140 research outputs found
The -cleus experiment: A gram-scale fiducial-volume cryogenic detector for the first detection of coherent neutrino-nucleus scattering
We discuss a small-scale experiment, called -cleus, for the first
detection of coherent neutrino-nucleus scattering by probing nuclear-recoil
energies down to the 10 eV-regime. The detector consists of low-threshold
CaWO and AlO calorimeter arrays with a total mass of about 10 g and
several cryogenic veto detectors operated at millikelvin temperatures.
Realizing a fiducial volume and a multi-element target, the detector enables
active discrimination of , neutron and surface backgrounds. A first
prototype AlO device, operated above ground in a setup without
shielding, has achieved an energy threshold of eV and further
improvements are in reach. A sensitivity study for the detection of coherent
neutrino scattering at nuclear power plants shows a unique discovery potential
(5) within a measuring time of weeks. Furthermore, a site
at a thermal research reactor and the use of a radioactive neutrino source are
investigated. With this technology, real-time monitoring of nuclear power
plants is feasible.Comment: 14 pages, 19 figure
Detection of the Natural Alpha Decay of Tungsten
The natural alpha decay of 180W has been unambiguously detected for the first
time. The alpha peak is found in a (gamma,beta and neutron)-free background
spectrum. This has been achieved by the simultaneous measurement of phonon and
light signals with the CRESST cryogenic detectors. A half-life of T1/2 = (1.8
+- 0.2) x 10^18 y and an energy release of Q = (2516.4 +- 1.1 (stat.) +- 1.2
(sys.)) keV have been measured. New limits are also set on the half-lives of
the other naturally occurring tungsten isotopes.Comment: Submitted to Physical Review C Revised versio
Exploring CEvNS with NUCLEUS at the Chooz Nuclear Power Plant
Coherent elastic neutrino-nucleus scattering (CENS) offers a unique way
to study neutrino properties and to search for new physics beyond the Standard
Model. Nuclear reactors are promising sources to explore this process at low
energies since they deliver large fluxes of (anti-)neutrinos with typical
energies of a few MeV. In this paper, a new-generation experiment to study
CENS is described. The NUCLEUS experiment will use cryogenic detectors
which feature an unprecedentedly low energy threshold and a time response fast
enough to be operated in above-ground conditions. Both sensitivity to
low-energy nuclear recoils and a high event rate tolerance are stringent
requirements to measure CENS of reactor antineutrinos. A new experimental
site, denoted the Very-Near-Site (VNS) at the Chooz nuclear power plant in
France is described. The VNS is located between the two 4.25 GW
reactor cores and matches the requirements of NUCLEUS. First results of on-site
measurements of neutron and muon backgrounds, the expected dominant background
contributions, are given. In this paper a preliminary experimental setup with
dedicated active and passive background reduction techniques is presented.
Furthermore, the feasibility to operate the NUCLEUS detectors in coincidence
with an active muon-veto at shallow overburden is studied. The paper concludes
with a sensitivity study pointing out the promising physics potential of
NUCLEUS at the Chooz nuclear power plant
The CRESST Experiment: Recent Results and Prospects
The CRESST experiment seeks hypothetical WIMP particles that could account
for the bulk of dark matter in the Universe. The detectors are cryogenic
calorimeters in which WIMPs would scatter elastically on nuclei, releasing
phonons. The first phase of the experiment has successfully deployed several
262 g sapphire devices in the Gran Sasso underground laboratories. A main
source of background has been identified as microscopic mechanical fracturing
of the crystals, and has been eliminated, improving the background rate by up
to three orders of magnitude at low energies, leaving a rate close to one count
per day per kg and per keV above 10 keV recoil energy. This background now
appears to be dominated by radioactivity, and future CRESST scintillating
calorimeters which simultaneously measure light and phonons will allow
rejection of a great part of it.Comment: To appear in the proceedings of the CAPP2000 Conference, Verbier,
Switzerland, July, 2000 (eds J. Garcia-Bellido, R. Durrer, and M.
Shaposhnikov
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