Analysis of the 40K contamination in NaI(Tl) crystals from different providers in the frame of the ANAIS project

Cuesta, Clara ; Amaré, Julio ; Cebrián, Susana (Universidad de Zaragoza) ; García, Eduardo (Universidad de Zaragoza) ; Ginestra, Carlos ; Martínez, María ; Oliván, Miguel A ; Ortigoza, Ysrael ; Ortíz de Solórzano, Alfonso (Universidad de Zaragoza) ; Pobes, Carlos ; Puimedón, Jorge (Universidad de Zaragoza) ; Sarsa, María Luisa ; Villar, José Ángel ; Villar, Patricia

Resumen: NaI(Tl) large crystals are applied in the search for galactic dark matter particles through their elastic scattering off the target nuclei in the detector by measuring the scintillation signal produced. However, energies deposited in the form of nuclear recoils are small, which added to the low efficiency to convert that energy into scintillation, makes that events at or very near the energy threshold, attributed either to radioactive backgrounds or to spurious noise (nonbulk NaI(Tl) scintillation events), can compromise the sensitivity goals of such an experiment. DAMA/LIBRA experiment, using 250 kg NaI(Tl) target, reported first evidence of the presence of an annual modulation in the detection rate compatible with that expected for a dark matter signal just in the region below 6 keVee (electron equivalent energy). 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 understand the origin of events at very low energy in large sodium iodide detectors and develop convenient filters to reject those nonattributable to scintillation in the bulk NaI(Tl) crystal. 40K is probably the most relevant radioactive contaminant in the bulk for NaI(Tl) detectors because of its important contribution to the background at very low energy. ANAIS goal is to achieve levels at or below 20 ppb natural potassium
In this paper we will report on our effort to determine the 40K contamination in several NaI(Tl) crystals, by measuring in coincidence between two (or more) of them. Results obtained for the 40K content of crystals from different providers will be compared and prospects of the ANAIS dark matter search experiment will be briefly reviewed

Idioma: Inglés

DOI: 10.1142/S0217751X14430106

Año: 2014

Publicado en: INTERNATIONAL JOURNAL OF MODERN PHYSICS A 29 (2014), 1443010 [17 pp]
ISSN: 0217-751X

Factor impacto JCR: 1.699 (2014)

Categ. JCR: PHYSICS, PARTICLES & FIELDS rank: 15 / 27 = 0.556 (2014) - Q3 - T2
Categ. JCR: PHYSICS, NUCLEAR rank: 12 / 21 = 0.571 (2014) - Q3 - T2

Financiación: info:eu-repo/grantAgreement/ES/MICINN/CPAN-CSD2007-00042
Financiación: info:eu-repo/grantAgreement/ES/MINECO/Consolider-Ingenio2010-MULTI-DARK-CSD2009-00064
Financiación: info:eu-repo/grantAgreement/ES/MINECO-FEDER/FPA2011-23749

Tipo y forma: Article (Published version)

Área (Departamento): Área Técnica. Lab. y Talleres (Dpto. Física Teórica)
Área (Departamento): Área Física Atóm.Molec.y Nucl. (Dpto. Física Teórica)