Percorrer por autor "Conceição, R."
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- Long term experience in Autonomous Stations and production quality controlPublication . Lopes, L.; Alves, A.B.; Assis, P.; Blanco, A.; Carolino, N.; Cerda, M.A.; Conceição, R.; Cunha, O.; Dobrigkeit, C.; Ferreira, M.; Fonte, P.; de Almeida, L.; Luz, R.; Martins, V.B.; Mendes, L.; Nogueira, J.C.; Pereira, A.; Pimenta, M.; Sarmento, R.; de Souza, V.; Tomé, B.
- MARTA: a high-energy cosmic-ray detector concept for high-accuracy muon measurementPublication . Abreu, P. et al. (45 authors); Andringa, S.; Assis, P.; Blanco, A.; Brogueira, P; Carolino, N.; Cazon, L.; Conceição, R.; Cunha, O; Diogo, F.; Espadanal, J.; Ferreira, M.; Ferreira, P.; Fonte, P.; Gonçalves, P.; Lopes, L.; Mendes, L.; Pereira, A.; Pimenta, M.; Sarmento, R.; Tomé, B.; Wolters, H.A new concept for the direct measurement of muons in air showers is presented. The concept is based on resistive plate chambers (RPCs), which can directly measure muons with very good space and time resolution. The muon detector is shielded by placing it under another detector able to absorb and measure the electromagnetic component of the showers such as a water-Cherenkov detector, commonly used in air shower arrays. The combination of the two detectors in a single, compact detector unit provides a unique measurement that opens rich possibilities in the study of air showers.
- Multi-messenger Observations of a Binary Neutron Star MergerPublication . Pierre Auger and other collaborations (3541 authors); Mura, G.La; Abreu, P.; Andringa, S.; Assis, P.; Blanco, A.; Cazon, L.; Conceição, R.; Diogo, F.; Espadanal, J.; Lopes, L.; Pimenta, M.; Santos, E.; Sarmento, R.; Tomé, B.On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of $\sim 1.7\,{\rm{s}}$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg(2) at a luminosity distance of ${40}_{-8}^{+8}$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $\,{M}_{\odot }$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $\sim 40\,{\rm{Mpc}}$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position $\sim 9$ and $\sim 16$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.
- Muon counting using silicon photomultipliers in the AMIGA detector of the Pierre Auger observatoryPublication . Pierre Auger collaboration (422 authors); Abreu, P.; Andringa, S.; Assis, P.; Blanco, A.; Cazon, L.; Conceição, R.; Diogo, F.; Espadanal, J.; Lopes, L.; Pimenta, M.; Santos, E.; Sarmento, R.; Tomé, B.AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory designed to extend its energy range of detection and to directly measure the muon content of the cosmic ray primary particle showers. The array will be formed by an infill of surface water-Cherenkov detectors associated with buried scintillation counters employed for muon counting. Each counter is composed of three scintillation modules, with a 10 m(2) detection area per module. In this paper, a new generation of detectors, replacing the current multi-pixel photomultiplier tube (PMT) with silicon photo sensors (aka. SiPMs), is proposed. The selection of the new device and its front-end electronics is explained. A method to calibrate the counting system that ensures the performance of the detector is detailed. This method has the advantage of being able to be carried out in a remote place such as the one where the detectors are deployed. High efficiency results, i.e. 98% efficiency for the highest tested overvoltage, combined with a low probability of accidental counting (~2%), show a promising performance for this new system.
- Outdoor Field Experience with Autonomous RPC Based StationsPublication . Lopes, L.; Assis, P.; Blanco, A.; Carolino, N.; Cerda, M.A.; Conceição, R.; Cunha, O.; Ferreira, M.; Fonte, P.; Luz, R.; Mendes, L.; Pereira, A.; Pimenta, M.; Sarmento, R.; Tomé, B.In the last two decades Resistive Plate Chambers were employed in the Cosmic Ray Experiments COVER-PLASTEX and ARGO/YBJ. In both experiments the detectors were housed indoors, likely owing to gas distribution requirements and the need to control environment variables that directly affect RPCs operational stability. But in experiments where Extended Air Shower (EAS) sampling is necessary, large area arrays composed by dispersed stations are deployed, rendering this kind of approach impossible. In this situation, it would be mandatory to have detectors that could be deployed in small standalone stations, with very rare opportunities for maintenance, and with good resilience to environmental conditions. Aiming to meet these requirements, we started some years ago the development of RPCs for Autonomous Stations. The results from indoor tests and measurements were very promising, both concerning performance and stability under very low gas flow rate, which is the main requirement for Autonomous Stations. In this work we update the indoor results and show the first ones concerning outdoor stable operation. In particular, a dynamic adjustment of the high voltage is applied to keep gas gain constant.
