685 research outputs found
Recent resuts from DARKSIDE
DARKSIDE is a multi-stage program devoted to the direct detection of Dark Matter particles with a double phase liquid Argon Time Projection Chamber. Presently the DARKSIDE-50 detector is running underground at the
Laboratori Nazionali del Gran Sasso. It is placed inside a 30 t liquid organic scintillator sphere, acting as a neutron veto and hosted by a 10 kt water Cherenkov
detector. The DARKSIDE-50 setup with TPC filled with atmospheric argon is operating since November 2013 and we report here the first results of a Dark Matter search for a (1422 ± 67) kg×d truly background-free exposure. It can be translated into a 90% C.L. upper limit on the WIMP-nucleon cross section of 6.1×10−44 cm2, for a WIMP mass of 100 GeV/c2, being up to date the strongest limit obtained with
an argon target
Mitigation of Ar/K background for the GERDA Phase II experiment
Background coming from the Ar decay chain is considered to be one of
the most relevant for the GERDA experiment, which aims to search of the
neutrinoless double beta decay of Ge. The sensitivity strongly relies on
the absence of background around the Q-value of the decay. Background coming
from K, a progeny of Ar, can contribute to that background via
electrons from the continuous spectrum with an endpoint of 3.5 MeV. Research
and development on the suppression methods targeting this source of background
were performed at the low-background test facility LArGe. It was demonstrated
that by reducing K ion collection on the surfaces of the broad energy
germanium detectors in combination with pulse shape discrimination techniques
and an argon scintillation veto, it is possible to suppress the K
background by three orders of magnitude. This is sufficient for Phase II of the
GERDA experiment
Highly sensitive gamma-spectrometers of GERDA for material screening: Part I
The GERDA experiment aims to search for the neutrinoless double beta-decay of
76Ge and possibly for other rare processes. The sensitivity of the first phase
is envisioned to be more than one order of magnitude better than in previous
neutrinoless double beta-decay experiments. This implies that materials with
ultra-low radioactive contamination need to be used for the construction of the
detector and its shielding. Therefore the requirements on material screening
include high-sensitivity low-background detection techniques and long
measurement times. In this article, an overview of material-screening
laboratories available to the GERDA collaboration is given, with emphasis on
the gamma-spectrometry. Additionally, results of an intercomparison of the
evaluation accuracy in these laboratories are presented.Comment: Featured in: Proceedings of the XIV International Baksan School
"Particles and Cosmology" Baksan Valley, Kabardino-Balkaria, Russia, April
16-21,2007. INR RAS, Moscow 2008. ISBN 978-5-94274-055-9, pp. 228-232; (5
pages, 0 figures
Investigation of ASIC-based signal readout electronics for LEGEND-1000
LEGEND, the Large Enriched Germanium Experiment for Neutrinoless
Decay, is a ton-scale experimental program to search for neutrinoless double
beta () decay in the isotope Ge with an unprecedented
sensitivity. Building on the success of the low-background Ge-based
GERDA and MAJORANA DEMONSTRATOR experiments, the LEGEND collaboration is
targeting a signal discovery sensitivity beyond yr on the decay
half-life with approximately of exposure. Signal
readout electronics in close proximity to the detectors plays a major role in
maximizing the experiment's discovery sensitivity by reducing electronic noise
and improving pulse shape analysis capabilities for the rejection of
backgrounds. However, the proximity also poses unique challenges for the
radiopurity of the electronics. Application-specific integrated circuit (ASIC)
technology allows the implementation of the entire charge sensitive amplifier
(CSA) into a single low-mass chip while improving the electronic noise and
reducing the power consumption. In this work, we investigated the properties
and electronic performance of a commercially available ASIC CSA, the XGLab CUBE
preamplifier, together with a p-type point contact high-purity germanium
detector. We show that low noise levels and excellent energy resolutions can be
obtained with this readout. Moreover, we demonstrate the viability of pulse
shape discrimination techniques for reducing background events.Comment: 18 pages, 12 figures, 3 table
The DarkSide experiment: present status and future
DarkSideis a multi-stage program devoted to direct searches of Dark Matterparticles with detectors based on double phase liquid Argon Time Projection Chambe
A New 76Ge Double Beta Decay Experiment at LNGS
This Letter of Intent has been submitted to the Scientific Committee of the
INFN Laboratori Nazionali del Gran Sasso (LNGS) in March 2004. It describes a
novel facility at the LNGS to study the double beta decay of 76Ge using an
(optionally active) cryogenic fluid shield. The setup will allow to scrutinize
with high significance on a short time scale the current evidence for
neutrinoless double beta decay of 76Ge using the existing 76Ge diodes from the
previous Heidelberg-Moscow and IGEX experiments. An increase in the lifetime
limit can be achieved by adding more enriched detectors, remaining thereby
background-free up to a few 100 kg-years of exposure.Comment: 67 pages, 19 eps figures, 17 tables, gzipped tar fil
Search for electron antineutrino interactions with the Borexino Counting Test Facility at Gran Sasso
Electron antineutrino interactions above the inverse beta decay energy of
protons (E_\bar{\nu}_e>1.8) where looked for with the Borexino Counting Test
Facility (CTF). One candidate event survived after rejection of background,
which included muon-induced neutrons and random coincidences. An upper limit on
the solar flux, assumed having the B solar neutrino energy
spectrum, of 1.1 cm~s (90% C.L.) was set with a 7.8
ton year exposure. This upper limit corresponds to a solar neutrino
transition probability, , of 0.02 (90% C.L.).
