From 22475ebbfc748f05caf4c12102c46648db7822d9 Mon Sep 17 00:00:00 2001
From: Lucia Morganti <lucia.morganti@cnaf.infn.it>
Date: Mon, 13 May 2019 09:32:27 +0200
Subject: [PATCH] Add new file for cupid
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+\documentclass[a4paper]{jpconf}
+\usepackage{graphicx}
+
+\bibliographystyle{iopart-num}
+%\usepackage{citesort}
+
+\begin{document}
+\title{CUPID-0 experiment}
+
+\author{CUPID-0 collaboration}
+
+%\address{}
+
+\ead{stefano.pirro@lngs.infn.it}
+
+\begin{abstract}
+With their excellent energy resolution, efficiency, and intrinsic radio-purity, cryogenic calorimeters are primed for the search of neutrino-less double beta decay (0$\nu$DBD).
+CUPID-0 is an array of 24 Zn$^{82}$Se scintillating bolometers used to search for 0$\nu$DBD of $^{82}$Se.
+It is the first large mass 0$\nu$DBD experiment exploiting a double read-out technique: the heat signal to accurately measure particle energies and the light signal to identify the particle type.
+The CUPID-0 is in data taking since March 2017 and obtained several outstanding scientific results.
+The configuration of the CUPID-0 data processing environment on the CNAF computing cluster has been used for the analysis of the first period of data taking.
+\end{abstract}
+
+\section{The experiment}
+Neutrino-less Double Beta Decay (0$\nu$DBD) is a hypothesized nuclear transition in which a nucleus decays emitting only two electrons.
+This process can not be accommodated in the Standard Model, as the absence of emitted neutrinos would violate the lepton number conservation.
+Among the several experimental approaches proposed for the search of 0$\nu$DBD, cryogenic calorimeters (bolometers) stand out for the possibility of achieving excellent energy resolution ($\sim$0.1\%), efficiency ($\ge$80\%) and intrinsic radio-purity. Moreover, the crystals that are operated as bolometers can be grown starting from most of the 0$\nu$DBD emitters, enabling the test of different nuclei.
+The state of the art of the bolometric technique is represented by CUORE, an experiment composed of 988 bolometers for a total mass of 741 kg, presently in data taking at Laboratori Nazionali del Gran Sasso.
+The ultimate limit of the CUORE background suppression resides in the presence of $\alpha$-decaying isotopes located in the detector structure.
+The CUPID-0 project \cite{Azzolini:2018dyb,Azzolini:2018tum} was born to overcome the actual limits.
+The main breakthrough of CUPID-0 is the addition of independent devices to measure the light signals emitted from scintillation in ZnSe bolometers.
+ The different properties of the light emission of electrons and $\alpha$ particles will enable event-by-event rejection of $\alpha$ interactions, suppressing the overall background in the region of interest for 0$\nu$DBD of at least one order of magnitude.
+The detector is composed by 26 ZnSe ultra-pure $\sim$ 500g bolometers, enriched at 95\% in $^{82}$Se, the 0$\nu$DBD emitter, and faced to Ge disks light detector operated as bolometers.
+CUPID-0 is hosted in a dilution refrigerator at the Laboratori Nazionali del Gran Sasso and started the data taking in March 2017.
+The first scientific run (i.e.,~ Phase I) ended in December 2018, collecting 9.95 kg$\times$y of ZnSe exposure.
+Such data were used to calculate a new limits on the $^{82}$Se 0$\nu$DBD~\cite{Azzolini:2018dyb,Azzolini:2018oph} and to develop a full background model of the experiment~\cite{Azzolini:2019nmi}.
+Phase II will start in June 2019 with an improved detector configuration.
+
+\section{CUPID-0 computing model and the role of CNAF}
+The CUPID-0 computing model is similar to the CUORE one, being the only difference in the sampling frequency and working point of the light detector bolometers.
+The full data stream is saved in root files, and a derivative trigger is software generated with a channel dependent threshold.
+%Raw data are saved in Root files and contain events in correspondence with energy releases occurred in the bolometers.
+Each event contains the waveform of the triggering bolometer and those geometrically close to it, plus some ancillary information.
+The non-event-based information is stored in a PostgreSQL database that is also accessed by the offline data analysis software.
+The data taking is arranged in runs, each run lasting about two days.
+Details of the CUPID-0 data acquisition and control system can be found in \cite{DiDomizio:2018ldc}.
+Raw data are transferred from the DAQ computers (LNGS) to the permanent storage area (located at CNAF) at the end of each run.
+A full copy of data is also preserved on tape.
+
+The data analysis flow consists of two steps; in the first level analysis, the event-based quantities are evaluated, while in the second level analysis the energy spectra are produced.
+The analysis software is organized in sequences.
+Each sequence consists of a collection of modules that scan the events in the Root files sequentially, evaluate some relevant quantities and store them back in the events.
+The analysis flow consists of several key steps that can be summarized in pulse amplitude estimation, detector gain correction, energy calibration and search for events in coincidence among multiple bolometers.
+The new tools developed for CUPID-0 to handle the light signals are introduced in \cite{Azzolini:2018yye,Beretta:2019bmm}.
+The main instance of the database was located at CNAF and the full analysis framework was used to analyze data until November 2017. A web page for offline reconstruction monitoring was maintained.
+%During 2017 a more intense usage of the CNAF resources is expected, both in terms of computing resourced and storage space.
+
+\section*{References}
+\bibliography{cupid-biblio}
+\end{document}
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