- Search for High-energy Neutrinos from Binary Neutron Star Merger GW170817 with ANTARES, IceCube, and the Pierre Auger ObservatoryPublication . ANTARES, IceCube, Pierre Auger, LIGO Scientific, Virgo collaboration (1941 authors); Abreu, P.; Andringa, S.; Assis, P.; Blanco, A.; Cazon, L.; Conceição, R.; Diogo, F.; Espadanal, J.; Lopes, L.; Pimenta, M.; Santos, E.; Sarmento, R.; Tomé, B.The Advanced LIGO and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short gamma-ray burst (GRB) that followed the merger of this binary was also recorded by the Fermi Gamma-ray Burst Monitor (Fermi-GBM), and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), indicating particle acceleration by the source. The precise location of the event was determined by optical detections of emission following the merger. We searched for high-energy neutrinos from the merger in the GeV–EeV energy range using the Antares, IceCube, and Pierre Auger Observatories. No neutrinos directionally coincident with the source were detected within ±500 s around the merger time. Additionally, no MeV neutrino burst signal was detected coincident with the merger. We further carried out an extended search in the direction of the source for high-energy neutrinos within the 14 day period following the merger, but found no evidence of emission. We used these results to probe dissipation mechanisms in relativistic outflows driven by the binary neutron star merger. The non-detection is consistent with model predictions of short GRBs observed at a large off-axis angle.
- Sensitivity of EAS measurements to the energy spectrum of muonsPublication . Espadanal, J.; Cazon, L.; Conceição, R.We have studied how the energy spectrum of muons at production affects some of the most common measurements related to muons in extensive air shower studies, namely, the number of muons at the ground, the slope of the lateral distribution of muons, the apparent muon production depth, and the arrival time delay of muons at ground. We found that by changing the energy spectrum by an amount consistent with the difference between current models (namely EPOS-LHC and QGSJ et -II.04), the muon surface density at ground increases 5% at 20° zenith angle and 17% at 60° zenith angle. This effect introduces a zenith angle dependence on the reconstructed number of muons which might be experimentally observed. The maximum of the muon production depth distribution at 40° increases ∼ 10 g/cm 2 and ∼ 0 g/cm 2 at 60°, which, from pure geometrical considerations, increases the arrival time delay of muons. There is an extra contribution to the delay due to the subluminal velocities of muons of the order of ∼ 3 ns at all zenith angles. Finally, changes introduced in the logarithmic slope of the lateral density function are less than 2%.
