Surface induced background in CUORE

Bolometers are very promising detectors for neutrinoless Double Beta Decay (0νDBD) searches because of their excellent energy resolution, the high detector efficiency and a wide choice of different materials used as absorber. In order to further improve the achievable sensitivity, many studies have been done in recent years in order to understand and thereby reduce the radioactive background. The current model of the background in the 0νDBD region assumes that it is mainly due to degraded α's from surface contamination of materials facing the crystals. This model is derived from the Cuoricino experience and it is mainly based on the study of coincident events between TeO2 bolometers since conventional techniques have not enough sensitivity to study the very low level of surface contaminations reached. In order to be able to identify the nature of the background observed in all the TeO2 bolometric tests and then confirm the background model, a very accurate measurement with BGO scintillating bolometers was performed. © 2012 Elsevier B.V. All rights reserved.