45 documents found, page 1 of 5
Avanços no projeto LouMu – Muografia para levantamentos geofísicos
Teixeira, Pedro; Blanco, Alberto; Caldeira, Bento; Tomé, Bernardo; Alexandre, Isabel; Matos, João; Silva, Jorge; Borges, José Fernando; Cazon, LorenzoO Projeto LouMu é uma colaboração em curso entre o Laboratório de Instrumentação e Física Experimental de Partículas, o Instituto de Ciências da Terra – Universidade de Évora e o Centro Ciência Viva do Lousal, contando ainda com o apoio do Laboratório Nacional de Energia e Geologia. O objetivo é explorar o potencial da técnica de muografia na Mina do Lousal, com a finalidade de criar as condições para a utiliza...
Muografia e a sua primeira aplicação em Portugal, na Mina do Lousal
Teixeira, Pedro; Blanco, Alberto; Caldeira, Bento; Tomé, Bernardo; Alexandre, Isabel; Matos, João; Silva, Jorge; Borges, José; Cazon, LorenzoA muografia é uma técnica de sondagem não invasiva que usa muões uma radiação natural de fundo com algum poder penetrante, para observar o interior das estruturas atravessadas. Com detetores adequados à observação da subsuperfície terrestre, é possível criar muografias, imagens com informação sobre a distribuição de densidades da região observada. Internacionalmente, esta técnica já foi aplicada em várias áreas...
An RPC-PET brain scanner demonstrator: first results
Fonte, Paulo; Lopes, Luís; Alves, Rui; Carolino, Nuno; Crespo, Paulo; Couceiro, Miguel; Cunha, Orlando; Dias, Nuno; Ferreira, Nuno C.; Fetal, SuseteWe present first results from a Positron Emission Tomography (PET) scanner demonstrator based on Resistive Plate Chambers and specialized for brain imaging. The device features a 30 cm wide cubic field-of-view and each detector comprises 40 gas gaps with 3D location of the interaction point of the photon. Besides other imagery, we show that the reconstructed image resolution, as evaluated by a hot-rod phantom, ...
Large-scale cosmic-ray anisotropies above 4 EeV measured by the Pierre Auger Ob...
Pierre Auger collaboration (376 authors); Abreu, Pedro; Andringa, Sofia; Assis, Pedro; Barreira Luz, Ricardo Jorge; Blanco, Alberto; Cazon, LorenzoWe present a detailed study of the large-scale anisotropies of cosmic rays with energies above 4 EeV measured using the Pierre Auger Observatory. For the energy bins [4,8] EeV and $E\geq 8$ EeV, the most significant signal is a dipolar modulation in right ascension at energies above 8 EeV, as previously reported. In this paper we further scrutinize the highest-energy bin by splitting it into three energy ranges...
An Indication of anisotropy in arrival directions of ultra-high-energy cosmic r...
Pierre Auger collaboration (392 authors); Abreu, Pedro; Andringa, Sofia; Assis, Pedro; Barreira Luz, Ricardo Jorge; Blanco, Alberto; Cazon, LorenzoA new analysis of the data set from the Pierre Auger Observatory provides evidence for anisotropy in the arrival directions of ultra-high-energy cosmic rays on an intermediate angular scale, which is indicative of excess arrivals from strong, nearby sources. The data consist of 5514 events above with zenith angles up to 80° recorded before 2017 April 30. Sky models have been created for two distinct populations...
Observation of inclined EeV air showers with the radio detector of the Pierre A...
Pierre Auger collaboration (394 authors); Abreu, Pedro; Andringa, Sofia; Assis, Pedro; Barreira Luz, Ricardo Jorge; Blanco, Alberto; Cazon, LorenzoWith the Auger Engineering Radio Array (AERA) of the Pierre Auger Observatory, we have observed the radio emission from 561 extensive air showers with zenith angles between 60o and 84o. In contrast to air showers with more vertical incidence, these inclined air showers illuminate large ground areas of several km2 with radio signals detectable in the 30 to 80 MHz band. A comparison of the measured radio-signal a...
Calibration of the logarithmic-periodic dipole antenna (LPDA) radio stations at...
Pierre Auger collaboration (404 authors); Abreu, Pedro; Andringa, Sofia; Assis, Pedro; Barreira Luz, Ricardo Jorge; Blanco, Alberto; Cazon, LorenzoAn in-situ calibration of a logarithmic periodic dipole antenna with a frequency coverage of 30 MHz to 80 MHz is performed. Such antennas are part of a radio station system used for detection of cosmic ray induced air showers at the Engineering Radio Array of the Pierre Auger Observatory, the so-called Auger Engineering Radio Array (AERA) . The directional and frequency characteristics of the broadband antenna ...
Autonomous RPCs for a Cosmic Ray ground array
Conceição, Ruben; Assis, Pedro; Blanco, Alberto; Carolino, Nuno; Cunha, Orlando; Dobrigkeit, Carola; Ferreira, Miguel; Fonte, Paulo; Lopes, LuisWe report on the behaviour of Resistive Plate Chambers (RPC) developed for muon detection in ultra-high energy cosmic ray (UHECR) experiments. The RPCs were developed for the MARTA project and were tested on field conditions. These RPCs cover an area of $1.5 \times 1.2\,{m^2}$ and are instrumented with 64 pickup electrodes providing a segmentation better than $20\,$cm. By shielding the detector units with enoug...
Inferences on mass composition and tests of hadronic interactions from 0.3 to 1...
Pierre Auger collaboration (405 authors); Abreu, Pedro; Andringa, Sofia; Assis, Pedro; Barreira Luz, Ricardo Jorge; Blanco, Alberto; Cazon, LorenzoWe present a new method for probing the hadronic interaction models at ultra-high energy and extracting details about mass composition. This is done using the time profiles of the signals recorded with the water-Cherenkov detectors of the Pierre Auger Observatory. The profiles arise from a mix of the muon and electromagnetic components of air-showers. Using the risetimes of the recorded signals we define a new ...
Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at...
Pierre Auger collaboration (402 authors); Abreu, Pedro; Andringa, Sofia; Assis, Pedro; Barreira Luz, Ricardo Jorge; Blanco, Alberto; Cazon, LorenzoWe report a multi-resolution search for anisotropies in the arrival directions of cosmic rays detected at the Pierre Auger Observatory with local zenith angles up to 80(o) and energies in excess of 4 EeV (4 × 10(18) eV). This search is conducted by measuring the angular power spectrum and performing a needlet wavelet analysis in two independent energy ranges. Both analyses are complementary since the angular po...