- Studies on the response of a water-Cherenkov detector of the Pierre Auger Observatory to atmospheric muons using an RPC hodoscopePublication . Aab, A.; Abreu, P.; Aglietta, M.; Albury, J.M.; Allekotte, I.; Almela, A.; Castillo, J. Alvarez; Alvarez-Muñiz, J.; Batista, R. Alves; Anastasi, G.A.; Anchordoqui, L.; Ebr, J.; Engel, R.; Epicoco, I.; Erdmann, M.; Escobar, C.O.; Etchegoyen, A.; Falcke, H.; Farmer, J.; Farrar, G.; Fauth, A.C.; Andrada, B.; Fazzini, N.; Feldbusch, F.; Fenu, F.; Fick, B.; Figueira, J.M.; Filipčič, A.; Fodran, T.; Freire, M.M.; Fujii, T.; Fuster, A.; Andringa, S.; Galea, C.; Galelli, C.; García, B.; Vegas, A.L. Garcia; Gemmeke, H.; Gesualdi, F.; Gherghel-Lascu, A.; Ghia, P.L.; Giaccari, U.; Giammarchi, M.; Aramo, C.; Giller, M.; Glombitza, J.; Gobbi, F.; Gollan, F.; Golup, G.; Berisso, M. Gómez; Vitale, P.F. Gómez; Gongora, J.P.; González, N.; Goos, I.; Ferreira, P.R. Araújo; Góra, D.; Gorgi, A.; Gottowik, M.; Grubb, T.D.; Guarino, F.; Guedes, G.P.; Guido, E.; Hahn, S.; Halliday, R.; Hampel, M.R.; Asorey, H.; Hansen, P.; Harari, D.; Harvey, V.M.; Haungs, A.; Hebbeker, T.; Heck, D.; Hill, G.C.; Hojvat, C.; Hörandel, J.R.; Horvath, P.; Assis, P.; Hrabovský, M.; Huege, T.; Hulsman, J.; Insolia, A.; Isar, P.G.; Johnsen, J.A.; Jurysek, J.; Kääpä, A.; Kampert, K.H.; Keilhauer, B.; Avila, G.; Kemp, J.; Klages, H.O.; Kleifges, M.; Kleinfeller, J.; Köpke, M.; Mezek, G. Kukec; Lago, B.L.; LaHurd, D.; Lang, R.G.; de Oliveira, M.A. Leigui; Badescu, A.M.; Lenok, V.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Presti, D. Lo; Lopes, L.; López, R.; Lorek, R.; Luce, Q.; Lucero, A.; Payeras, A. Machado; Bakalova, A.; Malacari, M.; Mancarella, G.; Mandat, D.; Manning, B.C.; Manshanden, J.; Mantsch, P.; Marafico, S.; Mariazzi, A.G.; Mariş, I.C.; Marsella, G.; Balaceanu, A.; Martello, D.; Martinez, H.; Bravo, O. Martínez; Mastrodicasa, M.; Mathes, H.J.; Matthews, J.; Matthiae, G.; Mayotte, E.; Mazur, P.O.; Medina-Tanco, G.; Barbato, F.; Melo, D.; Menshikov, A.; Merenda, K.-D.; Michal, S.; Micheletti, M.I.; Miramonti, L.; Mockler, D.; Mollerach, S.; Montanet, F.; Morello, C.; Luz, R.J. Barreira; Mostafá, M.; Müller, A.L.; Muller, M.A.; Mulrey, K.; Mussa, R.; Muzio, M.; Namasaka, W.M.; Nellen, L.; Niculescu-Oglinzanu, M.; Niechciol, M.; Becker, K.H.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, L.; Nucita, A; Núñez, L.A.; Palatka, M.; Pallotta, J.; Panetta, M.P.; Papenbreer, P.; Bellido, J.A.; Parente, G.; Parra, A.; Pech, M.; Pedreira, F.; Pȩkala, J.; Pelayo, R.; Peña-Rodriguez, J.; Armand, J. Perez; Perlin, M.; Perrone, L.; Berat, C.; Peters, C.; Petrera, S.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino, M.; Pont, B.; Pothast, M.; Privitera, P.; Prouza, M.; Bertaina, M.E.; Puyleart, A.; Querchfeld, S.; Rautenberg, J.; Ravignani, D.; Reininghaus, M.; Ridky, J.; Riehn, F.; Risse, M.; Ristori, P.; Rizi, V.; Bertou, X.; de Carvalho, W. Rodrigues; Rojo, J. Rodriguez; Roncoroni, M.J.; Roth, M.; Roulet, E.; Rovero, A.C.; Ruehl, P.; Saffi, S.J.; Saftoiu, A.; Salamida, F.; Biermann, P.L.; Salazar, H.; Salina, G.; Gomez, J.D. Sanabria; Sánchez, F.; Santos, E.M.; Santos, E.; Sarazin, F.