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Cerdeno D.G.,Autonomous University of Madrid | Marcos C.,Autonomous University of Madrid | Peiro M.,Autonomous University of Madrid | Fornasa M.,University of Nottingham | And 15 more authors.
International Journal of Modern Physics A | Year: 2014

In the last decade direct detection Dark Matter (DM) experiments have increased enormously their sensitivity and ton-scale setups have been proposed, especially using germanium and xenon targets with double readout and background discrimination capabilities. In light of this situation, we study the prospects for determining the parameters of Weakly Interacting Massive Particle (WIMP) DM (mass, spin-dependent (SD) and spin-independent (SI) cross-section off nucleons) by combining the results of such experiments in the case of a hypothetical detection. In general, the degeneracy between the SD and SI components of the scattering cross-section can only be removed using targets with different sensitivities to these components. Scintillating bolometers, with particle discrimination capability, very good energy resolution and threshold and a wide choice of target materials, are an excellent tool for a multitarget complementary DM search. We investigate how the simultaneous use of scintillating targets with different SD-SI sensitivities and/or light isotopes (as the case of CaF2 and NaI) significantly improves the determination of the WIMP parameters. In order to make the analysis more realistic we include the effect of uncertainties in the halo model and in the spin-dependent nuclear structure functions, as well as the effect of a thermal quenching different from 1. © 2014 World Scientific Publishing Company.

Coron N.,University Paris - Sud | Cuesta C.,University of Zaragoza | Cuesta C.,Laboratorio Subterraneo Of Canfranc | Garcia E.,University of Zaragoza | And 24 more authors.
Astroparticle Physics | Year: 2013

NaI(Tl) is a widely-used scintillator at room temperature, and it is particularly interesting as a target for dark matter searches. Its hygroscopic character however makes it unsuitable for many applications, in particular for bolometric particle detection at very low temperature. Despite that, a NaI scintillating bolometer would provide unique features for dark matter detection, like β/γ background rejection through particle discrimination and thermal quenching factors for nuclear with respect to electron recoils close to one. With the long-term goal of developing a scintillating NaI bolometer, we have tested NaI(Tl) crystals coated by vapor-deposited poly-p-xylylene (parylene) and studied their optical and mechanical behavior in the mK range. We present X-ray excited scintillation spectra of a parylene-coated NaI(Tl) sample at 1.5, 4 and 77 K, and measurements of the light output as function of the temperature over the 1.5-300 K range. At 1.5 K the wavelength of maximum emission is observed at 325 nm. Thermoluminescence peaks are found at around 60, 95 and 150 K. Tests of mechanical and optical resistance to thermal cycles of 45 g parylene-coated NaI(Tl) cylinders are also presented, and the adequacy and effectiveness of this coating technique is discussed. © 2013 Elsevier B.V. All rights reserved.

Jordan D.,University of Valencia | Tain J.L.,University of Valencia | Algora A.,University of Valencia | Agramunt J.,University of Valencia | And 11 more authors.
Astroparticle Physics | Year: 2013

The energy distribution of the neutron background was measured for the first time at Hall A of the Canfranc Underground Laboratory. For this purpose we used a novel approach based on the combination of the information obtained with six large high-pressure 3He proportional counters embedded in individual polyethylene blocks of different size. In this way not only the integral value but also the flux distribution as a function of neutron energy was determined in the range from 1 eV to 10 MeV. This information is of importance because different underground experiments show different neutron background energy dependence. The high sensitivity of the setup allowed to measure a neutron flux level which is about four orders of magnitude smaller that the neutron background at sea level. The integral value obtained is ΦHall A=(3.44±0.35)×10-6 cm-2 s-1. © 2012 Elsevier B.V. All rights reserved.

Amare J.,Laboratorio Subterraneo Of Canfranc | Borjabad S.,Laboratorio Subterraneo Of Canfranc | Cebrian S.,University of Zaragoza | Cuesta C.,Laboratorio Subterraneo Of Canfranc | And 14 more authors.
Optical Materials | Year: 2014

Samples from different materials typically used as optical windows or light guides in scintillation detectors were studied in a very low background environment, at the Canfranc Underground Laboratory, searching for scintillation. A positive result can be confirmed for natural quartz: two distinct scintillation components have been identified, not being excited by an external gamma source. Although similar effect has not been observed neither for synthetic quartz nor for methacrylate, a fast light emission excited by intense gamma flux is evidenced for all the samples in our measurements. These results could affect the use of these materials in low energy applications of scintillation detectors requiring low radioactive background conditions, as they entail a source of background. © 2014 Elsevier B.V. All rights reserved.

