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En la enseñanza actual de la biología se nota una marcada deficiencia en lo referente a trabajos de campo. Este aspecto debe mejorarse, ya que la biología es una ciencia esencialmente experimental, tanto en el campo como en el laboratorio.El presente trabajo no es el reporte de una investigación científica, ya que el tiempo dedicado no puede ser en ninguna forma suficiente para llegar a conclusiones definitivas. Es sólo una actividad de entrenamiento y observación, que puede servir de modelo para trabajos de campo similares.

The background is the key issue of any experiment searching for the neutrinoless double beta decay (0 ν DBD) and one of the possible solutions is the use of high resolution detectors in which background can be actively discriminated. CUPID-0 is the first 0 ν DBD experiment based on scintillating bolometers able to perform efficient particle identification allowing for background reduction at the unprecedented level of ∼ 10−3 cts/(keV ⋅ kg ⋅ yr). This work makes an overview of the main problems and solutions applied in the construction of the CUPID-0 experimental apparatus, starting from the production of the crystal up to the assembly of the detector. Particular attention is payed to the methods applied to avoid the radio-contamination. The recovery of enriched Se loss along the crystal production cycle is discussed as the main challenge for the budget of this kind of experiments. The good bolometric performance of crystals is emphasized together with supplementary discrimination power offered in the case of ZnSe by the pulse shape analysis, besides the bare scintillation signal. We also make a brief report on detector performance and the results obtained till present which allowed us to establish the world best half-time limit on 82Se 0 ν DBD of >2.4 ⋅ 1024 yr (90% C.I.).

The CUPID-0 experiment searches for double beta decay using cryogenic calorimeters with double (heat and light) read-out. The detector, consisting of 24 ZnSe crystals 95 $$\%$$ enriched in $$^{82}$$ Se and two natural ZnSe crystals, started data-taking in 2017 at Laboratori Nazionali del Gran Sasso. We present the search for the neutrino-less double beta decay of $$^{82}$$ Se into the 0 $$_1^+$$ , 2 $$_1^+$$ and 2 $$_2^+$$ excited states of $$^{82}$$ Kr with an exposure of 5.74 kg $$\cdot $$ yr (2.24 $$\times $$ 10 $$^{25}$$ emitters $$\cdot $$ yr). We found no evidence of the decays and set the most stringent limits on the widths of these processes: $$\varGamma $$ ( $$^{82}$$ Se $$\rightarrow ^{82}$$ Kr $$_{0_1^+}$$ )8.55 $$\times $$ 10 $$^{-24}$$ yr $$^{-1}$$ , $$\varGamma $$ ( $$^{82}$$ Se $$\rightarrow ^{82}$$ Kr $$_{2_1^+}$$ ) $$\,{

International audience; Cryogenic calorimeters are currently used by experiments searching for neutrino-less double beta decay (0$\nu\beta\beta$). The sensitivity of these experiments is limited by the background coming from $\alpha$ radioactive contaminations. This background can be rejected exploiting the simultaneous read-out of light and heat in scintillating cryogenic calorimeters, because both the amplitude and the time development of the light signal depend on the nature of the particle interacting within. In this paper we present the CUPID-0 detector which represents the first demonstrator of this technique. Exploiting an array of 26 Zn$^{82}$Se scintillating crystals operated as calorimeters and monitored by 31 cryogenic light detectors, CUPID-0 demonstrated the capability to completely reject the $\alpha$ background, paving the way for a next generation experiment searching for 0$\nu\beta\beta$.

We report the result of the search for neutrinoless double beta decay of Se82 obtained with CUPID-0, the first large array of scintillating ZnSe82 cryogenic calorimeters implementing particle identification. We observe no signal in a 1.83 kg yr Se82 exposure, and we set the most stringent lower limit on the 0νββ Se82 half-life T1/20ν>2.4×1024 yr (90% credible interval), which corresponds to an effective Majorana neutrino mass mββ

The CUPID-0 detector hosted at the Laboratori Nazionali del Gran Sasso, Italy, is the first large array of enriched scintillating cryogenic detectors for the investigation of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{82}$$\end{document}82Se neutrinoless double-beta decay (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$0\nu \beta \beta $$\end{document}0νββ). CUPID-0 aims at measuring a background index in the region of interest (RoI) for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$0\nu \beta \beta $$\end{document}0νββ at the level of 10\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{-3}$$\end{document}-3 counts/(keV kg years), the lowest value ever measured using cryogenic detectors. CUPID-0 operates an array of Zn\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{82}$$\end{document}82Se scintillating bolometers coupled with bolometric light detectors, with a state of the art technology for background suppression and thorough protocols and procedures for the detector preparation and construction. In this paper, the different phases of the detector design and construction will be presented, from the material selection (for the absorber production) to the new and innovative detector structure. The successful construction of the detector lead to promising preliminary detector performance which is discussed here.

