Browsing by Author "Maio, A."
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- Current Status and Future Prospects of the SNO+ ExperimentPublication . SNO+ collaboration (156 authors); Andringa, S.; Barros, N.; Carvalho, J.; Chauhan, D.; Lozza, V.; Maio, A.; Maneira, J.; Prior, G.SNO+ is a large liquid scintillator-based experiment located 2km underground at SNOLAB, Sudbury, Canada. It reuses the Sudbury Neutrino Observatory detector, consisting of a 12m diameter acrylic vessel which will be filled with about 780 tonnes of ultra-pure liquid scintillator. Designed as a multipurpose neutrino experiment, the primary goal of SNO+ is a search for the neutrinoless double-beta decay (0$\nu\beta\beta$) of 130Te. In Phase I, the detector will be loaded with 0.3% natural tellurium, corresponding to nearly 800 kg of 130Te, with an expected effective Majorana neutrino mass sensitivity in the region of 55-133 meV, just above the inverted mass hierarchy. Recently, the possibility of deploying up to ten times more natural tellurium has been investigated, which would enable SNO+ to achieve sensitivity deep into the parameter space for the inverted neutrino mass hierarchy in the future. Additionally, SNO+ aims to measure reactor antineutrino oscillations, low-energy solar neutrinos, and geoneutrinos, to be sensitive to supernova neutrinos, and to search for exotic physics. A first phase with the detector filled with water will begin soon, with the scintillator phase expected to start after a few months of water data taking. The 0$\nu\beta\beta$ Phase I is foreseen for 2017.
- Mechanical construction and installation of the ATLAS tile calorimeterPublication . ATLAS Tile Calorimeter collaboration (234 authors); Alves, R.; Amaral, P.; Carvalho, J.; David, M.; Gomes, A.; Maio, A.; Marques, C.; Onofre, A.; Pereira, A.; Pina, J.; Pinhão, J.; Santos, J.; Saraiva, J.G.; Silva, J.This paper summarises the mechanical construction andinstallation of the Tile Calorimeter for the ATLASexperiment at the Large Hadron Collider in CERN, Switzerland. The TileCalorimeter is a sampling calorimeter using scintillator as the sensitivedetector and steel as the absorber and covers the central region of the ATLASexperiment up to pseudorapidities ±1.7. The mechanical construction ofthe Tile Calorimeter occurred over a periodof about 10 years beginning in 1995 with the completionof the Technical Design Report and ending in 2006 with the installationof the final module in the ATLAS cavern. Duringthis period approximately 2600 metric tons of steel were transformedinto a laminated structure to form the absorber of the sampling calorimeter.Following instrumentation and testing, which is described elsewhere, themodules were installed in the ATLAS cavern with a remarkable accuracy fora structure of this size and weight.
- The ALFA Roman Pot Detectors of ATLASPublication . Abdel Khalek, S. et al. (46 authors); Conde Muíño, P.; Gurriana, L.; Maio, A.; Maneira, M.J.P.; Palma, A.; Seabra, L.; Wemans, A.The ATLAS Roman Pot system is designed to determine the total proton-proton cross section as well as the luminosity at the Large Hadron Collider (LHC) by measuring elastic proton scattering at very small angles. The system is made of four Roman Pot stations, located in the LHC tunnel in a distance of about 240 m at both sides of the ATLAS interaction point. Each station is equipped with tracking detectors, inserted in Roman Pots which approach the LHC beams vertically. The tracking detectors consist of multi-layer scintillating fibre structures read out by Multi-Anode-Photo-Multipliers.
- The calibration system for the photomultiplier array of the SNO+ experimentPublication . SNO+ collaboration (23 authors); Alves, R.; Andringa, S.; Carvalho, J.; Chauhan, D.; Gurriana, L.; Maio, A.; Maneira, J.; Seabra, L.A light injection system using LEDs and optical fibres was designed for the calibration and monitoring of the photomultiplier array of the SNO+ experiment at SNOLAB. Large volume, non-segmented, low-background detectors for rare event physics, such as the multi-purpose SNO+ experiment, need a calibration system that allow an accurate and regular measurement of the performance parameters of their photomultiplier arrays, while minimising the risk of radioactivity ingress. The design implemented for SNO+ uses a set of optical fibres to inject light pulses from external LEDs into the detector. The design, fabrication and installation of this light injection system, as well as the first commissioning tests, are described in this paper. Monte Carlo simulations were compared with the commissioning test results, confirming that the system meets the performance requirements.
- The Laser calibration of the Atlas Tile Calorimeter during the LHC run 1Publication . ATLAS Tile Calorimeter system collaboration (238 authors); Santos, S.P.Amor Dos; Araque, J.P.; Castro, A.Blanco; Carvalho, J.; Castro, N.F.; De Sousa, M.J.Da Cunha Sargedas; Fiolhais, M.C.N.; Galhardo, B.; Gomes, A.; Jorge, P.M.; Martins, P.J.Magalhaes; Maio, A.; Maneira, J.; Seabra, L.F.Oleiro; Onofre, A.; Pedro, R.; Pina, J.; Santos, H.; Saraiva, J.G.; Silva, J.; Delgado, A.Tavares; Veloso, F.This article describes the Laser calibration system of the Atlas hadronic Tile Calorimeter that has been used during the run 1 of the LHC. First, the stability of the system associated readout electronics is studied. It is found to be stable with variations smaller than 0.6 %. Then, the method developed to compute the calibration constants, to correct for the variations of the gain of the calorimeter photomultipliers, is described. These constants were determined with a statistical uncertainty of 0.3 % and a systematic uncertainty of 0.2 % for the central part of the calorimeter and 0.5 % for the end-caps. Finally, the detection and correction of timing mis-configuration of the Tile Calorimeter using the Laser system are also presented.
- The LED and fiber based calibration system for the photomultiplier array of SNO+Publication . SNO+ collaboration (22 authors); Seabra, L.; Alves, R.; Andringa, S.; Carvalho, J.; Gurriana, L.; Maio, A.; Maneira, J.A new external LED/fiber light injection calibration system was designed for the calibration and monitoring of the photomultiplier array of the SNO+ experiment at SNOLAB. The goal of the calibration system is to allow an accurate and regular measurement of the photomultiplier array's performance, while minimizing the risk of radioactivity ingress. The choice in SNO+ was to use a set of optical fiber cables to convey into the detector the light pulses produced by external LEDs. The quality control was carried out using a modified test bench that was used in QC of optical fibers for TileCal/ATLAS. The optical fibers were characterized for transmission, timing and angular dispersions. This article describes the setups used for the characterization and quality control of the system based on LEDs and optical fibers and their results.