Amare J.,University of Zaragoza | Amare J.,Laboratorio Subterraneo Of Canfranc | Cebrian S.,University of Zaragoza | Cebrian S.,Laboratorio Subterraneo Of Canfranc | And 25 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2014

The ANAIS (Annual Modulation with NaI(Tl) Scintillators) experiment aims at the confirmation of the DAMA/LIBRA signal using the same target and technique at the Canfranc Underground Laboratory. 250 kg of ultrapure NaI(Tl) crystals will be used as a target, divided into 20 modules, each coupled to two photomultipliers. Two NaI(Tl) crystals of 12.5 kg each, grown by Alpha Spectra from a powder having a potassium level under the limit of our analytical techniques, form the ANAIS-25 set-up. The background contributions are being carefully studied and preliminary results are presented: their natural potassium content in the bulk has been quantified, as well as the uranium and thorium radioactive chains presence in the bulk through the discrimination of the corresponding alpha events by PSA, and due to the fast commissioning, the contribution from cosmogenic activated isotopes is clearly identified and their decay observed along the first months of data taking. Following the procedures established with ANAIS-0 and previous prototypes, bulk NaI(Tl) scintillation events selection and light collection efficiency have been also studied in ANAIS-25.

Cebrian S.,University of Zaragoza | Cebrian S.,Laboratorio Subterraneo Of Canfranc
AIP Conference Proceedings | Year: 2013

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. © 2013 AIP Publishing LLC.

Cebrian S.,University of Zaragoza | Cebrian S.,Laboratorio Subterraneo Of Canfranc | Cuesta C.,University of Zaragoza | Cuesta C.,Laboratorio Subterraneo Of Canfranc | And 26 more authors.
Astroparticle Physics | Year: 2012

NaI (Tl) is a well known high light yield scintillator. Very large crystals can be grown to be used in a wide range of applications. In particular, such large crystals are very good-performing detectors in the search for dark matter, where they have been used for a long time and reported first evidence of the presence of an annual modulation in the detection rate, compatible with that expected for a dark matter signal. In the frame of the ANAIS (Annual modulation with NaI Scintillators) dark matter search project, a large and long effort has been carried out in order to characterize the background of sodium iodide crystals. In this paper we present in detail our background model for a 9.6 kg NaI (Tl) detector taking data at the Canfranc Underground Laboratory (LSC): most of the contaminations contributing to the background have been precisely identified and quantified by different complementary techniques such as HPGe spectrometry, discrimination of alpha particles vs. beta/gamma background by Pulse Shape Analysis (PSA) and coincidence techniques; then, Monte Carlo (MC) simulations using Geant4 package have been carried out for the different contributions. Only a few assumptions are required in order to explain most of the measured background at high energy, supporting the goodness of the proposed model for the present ANAIS prototype whose background is dominated by 40K bulk contamination. At low energy, some non-explained background components are still present and additional work is required to improve background understanding, but some plausible background sources contributing in this range have been studied in this work. Prospects of achievable backgrounds, at low and high energy, for the ANAIS-upgraded detectors, relying on the proposed background model conveniently scaled, are also presented. © 2012 Elsevier B.V. All rights reserved.

Bettini A.,Laboratorio Subterraneo Of Canfranc | Bettini A.,University of Padua | Bettini A.,National Institute of Nuclear Physics, Italy
Physics of the Dark Universe | Year: 2014

Deep underground laboratories provide the low radioactive background environment necessary to explore the highest energy scales that cannot be reached with accelerators, by searching for extremely rare phenomena. In addition, these laboratories provide unique opportunities to sectors of other fields: geodynamics, rock mechanics, hydrology and the study of life under extreme conditions. Underground laboratories of different size and depth exist in all the regions. This article is focussed on future perspectives, reviewing the newer facilities, those still under project and the space becoming available at the older laboratories. We shall not discuss the existing or proposed facilities dedicated to detectors of long base line experiment with reactor or accelerator beams. © 2014.

Bettini A.,Laboratorio Subterraneo Of Canfranc | Bettini A.,University of Padua
European Physical Journal Plus | Year: 2012

The Canfranc Underground Laboratory, presently the second largest in Europe, is located under the Mount Tobazo in the central Spanish Pyrenees, in the province of Huesca in Aragón. After recalling a few historical elements, I shall describe the LSC infrastructures and services both underground and the support ones on the surface. I shall then report the characterisation measurements done so far. A summary of the approved experiments and projects for the future will complete the article. © 2012, Società Italiana di Fisica and Springer-Verlag Berlin Heidelberg.

Bettini A.,University of Padua | Bettini A.,Laboratorio Subterraneo Of Canfranc
European Physical Journal Plus | Year: 2012

This paper is an introduction to a series of coordinated articles of an EPJ Plus Focus Point on underground physics laboratories, written by the directors of the larger ones and by the coordinators of the principal new projects. The paper is largely based on the text of my lecture Perspectives of underground physics, given at the Enrico Fermi Varenna International School, Course CLXXXII (2011), Neutrino physics and astrophysics, reproduced here by permission of the Italian Physical Society. Underground laboratories provide the low radioactive background environment necessary to explore the highest energy scales that cannot be reached with accelerators, by searching for extremely rare phenomena. Experiments range from the direct search of the dark-matter particles that constitute the largest fraction of matter in the Universe, to the exploration of the properties of the neutrinos, the most elusive of the known particles and which might be particle and antiparticle at the same time, to the investigation on why our universe contains only matter and almost no antimatter, and much more. © 2012, Società Italiana di Fisica and Springer-Verlag Berlin Heidelberg.

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