The CUPID-0 detector hosted at the Laboratori Nazionali del Gran Sasso, Italy, is the first large array of enriched scintillating cryogenic detectors for the investigation of $$^{82}$$ Se neutrinoless double-beta decay ( $$0\nu \beta \beta $$ ). CUPID-0 aims at measuring a background index in the region of interest (RoI) for $$0\nu \beta \beta $$ at the level of 10 $$^{-3}$$ counts/(keV kg years), the lowest value ever measured using cryogenic detectors. CUPID-0 operates an array of Zn $$^{82}$$ Se scintillating bolometers coupled with bolometric light detectors, with a state of the art technology for background suppression and thorough protocols and procedures for the detector preparation and construction. In this paper, the different phases of the detector design and construction will be presented, from the material selection (for the absorber production) to the new and innovative detector structure. The successful construction of the detector lead to promising preliminary detector performance which is discussed here.

The suppression of spurious events in the region of interest for neutrinoless double beta decay will play a major role in next generation experiments. The background of detectors based on the technology of cryogenic calorimeters is expected to be dominated by {\alpha} particles, that could be disentangled from double beta decay signals by exploiting the difference in the emission of the scintillation light. CUPID-0, an array of enriched Zn$^{82}$Se scintillating calorimeters, is the first large mass demonstrator of this technology. The detector started data-taking in 2017 at the Laboratori Nazionali del Gran Sasso with the aim of proving that dual read-out of light and heat allows for an efficient suppression of the {\alpha} background. In this paper we describe the software tools we developed for the analysis of scintillating calorimeters and we demonstrate that this technology allows to reach an unprecedented background for cryogenic calorimeters., Comment: 11 pages, 9 figures

International audience; With their excellent energy resolution, efficiency, and intrinsic radio-purity, cryogenic calorimeters are primed for the search of neutrino-less double beta decay (0nDBD). The sensitivity of these devices could be further increased by discriminating the dominant alpha background from the expected beta-like signal. The CUPID-0 collaboration aims at demonstrating that the measurement of the scintillation light produced by the absorber crystals allows for particle identification and, thus, for a complete rejection of the alpha background. The CUPID-0 detector, assembled in 2016 and now in data-taking, consists of 26 Zn$^{82}$ Se scintillating calorimeters for about $2 \times 10^{25}$ 0nDBD emitters. In this contribution we present the preliminary results obtained with the detector and the perspectives for a next generation project.

CUPID-0 is an array of 24 Zn82Se scintillating bolometers used to search for the 0νββ decay of 82Se. It is the first large mass 0νββ experiment exploiting a double read-out technique: the phonon signal to accurately measure particle energies and the light signal to reject the α-induced background. Its success might open the road to a next generation project of ton mass scale, CUPID. The array is in operation at Laboratori Nazionali del Gran Sasso since the beginning of 2017, in this paper we present the preliminary results obtained with an exposure of 10.45 kg• y.

LINAC VARIAN 2100 is where energetic electrons produce Bremsstrahlung radiation, with energies above the nucleon binding energy (E≈5.5MeV). This radiation induce (γ,n) and (e,e’n) reactions mainly in the natural tungsten target material (its total photoneutron cross section is about 4000 mb in a energy range from 9-17 MeV). These reactions may occur also in other components of the system (e.g. multi leaf collimator). During radiation treatment the human body may receive an additional dose inside and outside the treated volume produced by the mentioned nuclear reactions. We measured the neutron density at the treatment table using nuclear track detectors (PADC-NTD). These covered by a boron-converter are employed, including a cadmium filter, to determine the ratio between two groups of neutron energy, i.e. thermal and epithermal. The PADC-NTD detectors were exposed to the radiation field at the iso-center during regular operation of the accelerator. Neutron are determined indirectly by the converting reaction {sup 10}B(n,α){sup 7}Li the emerging charged particle leave their kinetic energy in the PADC forming a latent nuclear track, enlarged by chemical etching (6N, NaOH, 70°C). Track density provides information on the neutron density through calibration coefficient (∼1.6 10{sup 4} neutrons /track) obtained by a californium source. We report themore » estimation of the thermal and epithermal neutron field and its gradient for photoneutrons produced in radiotherapy treatments with 18 MV linear accelerators. It was obsered that photoneutron production have higher rate at the iso-center.« less