Search

ANAIS is a direct dark matter detection experiment aiming at the confirmation or refutation of the DAMA/LIBRA positive annual modulation signal in the low energy detection rate, using the same target and technique. ANAIS-112, located at the Canfranc Underground Laboratory in Spain, is operating an array of 3$\times$3 ultrapure NaI(Tl) crystals with a total mass of 112.5 kg since August 2017. The trigger rate in the region of interest (1-6 keV) is dominated by non-bulk scintillation events. In order to discriminate these noise events from bulk scintillation events, robust filtering protocols have been developed. Although this filtering procedure works very well above 2 keV, the measured rate from 1 to 2 keV is about 50% higher than expected according to our background model, and we cannot discard non-bulk scintillation events as responsible of that excess. In order to improve the rejection of noise events, a Boosted Decision Tree has been developed and applied. With this new PMT-related noise rejection algorithm, the ANAIS-112 background between 1 and 2 keV is reduced by almost 30%, leading to an increase in sensitivity to the annual modulation signal. The reanalysis of the three years of ANAIS-112 data with this technique is also presented., Comment: Contributed to the TAUP2021 Conference, August 2021. To be published in Journal of Physics: Conference Series

The HENSA/ANAIS collaboration aims for the precise determination of the neutron flux that could affect ANAIS-112, an experiment looking for the dark matter annual modulation using NaI(Tl) scintillators. In this work, the first measurements of the neutron flux and Monte Carlo simulations of the neutron spectrum are reported.

ANAIS (Annual modulation with Nal Scintillators) is a dark matter direct detection experiment located at the Canfranc Underground Laboratory (LSC), in Spain. The goal is to confirm or refute in a model independent way the DAMA/LIBRA positive result: an annual modulation in the low-energy detection rate compatible with the expected signal induced by dark matter particles in the galactic halo. This signal, observed for about 20 years, is in strong tension with the negative results of other very sensitive experiments, but a direct comparison using the same target material, NaI(Tl), was still lacking. ANAIS-112, consisting of 112.5 kg of NaI(Tl) scintillators, is taking data at the LSC since August 2017. Here we present the preliminary annual modulation analysis corresponding to two years of data (exposure of 220.69 kgy) and the ANAIS-112 projected sensitivity for the scheduled 5 y of operation.

The annual modulation measured by the DAMA/LIBRA experiment can be explained by the interaction of dark matter WIMPs in NaI(Tl) scintillator detectors. Other experiments, with different targets or techniques, exclude the region of parameters singled out by DAMA/LIBRA, but the comparison of their results relies on several hypotheses regarding the dark matter model. ANAIS-112 is a dark matter search with 112.5 kg of NaI(Tl) scintillators under commissioning at the Canfranc Underground Laboratory (LSC) to test the DAMA/LIBRA result in a model independent way. We analyze its prospects in terms of the a priori critical and detection limits of the experiment. The analysis is based on the detector response and the background level measured for the first modules operated in Canfranc.

Cosmogenic activation is the most common source of radioactivity in copper, being 60 Co the most significant because of its long half-life (5.27 y) and saturation activity at sea level of 1 mBq/kg. Copper bricks, which had been exposed to cosmic rays for 41 days after their casting, were used to replace the internal 10 cm of the lead shielding of a HPGe detector placed at the Canfranc Underground Laboratory. We describe the outcome of the new shielding and the cosmogenic and primordial radioisotopes observed.

EURECA (European Underground Rare Event Calorimeter Array) is an astro-particle physics facility aiming to directly detect galactic dark matter. The Laboratoire Souterrain de Modane has been selected as host laboratory. The EURECA collaboration unites CRESST, EDELWEISS and the Spanish-French experiment ROSEBUD, thus concentrating and focussing effort on cryogenic detector research in Europe into a single facility. EURECA will use a target mass of up to one ton, enough to explore WIMP - nucleon scalar scattering cross sections in the region of 10 - 10 picobarn. A major advantage of EURECA is the planned use of more than just one target material (multi target experiment for WIMP identification). © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.

The production of radioactive isotopes in materials due to exposure to cosmic rays can become an hazard for experiments demanding ultra-low background conditions. Generation of long-lived products by cosmic nucleons at sea level has been studied for detector materials like germanium and tellurium and for other materials commonly used like copper; the main results will be summarized, considering both measurements and calculations. The isotope production cross sections and the cosmic ray spectrum are the two main ingredients when calculating this cosmogenic activation; the different alternatives for implementing them will be discussed. But cosmogenic activation can take place also deep underground due to cosmic muons, being relevant in this case the short-lived products. Studies carried out to evaluate the underground activation mainly for liquid scintillator materials will be commented too.