We report results on the long-term variation of the neutron counting rate at the Canfranc Underground Laboratory, of importance for several low-background experiments installed there, including ...rare-event searches. The measurement campaign was performed employing the High Efficiency Neutron Spectrometry Array (HENSA) mounted in Hall A and lasted 412 live days. The present study is the first long-term measurement of the neutron rate with sensitivity over a wide range of neutron energies (from thermal up to 0.1 GeV and beyond) performed in any underground laboratory so far. Data on the environmental variables inside the experimental hall (radon concentration, air temperature, air pressure and humidity) were also acquired during all the measurement campaign. We have investigated for the first time the evolution of the neutron rate for different energies of the neutrons and its correlation with the ambient variables.
We report on WIMP search results of the XENON100 experiment, combining three runs summing up to 477 live days from January 2010 to January 2014. Data from the first two runs were already published. A ...blind analysis was applied to the last run recorded between April 2013 and January 2014 prior to combining the results. The ultralow electromagnetic background of the experiment, ∼5×10−3 events/(keVee×kg×day)) before electronic recoil rejection, together with the increased exposure of 48 kg×yr, improves the sensitivity. A profile likelihood analysis using an energy range of (6.6–43.3) keVnr sets a limit on the elastic, spin-independent WIMP-nucleon scattering cross section for WIMP masses above 8 GeV/c2, with a minimum of 1.1×10−45 cm2 at 50 GeV/c2 and 90% confidence level. We also report updated constraints on the elastic, spin-dependent WIMP-nucleon cross sections obtained with the same data. We set upper limits on the WIMP-neutron (proton) cross section with a minimum of 2.0×10−40 cm2 (52×10−40 cm2) at a WIMP mass of 50 GeV/c2, at 90% confidence level.
Even mass neutron-rich niobium isotopes are among the principal contributors to the reactor antineutrino energy spectrum. They are also among the most challenging to measure due to the refractory ...nature of niobium, and because they exhibit isomeric states lying very close in energy. The β-intensity distributions of 100gs,100mNb and 102gs,102mNb β decays have been determined using the total absorption γ-ray spectroscopy technique. The measurements were performed at the upgraded Ion Guide Isotope Separator On-Line facility at the University of Jyväskylä. Here, the double Penning trap system JYFLTRAP was employed to disentangle the β decay of the isomeric states. The new data obtained in this challenging measurement have a large impact in antineutrino summation calculations. As a result, for the first time the discrepancy between the summation model and the reactor antineutrino measurements in the region of the shape distortion has been reduced.
We present results from the direct search for dark matter with the XENON100 detector, installed underground at the Laboratori Nazionali del Gran Sasso of INFN, Italy. XENON100 is a two-phase ...time-projection chamber with a 62 kg liquid xenon target. Interaction vertex reconstruction in three dimensions with millimeter precision allows the selection of only the innermost 48 kg as the ultralow background fiducial target. In 100.9 live days of data, acquired between January and June 2010, no evidence for dark matter is found. Three candidate events were observed in the signal region with an expected background of (1.8 ± 0.6) events. This leads to the most stringent limit on dark matter interactions today, excluding spin-independent elastic weakly interacting massive particle (WIMP) nucleon scattering cross sections above 7.0 × 10(-45) cm(2) for a WIMP mass of 50 GeV/c(2) at 90% confidence level.
A particle identification technique for large acceptance spectrometers Cappuzzello, F.; Cavallaro, M.; Cunsolo, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2010, Volume:
621, Issue:
1
Journal Article
Peer reviewed
A technique to identify the heavy ions produced in nuclear reactions is presented. It is based on the use of a hybrid detector, which measures the energy loss, the residual energy, the position and ...angle of the ions at the focal plane of a magnetic spectrometer. The key point is the use of a powerful algorithm for the reconstruction of the ion trajectory, which makes the technique reliable even with large acceptance optical devices. Experimental results with the MAGNEX spectrometer show a remarkable resolution of about 1/160 in the mass parameter.
The XENON100 dark matter experiment Aprile, E.; Arisaka, K.; Arneodo, F. ...
Astroparticle physics,
April 2012, 2012-4-00, 20120401, Volume:
35, Issue:
9
Journal Article
Peer reviewed
Open access
► XENON100 is currently one of the most sensitive experiments to detect WIMP dark matter. ► Detector design and active/passive shielding reduce the radioactive background level. ► The event vertex of ...an interaction is reconstructed with a few mm precision. ► All position dependent signal corrections are presented in the paper. ► An energy scale exploiting the light-charge anti-correlation leads to an energy resolution competitive with NaI(Tl) crystals.
The XENON100 dark matter experiment uses liquid xenon (LXe) in a time projection chamber (TPC) to search for xenon nuclear recoils resulting from the scattering of dark matter Weakly Interacting Massive Particles (WIMPs). In this paper we present a detailed description of the detector design and present performance results, as established during the commissioning phase and during the first science runs.
The active target of XENON100 contains 62kg of LXe, surrounded by an LXe veto of 99kg, both instrumented with photomultiplier tubes (PMTs) operating inside the liquid or in xenon gas. The LXe target and veto are contained in a low-radioactivity stainless steel vessel, embedded in a passive radiation shield and is installed underground at the Laboratori Nazionali del Gran Sasso (LNGS), Italy. The experiment has recently published results from a 100 live-days dark matter search. The ultimate design goal of XENON100 is to achieve a spin-independent WIMP-nucleon scattering cross section sensitivity of σ=2×10−45cm2 for a 100GeV/c2 WIMP.
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