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Bister, T.; Savina, P.; Schäfer, C.M.; Scherini, V.; Schieler, H.; Schimassek, M.; Schimp, M.; Schlüter, F.; Schmidt, D.; Scholten, O.; Schovánek, P.; Biteau, J.; Schröder, F.G.; Schröder, S.; Sciutto, S.J.; Scornavacche, M.; Shellard, R.C.; Sigl, G.; Silli, G.; Sima, O.; Šmída, R.; Sommers, P.; Blanco, A.; Soriano, J.F.; Souchard, J.; Squartini, R.; Stadelmaier, M.; Stanca, D.; Stanič, S.; Stasielak, J.; Stassi, P.; Streich, A.; Suárez-Durán, M.; Blazek, J.; Sudholz, T.; Suomijärvi, T.; Supanitsky, A.D.; Šupík, J.; Szadkowski, Z.; Taboada, A.; Tapia, A.; Timmermans, C.; Tkachenko, O.; Tobiska, P.; Bleve, C.; Peixoto, C.J. Todero; Tomé, B.; Elipe, G. Torralba; Travaini, A.; Travnicek, P.; Trimarelli, C.; Trini, M.; Tueros, M.; Ulrich, R.; Unger, M.; Boháčová, M.; Urban, M.; Vaclavek, L.; Vacula, M.; Galicia, J.F. Valdés; Valiño, I.; Valore, L.; Vliet, A. van; Varela, E.; Cárdenas, B. Vargas; Vásquez-Ramírez, A.; Boncioli, D.; Veberič, D.; Ventura, C.; Quispe, I.D. Vergara; Verzi, V.; Vicha, J.; Villaseñor, L.; Vink, J.; Vorobiov, S.; Wahlberg, H.; Watson, A.A.; Bonifazi, C.; Weber, M.; Weindl, A.; Wiencke, L.; Wilczyński, H.; Winchen, T.; Wirtz, M.; Wittkowski, D.; Wundheiler, B.; Yushkov, A.; Zapparrata, O.; Arbeletche, L. Bonneau; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zehrer, L.; Zepeda, A.; Ziolkowski, M.; Zuccarello, F.; Borodai, N.; Botti, A.M.; Brack, J.; Bretz, T.; Briechle, F.L.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K.S.; Caccianiga, L.; Calcagni, L.; Cancio, A.; Canfora, F.; Caracas, I.; Carceller, J.M.; Caruso, R.; Castellina, A.; Catalani, F.; Cataldi, G.; Cazon, L.; Cerda, M.; Chinellato, J.A.; Choi, K.; Chudoba, J.; Chytka, L.; Clay, R.W.; Cerutti, A.C. Cobos; Colalillo, R.; Coleman, A.; Coluccia, M.R.; Conceição, R.; Condorelli, A.; Consolati, G.; Contreras, F.; Convenga, F.; Covault, C.E.; Dasso, S.; Daumiller, K.; Dawson, B.R.; Day, J.A.; de Almeida, R.M.; de Jesús, J.; de Jong, S.J.; Mauro, G. De; Neto, J.R.T. de Mello; Mitri, I. De; de Oliveira, J.; Franco, D. de Oliveira; de Souza, V.; Vito, E. De; Debatin, J.; Río, M. del; Deligny, O.; Dhital, N.; Matteo, A. Di; Castro, M.L. Díaz; Dobrigkeit, C.; D'Olivo, J.C.; Dorosti, Q.; Anjos, R.C. dos; Dova, M.T.
- The average longitudinal air shower profile: exploring the shape informationPublication . Conceição, R.; Andringa, S.; Diogo, F.; Pimenta, M.The shape of the extensive air shower (EAS) longitudinal profile contains information about the nature of the primary cosmic ray. However, with the current detection capabilities, the assessment of this quantity in an event-by-event basis is still very challenging. In this work we show that the average longitudinal profile can be used to characterise the average behaviour of high energy cosmic rays. Using the concept of universal shower profile it is possible to describe the shape of the average profile in terms of two variables, which can be already measured by the current experiments. These variables present sensitivity to both average primary mass composition and to hadronic interaction properties in shower development. We demonstrate that the shape of the average muon production depth profile can be explored in the same way as the electromagnetic profile having a higher power of discrimination for the state of the art hadronic interaction models. The combination of the shape variables of both profiles provides a new powerful test to the existing hadronic interaction models, and may also provide important hints about multi-particle production at the highest energies.