103 research outputs found
Measurement of the scintillation resolution in liquid xenon and its impact for future segmented calorimeters
We report on a new measurement of the energy resolution that can be attained
in liquid xenon when recording only the scintillation light. Our setup is
optimised to maximise light collection, and uses state-of-the-art, high-PDE,
VUV-sensitive silicon photomultipliers. We find a value of 2.7% +- 0.3% FWHM at
511 keV, a result much better than previous measurements and very close to the
Poissonian resolution that we expect in our setup (3.0% +- 0.7% FWHM at 511
keV). Our results are compatible with a null value of the intrinsic energy
resolution in xenon, with an upper bound of 1.5% FWHM at 95% CL at 511 keV, to
be compared with 3--4% FWHM in the same region found by theoretical estimations
which have been standing for the last twenty years. Our work opens new
possibilities for apparatus based on liquid xenon and using scintillation only.
In particular it suggests that modular scintillation detectors using liquid
xenon can be very competitive as building blocks in segmented calorimeters,
with applications to nuclear and particle physics as well as Positron Emission
Tomography technology
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
Recommended from our members
Demonstration of the event identification capabilities of the NEXT-White detector
In experiments searching for neutrinoless double-beta decay, the possibility of identifying the two emitted electrons is a powerful tool in rejecting background events and therefore improving the overall sensitivity of the experiment. In this paper we present the first measurement of the efficiency of a cut based on the different event signatures of double and single electron tracks, using the data of the NEXT-White detector, the first detector of the NEXT experiment operating underground. Using a 228Th calibration source to produce signal-like and background-like events with energies near 1.6 MeV, a signal efficiency of 71.6 ± 1.5 stat± 0.3 sys% for a background acceptance of 20.6 ± 0.4 stat± 0.3 sys% is found, in good agreement with Monte Carlo simulations. An extrapolation to the energy region of the neutrinoless double beta decay by means of Monte Carlo simulations is also carried out, and the results obtained show an improvement in background rejection over those obtained at lower energies. [Figure not available: see fulltext.
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