10 documents found, page 1 of 1
Measurement of the n_TOF beam profile with a micromegas detector
Pancin, J.; Abbondanno, U.; Aerts, G.; Alvarez, H.; Andriamonje, S.; Angelopoulos, A.; Assimakopoulos, P.; Bacri, C.; Badurek, G.; Baumann, P.A Micromegas detector was used in the neutron Time-Of-Flight (n_TOF) facility at CERN to evaluate the spatial distribution of the neutron beam as a function of its kinetic energy. This was achieved over a large range of neutron energies by using two complementary processes: at low energy by capture of a neutron via the 6Li(n,[alpha])t reaction, and at high energy by elastic scattering of neutrons on gas nuclei ...
Progress in timing Resistive Plate Chambers
Blanco, A.; Carolino, N.; Correia, C. M. B. A.; Ferreira-Marques, R.; Fonte, P.; Gobbi, A.; González-Díaz, D.; Lopes, M. I.; Lopes, L.; Macedo, M. P.Timing RPCs are Resistive Plate Chambers made with glass and metal electrodes separated by precision spacers. Typical gas gaps are a few hundred micrometers wide. Such counters were introduced in 1999 and have since reached timing accuracies below 50 ps [sigma] with efficiencies above 99% for MIPs. Applications in high-energy physics have already taken place with several more under study.; http://www.sciencedir...
Development of high-rate timing RPCs
Lopes, L.; Marques, R. Ferreira; Fonte, P.; Pereira, A.; Peskov, V.; Policarpo, A.For many applications of RPCs to time-of-flight counters in heavy ion experiments the expansion to much higher values of the counting rate capability, so far limited to around 2 kHz/cm2 is of fundamental importance. To address this issue we developed single-gap timing RPCs with resistive electrodes made from a commercially available plastic material. Tests performed in photon beams yielded a time resolution aro...
Perspectives for positron emission tomography with RPCs
Blanco, A.; Chepel, V.; Ferreira-Marques, R.; Fonte, P.; Lopes, M. I.; Peskov, V.; Policarpo, A.In this study, we address the feasibility and main properties of a positron emission tomograph (PET) based on RPCs. The concept, making use of the converter-plate principle, takes advantage of the intrinsic layered structure of RPCs and its simple and economic construction. The extremely good time and position resolutions of RPCs also allow the TOF-PET imaging technique to be considered.; http://www.sciencedire...
High-resolution TOF with RPCs
Fonte, P.; Peskov, V.In this work, we describe some recent results concerning the application of Resistive Plate Chambers operated in avalanche mode at atmospheric pressure for high-resolution time-of-flight measurements. A combination of multiple, mechanically accurate, thin gas gaps and state-of-the-art electronics yielded an overall (detector plus electronics) timing accuracy better than 50 ps [sigma] with a detection efficiency...
Single-electron pulse-height spectra in thin-gap parallel-plate chambers
Fonte, P.; Ferreira-Marques, Rui; Peskov, V.; Policarpo, A.Single-electron pulse-height spectra were measured in 0.6 and 1.2 mm parallel-plate chambers developed for the TOF system of the ALICE/LHC-HI experiment. Mixtures of Ar with ethane, isobutane, and SF6 were studied. The observed spectrum shows a clear peak for all gases, suggesting efficient single-electron detection in thin parallel-plate structures. The pulse-height spectrum can be described by the weighted su...
A spark-protected high-rate detector
Fonte, P.; Carolino, N.; Costa, L.; Ferreira-Marques, Rui; Mendiratta, S.; Peskov, V.; Policarpo, A.We developed a very low resistivity RPC-type detector, the anode of which was a plate made from materials with resistivity up to 5×107 [Omega] cm, the cathode being a metallic mesh preceded by a drift region.; http://www.sciencedirect.com/science/article/B6TJM-3WX21P9-J/1/b56046b528d4eca75db4fdb2995304b5
Breakdown limit studies in high-rate gaseous detectors
Ivaniouchenkov, Yu.; Fonte, P.; Peskov, V.; Ramsey, B. D.We report results from a systematic study of breakdown limits for novel high-rate gaseous detectors: MICROMEGAS, CAT and GEM, together with more conventional devices such as thin-gap parallel-mesh chambers and high-rate wire chambers. It was found that for all these detectors, the maximum achievable gain, before breakdown appears, drops dramatically with incident flux, and is sometimes inversely proportional to...
Rate and gain limitations of MSGCs and MGCs combined with GEM and other preampl...
Fonte, P.; Peskov, V.; Ramsey, B. D.We have studied the rate and gain limits of diamond-coated Microstrip Gas Counters (MSGCs) and Micro-Gap Counters (MGCs) when combined with various preamplification structures: Gas Electron Multiplier (GEM), Parallel-Plate Avalanche Chamber (PPAC) or a MICROMEGAS-type structure. Measurements were done both with X-rays and alpha particles with various detector geometries and in different gas mixtures at pressure...
A study of breakdown limits in microstrip gas counters with preamplification st...
Fonte, P.; Peskov, V.; Ramsey, B. D.We have studied the charge and breakdown limits of Microstrip Gas Counters (MSGC's) with two different preamplification structures: the Gas Electron Multiplier (GEM) and the Parallel-Plate Avalanche Counter (PPAC). It was found that in both cases the breakdown limit was increased by 1-2 orders of magnitude compared to the bare MSGC and that this was due to the spreading of the primary electron cloud during pre-...