395 research outputs found
Geoneutrinos in Borexino
This paper describes the Borexino detector and the high-radiopurity studies
and tests that are integral part of the Borexino technology and development.
The application of Borexino to the detection and studies of geoneutrinos is
discussed.Comment: Conference: Neutrino Geophysics Honolulu, Hawaii December 14-16, 200
GNO Solar Neutrino Observations: Results for GNOI
We report the first GNO solar neutrino results for the measuring period GNOI,
solar exposure time May 20, 1998 till January 12, 2000. In the present
analysis, counting results for solar runs SR1 - SR19 were used till April 4,
2000. With counting completed for all but the last 3 runs (SR17 - SR19), the
GNO I result is [65.8 +10.2 -9.6 (stat.) +3.4 -3.6 (syst.)]SNU (1sigma) or
[65.8 + 10.7 -10.2 (incl. syst.)]SNU (1sigma) with errors combined. This may be
compared to the result for Gallex(I-IV), which is [77.5 +7.6 -7.8 (incl.
syst.)] SNU (1sigma). A combined result from both GNOI and Gallex(I-IV)
together is [74.1 + 6.7 -6.8 (incl. syst.)] SNU (1sigma).Comment: submitted to Physics Letters B, June 2000. PACS: 26.65. +t ; 14.60
Pq. Corresponding author: [email protected] ; [email protected]
A Cryogenic Underground Observatory for Rare Events: Cuore, an Update
CUORE is a proposed tightly packed array of 1000 TeO_{2} bolometers, each
being a cube 5 cm on a side with a mass of 750 gms. The array consists of 25
vertical towers, arranged in a square, of 5 towers by 5 towers, each containing
10 layers of 4 crystals. The design of the detector is optimized for ultralow-
background searches for neutrinoless double beta decay of ^{130}Te (33.8%
abundance), cold dark matter, solar axions, and rare nuclear decays. A
preliminary experiment involving 20 crystals of various sizes (MIBETA) has been
completed, and a single CUORE tower is being constructed as a smaller scale
experiment called CUORICINO. The expected performance and sensitivity, based on
Monte Carlo simulations and extrapolations of present results, are reported.Comment: in press: Nucl. Phys. of Russian Academy of Sc
A New Limit on the Neutrinoless DBD of 130Te
We report the present results of CUORICINO a cryogenic experiment on
neutrinoless double beta decay (DBD) of 130Te consisting of an array of 62
crystals of TeO2 with a total active mass of 40.7 kg. The array is framed
inside of a dilution refrigerator, heavily shielded against environmental
radioactivity and high-energy neutrons, and operated at a temperature of ~8 mK
in the Gran Sasso Underground Laboratory. Temperature pulses induced by
particle interacting in the crystals are recorded and measured by means of
Neutron Transmutation Doped thermistors. The gain of each bolometer is
stabilized with voltage pulses developed by a high stability pulse generator
across heater resistors put in thermal contact with the absorber.