Predictions for antineutrino detection with Borexino, including geoneutrinos,
are discussed on the basis of background measurements performed with the CTF.Comment: 10 pages, 9 figures, 5 table
Recent Borexino results and prospects for the near future
The Borexino experiment, located in the Gran Sasso National Laboratory, is an
organic liquid scintillator detector conceived for the real time spectroscopy
of low energy solar neutrinos. The data taking campaign phase I (2007 - 2010)
has allowed the first independent measurements of 7Be, 8B and pep fluxes as
well as the first measurement of anti-neutrinos from the earth. After a
purification of the scintillator, Borexino is now in phase II since 2011. We
review here the recent results achieved during 2013, concerning the seasonal
modulation in the 7Be signal, the study of cosmogenic backgrounds and the
updated measurement of geo-neutrinos. We also review the upcoming measurements
from phase II data (pp, pep, CNO) and the project SOX devoted to the study of
sterile neutrinos via the use of a 51Cr neutrino source and a 144Ce-144Pr
antineutrino source placed in close proximity of the active material.Comment: 8 pages, 11 figures. To be published as proceedings of Rencontres de
Moriond EW 201
Recommended from our members
Solar neutrino with Borexino: results and perspectives
Borexino is a unique detector able to perform measurement of solar neutrinos
fluxes in the energy region around 1 MeV or below due to its low level of
radioactive background. It was constructed at the LNGS underground laboratory
with a goal of solar Be neutrino flux measurement with 5\% precision. The
goal has been successfully achieved marking the end of the first stage of the
experiment. A number of other important measurements of solar neutrino fluxes
have been performed during the first stage. Recently the collaboration
conducted successful liquid scintillator repurification campaign aiming to
reduce main contaminants in the sub-MeV energy range. With the new levels of
radiopurity Borexino can improve existing and challenge a number of new
measurements including: improvement of the results on the Solar and terrestrial
neutrino fluxes measurements; measurement of pp and CNO solar neutrino fluxes;
search for non-standard interactions of neutrino; study of the neutrino
oscillations on the short baseline with an artificial neutrino source (search
for sterile neutrino) in context of SOX project.Comment: 15 pages, 4 figure
Low-energy (anti)neutrino physics with Borexino: Neutrinos from the primary proton-proton fusion process in the Sun
The Sun is fueled by a series of nuclear reactions that produce the energy
that makes it shine. The primary reaction is the fusion of two protons into a
deuteron, a positron and a neutrino. These neutrinos constitute the vast
majority of neutrinos reaching Earth, providing us with key information about
what goes on at the core of our star. Several experiments have now confirmed
the observation of neutrino oscillations by detecting neutrinos from secondary
nuclear processes in the Sun; this is the first direct spectral measurement of
the neutrinos from the keystone proton-proton fusion. This observation is a
crucial step towards the completion of the spectroscopy of pp-chain neutrinos,
as well as further validation of the LMA-MSW model of neutrino oscillations.Comment: Proceedings from NOW (Neutrino Oscillation Workshop) 201
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