XXth International Conference on Neutrino Physics and Astrophysics

Poster Abstract


Searching for Annual Modulation in the WIMP Signal: The ANAIS Experiment at Canfranc

ANAIS (Annual Modulation with NaI's) is a large mass experiment intended to investigate seasonal modulation effects in the signal of galactic WIMPs using up to 10 NaI(Tl) hexagonal crystals (10.7 kg each) in the Canfranc Underground Laboratory (2450 m.w.e). A prototype is being developed in order to achieve the best performances of background and energy threshold before the installation of the complete set. The first version of the ANAIS prototype consist of one single crystal in a stainless steel enclosure coupled to a low background photomultiplier. Rejection of the thermoionic noise by means of pulse shape discrimination and reduction of the energy threshold have been efficiently achieved. Results corresponding to an exposure of 2069.85 kg.d with a ~4 keV energy threshold and a background level of ~1.2 c/(keV.kg.d) up to 10 keV are presented. New improvements such as the implementation of two ultra-low background photomultipliers and the removal of the stainless steel vessel are being developed. A monitoring system for the control of radon, the N2 flux injected inside the shielding and the temperatures in the laboratory and in the inner enceinte has been installed. The stability of the detector response (counting rates, resolution, energy calibration, pulse shape parameters, ...) has been tested through the continuous data taking of the prototype along more than 10 months.

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