The neutrinoless double-beta decay background in TeO2 calorimetric searches receives two main contributions. One comes from α surface contamination and the other is mainly due to 2615 keV γ's, from the 232Th chain, scattering Compton with materials close to the detectors. In order to reduce the latter γ component, we propose to replace the usual copper holders with structures made of light organic compounds. A polymethylmethacrylate (PMMA) holder, containing small TeO2 crystals, is operated in a cryogenic setup, together with a similar assembly made of copper. The former registers a lower background in the Region of Interest (RoI), when exposed to a 232Th source, with a 3.8 σ significance. The background reduction of the setup is in agreement with Monte Carlo simulations at 1.2 σ. Then, a more realistic application is considered by simulating the inner CUORE experiment structure made of PMMA. We obtain a γ background reduction factor of 4.7+0.5−0.6 for photons coming from environmental sources and 5.0+0.1−0.2 for near detector contaminations with respect to the same setup made of copper.
Ghislandi, S., Biassoni, M., Nutini, I., Pozzi, S., Quitadamo, S. (2021). Organic compounds for rare events physics. IL NUOVO CIMENTO C, 44(2-3) [10.1393/ncc/i2021-21093-6].
Organic compounds for rare events physics
Biassoni M.;Nutini I.;Pozzi S.;
2021
Abstract
The neutrinoless double-beta decay background in TeO2 calorimetric searches receives two main contributions. One comes from α surface contamination and the other is mainly due to 2615 keV γ's, from the 232Th chain, scattering Compton with materials close to the detectors. In order to reduce the latter γ component, we propose to replace the usual copper holders with structures made of light organic compounds. A polymethylmethacrylate (PMMA) holder, containing small TeO2 crystals, is operated in a cryogenic setup, together with a similar assembly made of copper. The former registers a lower background in the Region of Interest (RoI), when exposed to a 232Th source, with a 3.8 σ significance. The background reduction of the setup is in agreement with Monte Carlo simulations at 1.2 σ. Then, a more realistic application is considered by simulating the inner CUORE experiment structure made of PMMA. We obtain a γ background reduction factor of 4.7+0.5−0.6 for photons coming from environmental sources and 5.0+0.1−0.2 for near detector contaminations with respect to the same setup made of copper.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.