
Radon and material radiopurity assessment for the NEXT double beta decay experiment
The Neutrino Experiment with a Xenon TPC (NEXT), intended to investigate the
neutrinoless double beta decay using a high-pressure xenon gas TPC filled with
Xe enriched in 136Xe at the Canfranc Underground Laboratory in Spain, requires
ultra-low background conditions demanding an exhaustive control of material
radiopurity and environmental radon levels. An extensive material screening
process is underway for several years based mainly on gamma-ray spectroscopy
using ultra-low background germanium detectors in Canfranc but also on mass
spectrometry techniques like GDMS and ICPMS. Components from shielding,
pressure vessel, electroluminescence and high voltage elements and energy and
tracking readout planes have been analyzed, helping in the final design of the
experiment and in the construction of the background model. The latest
measurements carried out will be presented and the implication on NEXT of their
results will be discussed. The commissioning of the NEW detector, as a first
step towards NEXT, has started in Canfranc; in-situ measurements of airborne
radon levels were taken there to optimize the system for radon mitigation and
will be shown too.Comment: Proceedings of the Low Radioactivity Techniques 2015 workshop
(LRT2015), Seattle, March 201
Measurement of radon-induced backgrounds in the NEXT double beta decay experiment
The measurement of the internal Rn activity in the NEXT-White
detector during the so-called Run-II period with Xe-depleted xenon is
discussed in detail, together with its implications for double beta decay
searches in NEXT. The activity is measured through the alpha production rate
induced in the fiducial volume by Rn and its alpha-emitting progeny.
The specific activity is measured to be ~mBq/m. Radon-induced electrons have also been
characterized from the decay of the Bi daughter ions plating out on the
cathode of the time projection chamber. From our studies, we conclude that
radon-induced backgrounds are sufficiently low to enable a successful NEXT-100
physics program, as the projected rate contribution should not exceed
0.1~counts/yr in the neutrinoless double beta decay sample.Comment: 28 pages, 10 figures, 6 tables. Version accepted for publication in
JHE
Sensitivity of a tonne-scale NEXT detector for neutrinoless double beta decay searches
The Neutrino Experiment with a Xenon TPC (NEXT) searches for the neutrinoless
double-beta decay of Xe-136 using high-pressure xenon gas TPCs with
electroluminescent amplification. A scaled-up version of this technology with
about 1 tonne of enriched xenon could reach in less than 5 years of operation a
sensitivity to the half-life of neutrinoless double-beta decay decay better
than 1E27 years, improving the current limits by at least one order of
magnitude. This prediction is based on a well-understood background model
dominated by radiogenic sources. The detector concept presented here represents
a first step on a compelling path towards sensitivity to the parameter space
defined by the inverted ordering of neutrino masses, and beyond.Comment: 22 pages, 11 figure
- …