Browsing by Author "Cunha, Orlando"
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- Autonomous RPCs for a Cosmic Ray ground arrayPublication . Conceição, Ruben; Assis, Pedro; Blanco, Alberto; Carolino, Nuno; Cunha, Orlando; Dobrigkeit, Carola; Ferreira, Miguel; Fonte, Paulo; Lopes, Luis; Luz, Ricardo; Martins, Victor Barbosa; Mendes, Luis; Pereira, Américo; Pimenta, Mário; Sarmento, Raul; Shellard, Ronald; de Souza, Vitor; Tomé, BernardoWe 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 enough slant mass to absorb the electromagnetic component in the air showers, a clean measurement of the muon content is allowed, a concept to be implemented in a next generation of UHECR experiments. The operation of a ground array detector poses challenging demands, as the RPC must operate remotely under extreme environmental conditions, with limited budgets for power and minimal maintenance. The RPC, DAQ, High Voltage and monitoring systems are enclosed in an aluminium-sealed case, providing a compact and robust unit suited for outdoor environments, which can be easily deployed and connected. The RPCs developed at LIP-Coimbra are able to operate using a very low gas flux, which allows running them for few years with a small gas reservoir. Several prototypes have already been built and tested both in the laboratory and outdoors. We report on the most recent tests done in the field that show that the developed RPCs have operated in a stable way for more than 2 years in field conditions.
- Muon Array with RPCs for Tagging Air showers (MARTA)Publication . Sarmento, Raul et al. (42 authors); Abreu, Pedro; Andringa Dias, Sofia; Assis, Pedro; Castro, Alberto Blanco; Brogueira, Pedro; Carolino, N.; Cazon, Lorenzo; Cunha, Orlando; Diogo, Francisco; Espadanal, João; Ferreira, Miguel; Fonte, Paulo; Goncalves, Patricia; Lopes, Luis; Luz, Ricardo; Mendes, Luis; Pereira, A.; Pimenta, M.; Espirito Santo, Catarina; Tome, B.; Wolters, HelmutWe discuss the concept of an array with Resistive Plate Chambers (RPC) for muon detection in ultra-high energy cosmic ray (UHECR) experiments. RPC have been used in particle physics experiments due to their fast timing properties and spatial resolution. The operation of a ground array detector poses challenging demands, as the RPC must operate remotely under extreme en- vironments, with limited power and minimal maintenance. In its baseline configuration, each MARTA unit includes one 1.5x1.2 m 2 RPC, with 64 pickup electrodes (pads). The DAQ sys- tem is based on an ASIC, allowing one to read out the high number of channels with low power consumption. Data are recorded using a dual technique: single particle counting with a simple threshold on the signal from each pad and charge integration for high occupancy. The RPC, DAQ, High Voltage and monitoring systems are enclosed in an aluminum-sealed case, providing a com- pact and robust unit suited for outdoor environments, which can be easily deployed and connected. The RPCs developed at LIP-Coimbra are able to operate using very low gas flux, which allows running them for few years with a small gas reservoir. Several full-scale units are already installed and taking data in several locations and with different configurations, proving the viability of the MARTA concept. By shielding the detector units with enough slant mass to absorb the electro- magnetic component in the air showers, a clean measurement of the muon content is allowed, a concept to be implemented in a next generation of UHECR experiments. The specificities of a MARTA unit are presented, which include particle counting with high efficiency, time resolu- tion and spatial segmentation. The potential of the MARTA concept for muon measurements in air showers is assessed, as well as tentative methods for calibration and cross-calibrations with existing detectors.