The calibration is performed by means of two thoriated wires routinely
inserted in the set-up. No evidence for a peak indicating neutrinoless DBD of
130Te is detected and a 90% C.L. lower limit of 1.8E24 years is set for the
lifetime of this process. Taking largely into account the uncertainties in the
theoretical values of nuclear matrix elements, this implies an upper boud on
the effective mass of the electron neutrino ranging from 0.2 to 1.1 eV. This
sensitivity is similar to those of the 76Ge experiments.Comment: 4 pages, 2 figure
Complete results for five years of GNO solar neutrino observations
We report the complete GNO solar neutrino results for the measuring periods
GNO III, GNO II, and GNO I. The result for GNO III (last 15 solar runs) is
[54.3 + 9.9 - 9.3 (stat.)+- 2.3 (syst.)] SNU (1 sigma) or [54.3 + 10.2 - 9.6
(incl. syst.)] SNU (1 sigma) with errors combined. The GNO experiment is now
terminated after altogether 58 solar exposure runs that were performed between
May 20, 1998 and April 9, 2003. The combined result for GNO (I+II+III) is [62.9
+ 5.5 - 5.3 (stat.) +- 2.5 (syst.)] SNU (1 sigma) or [62.9 + 6.0 - 5.9] SNU (1
sigma) with errors combined in quadrature. Overall, gallium based solar
observations at LNGS (first in GALLEX, later in GNO) lasted from May 14, 1991
through April 9, 2003. The joint result from 123 runs in GNO and GALLEX is
[69.3 +- 5.5 (incl. syst.)] SNU (1 sigma). The distribution of the individual
run results is consistent with the hypothesis of a neutrino flux that is
constant in time. Implications from the data in particle- and astrophysics are
reiterated.Comment: 22 pages incl. 9 Figures and 8 Tables. to appear in: Physics Letters
B (accepted April 13, 2005) PACS: 26.65.+t ; 14.60.P
Double-beta decay of Te to the first 0 excited state of Xe with CUORICINO
The CUORICINO experiment was an array of 62 TeO single-crystal
bolometers with a total Te mass of kg. The experiment finished
in 2008 after more than 3 years of active operating time. Searches for both
and double-beta decay to the first excited state in
Xe were performed by studying different coincidence scenarios. The
analysis was based on data representing a total exposure of
N(Te)t=y. No evidence for a signal was
found. The resulting lower limits on the half lives are y (90% C.L.), and
y (90%
C.L.).Comment: 6 pages, 4 figure
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
Pulse-Shape discrimination with the Counting Test Facility
Pulse shape discrimination (PSD) is one of the most distinctive features of
liquid scintillators. Since the introduction of the scintillation techniques in
the field of particle detection, many studies have been carried out to
characterize intrinsic properties of the most common liquid scintillator
mixtures in this respect. Several application methods and algorithms able to
achieve optimum discrimination performances have been developed. However, the
vast majority of these studies have been performed on samples of small
dimensions. The Counting Test Facility, prototype of the solar neutrino
experiment Borexino, as a 4 ton spherical scintillation detector immersed in
1000 tons of shielding water, represents a unique opportunity to extend the
small-sample PSD studies to a large-volume setup. Specifically, in this work we
consider two different liquid scintillation mixtures employed in CTF,
illustrating for both the PSD characterization results obtained either with the
processing of the scintillation waveform through the optimum Gatti's method, or
via a more conventional approach based on the charge content of the
scintillation tail. The outcomes of this study, while interesting per se, are
also of paramount importance in view of the expected Borexino detector
performances, where PSD will be an essential tool in the framework of the
background rejection strategy needed to achieve the required sensitivity to the
solar neutrino signals.Comment: 39 pages, 17 figures, submitted to Nucl. Instr. Meth.
New results on solar neutrino fluxes from 192 days of Borexino data
We report the direct measurement of the ^7Be solar neutrino signal rate
performed with the Borexino detector at the Laboratori Nazionali del Gran
Sasso. The interaction rate of the 0.862 MeV ^7Be neutrinos is
49+-3(stat)+-4(syst) counts/(day * 100ton). The hypothesis of no oscillation
for ^7Be solar neutrinos is inconsistent with our measurement at the 4sigma
level. Our result is the first direct measurement of the survival probability
for solar nu_e in the transition region between matter-enhanced and
vacuum-driven oscillations. The measurement improves the experimental
determination of the flux of ^7Be, pp, and CNO solar nu_e, and the limit on the
magnetic moment of neutrinos
CUORE and beyond: bolometric techniques to explore inverted neutrino mass hierarchy
The CUORE (Cryogenic Underground Observatory for Rare Events) experiment will
search for neutrinoless double beta decay of Te. With 741 kg of TeO
crystals and an excellent energy resolution of 5 keV (0.2%) at the region of
interest, CUORE will be one of the most competitive neutrinoless double beta
decay experiments on the horizon. With five years of live time, CUORE projected
neutrinoless double beta decay half-life sensitivity is y
at ( y at the 90% confidence level), which
corresponds to an upper limit on the effective Majorana mass in the range
40--100 meV (50--130 meV). Further background rejection with auxiliary light
detector can significantly improve the search sensitivity and competitiveness
of bolometric detectors to fully explore the inverted neutrino mass hierarchy
with Te and possibly other double beta decay candidate nuclei.Comment: Submitted to the Proceedings of TAUP 2013 Conferenc
- …