The influence of geometrical and design parameters of T‐jets mixers on flow dynamics and mixing patterns is studied by means of two‐dimensional computational fluid dynamics simulations, planar ...laser‐induced fluorescence, and test chemical reactions. The ratios between injector width and mixing chamber width and between width and depth of the mixing chamber were evaluated as parameters. These ratios determine the flow regime in T‐jets mixers: high values of injector/chamber width ratio favor mixing and high depth values also increase the flow dynamics and thus mixing. A strategy for scale‐up of T‐jets mixers is devised, based on increasing a noncritical dimension (depth) while keeping other dimensions small.
A new procedure is proposed to scale up T‐jets mixers, based on the identification of a noncritical dimension that can be increased without changing the mixing scales. This novel scale‐up does not affect micromixing and represents a favorable alternative to the traditional numbering‐up of microreactors to increase the throughput of an installation.
High-resolution timing of MIPs with RPCs – a model Fonte, P.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2000, Letnik:
456, Številka:
1
Journal Article
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Resistive Plate Chambers made with glass and metal electrodes forming accurately spaced gas gaps of a few hundred micrometers have reached timing accuracies below 50
ps
σ with efficiencies above 95%. ...This type of detector, operating at atmospheric pressure with non-flammable gases, seems well suited for large-area TOF systems, providing performances comparable to the existing scintillator-based TOF technology but with significantly lower price per channel. In this work we discuss the principles of operation and describe the performance of several chamber configurations.
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.
Currently the detection of Very High Energy gamma-rays for astrophysics rely on the measurement of the Extensive Air Showers (EAS) either using Cherenkov detectors or EAS arrays with larger field of ...views but also larger energy thresholds. In this talk we present a novel hybrid detector concept for a EAS array with an improved sensitivity in the lower energies (~ 100 GeV). We discuss its main features, capabilities and present preliminary results on its expected perfomances and sensitivities.This wide field of view experiment is planned to be installed at high altitude in South America making it a complementary project to the planned Cherenkov telescope experiments and a powerful tool to trigger further observations of variable sources and to detect transients phenomena.
The new HADES ToF Forward Detector Blanco, A.; Fonte, P.; Lopes, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
20/May , Letnik:
1050
Journal Article
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The High-Acceptance DiElectron Spectrometer (HADES) at GSI Darmstadt consists of a 6-coil toroidal magnet centered on the beam axis and six identical detection sections located between the coils and ...covering polar angles between 18° and 85°. The physics aims include the study of the properties of hot and dense hadronic matter as well as elementary and pion-induced reactions.
To increase the acceptance of HADES at very low polar angles in the forward region, between 0.5∘ and 7°, a new detector, the Forward Detector (FD), has been built. The FD is composed of a tracking and a Time Of Flight (TOF) detector based on Resistive Plate Chamber (RPC) technology. The TOF detector, covering an area of around 2 m2, is composed by 128 strip-like shielded RPC cells, with two different widths 22mm and 44mm and 750mm length distributed in four modules symmetrically placed around the beam axis. Each cell is composed by four gas gaps, 0.270mm, delimited by three (2mm) aluminum and two (1mm) glass electrodes. In order to cope with an expected maximum particle load of around 400 Hz/cm2, close to the beam axis, the detector is operated above room temperature in order to decrease the resistivity of the glass and increase the count rate capability.
Details of the system construction and results concerning timing precision are described in this communication. The detector was operated at 31.5 °C with a maximum particle load of around 600 Hz/cm2 during a production beam time for six weeks in early 2022 showing an average time precision of around 80 ps.
Research on cosmic rays is of big interest either for getting a better understanding about their origin and properties or because they offer very valuable information about the galactic, the solar ...and the Earth's environment. In order to improve our knowledge of all those fields, a high resolution cosmic ray tracking detector, TRAGALDABAS, is being commissioned at the Faculty of Physics of the Univ. of Santiago de Compostela (Spain). In this article we make overview of the main performances of the detector and we present some very preliminary results showing that the detector is taking good data, and that we are gathering a valuable sample of events, ready to be analyzed.
This communication describes test beam results, focusing on detection efficiency and timing precision, of common float glass timing Resistive Plate Chambers (tRPCs) exposed to a 2.7 GeV proton beam ...and operated at above ambient temperature in order to increase the count rate capability of the chambers, by exploiting the reduction in the resistivity of the glass electrodes. Results suggest that the count rate capability can be extended at least up to 1500Hz/cm2 when the detector is operated at 40.6°C without noticeable loss of efficiency or timing precision degradation with values around 90% and 100 ps, respectively, for this specific timing RPC arrangement.
A cylindrical gas flow ionization chamber has been developed for measuring particle energy in Scanning Transmission Ion Microscopy Tomography (STIM-T) experiments due to its ability to withstand the ...direct beam. The response of a He-iso-C4H10 filled ionization detector to 2MeV H+ and He+ beams was studied. Different operating parameters, such as concentration of isobutane (in the range of 55-100%), anode voltage, amplifier shaping time, the geometry of the detector entrance canal and the solid angle of the detector, were investigated. The stable operating plateau and the anode voltage at which the best energy resolution is attained were also determined for every gas mixture. The best energy resolution achieved so far for 2MeV H+ and He+ static beams was 1.3%, which is comparable to that of Si PIN diode detectors (in the range of 15-30keV). Computed tomography (CT) was applied to a set of STIM projections acquired with the gas ionization chamber at the IST/CTN microprobe beam line in order to visualize the 3D-mass distribution in a test structure.
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