45 research outputs found
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CMOS-compatible SOI micro-hotplate-based oxygen sensor
© 2016 IEEE. The paper reports upon the design and characterization of a resistive O2 sensor, which is fully CMOS-compatible and is based on an ultra-low-power Silicon on Insulator (SOI) micro-hotplate membrane. The microsensor employs SrTi0.4Fe0.6O2.8 (STFO60) as sensing layer. Thermo-Gravimetric Analysis (TGA) Energy-Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) techniques have been used to assess the quality of both the sensing layer and STFO-SOI interface. At room temperature, the SOI sensor shows good sensitivity and fast response time (†6 seconds) to O2 concentration ranging from 0% to 20% in a nitrogen atmosphere. This is the first experimental result showing the potential of this structure as O2 sensor
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Nanostructured metal oxides semiconductors for oxygen chemiresistive sensing
Nanostructured metal oxide semiconductors have been widely investigated and are commonly used in gas sensing structures. After a brief review which will be focused on chemiresistive oxygen sensing employing this type of sensing materials, for both room temperature and harsh environment applications (particularly, at high ambient temperature and high relative humidity levels), paper reports new results concerning O2detection of a structure using a sensing layer comprising nanostructured (typical grain size of 50 nm) SrTi0.6Fe0.4O2.8(STFO40), synthesized by sonochemical methods, mixed with single wall carbon nanotubes. The structure is a Microelectromechanical System (MEMS), based on a Silicon-on-Insulator (SOI), Complementary Metal-Oxide-Semiconductor (CMOS)-compatible micro-hotplate, comprising a tungsten heater which allows an excellent control of the sensing layer working temperature. Oxygen detection tests were performed in both dry (RH = 0%) and humid (RH = 60%) nitrogen atmosphere, varying oxygen concentrations between 1% and 20% (v/v), at a constant heater temperature of 650 °C
Elektrische LeitfÀhigkeit dichter, schwerioneninduzierter Plasmen
Intensive Ionenstrahlen sind besonders geeignet groĂe Volumina von hoher Energiedichte in Materie mit einer guten HomogenitĂ€t der Verteilung physikalischer Parameter zu erzeugen. Die experimentelle Erforschung von Materie unter extremen ZustĂ€nden von Druck, Temperatur und Dichte ist von hohem Interesse sowohl fĂŒr die Grundlagenforschung als auch fĂŒr die angewandte Physik. Dazu gehören Fragen der Astrophysik, Geophysik und der Energiegewinnung mit Hilfe der TrĂ€gheitsfusion. Zur Erforschung der Materie bei hoher Energiedichte gehören insbesondere Experimente zur thermodynamischen Zustandsgleichung und zu Transporteigenschaften. Die elektrische LeitfĂ€higkeit ist eine der fundamentalen Eigenschaften der Materie. Obwohl in den letzten Jahrzehnten das theoretische VerstĂ€ndnis der elektrischen LeitfĂ€higkeit bedeutende Fortschritte gemacht hat, gibt es weiterhin keine allgemeine Theorie, welche das Verhalten dieses Transportkoeffizienten unter unterschiedlichen Bedingungen vorhersagen kann. Deswegen sind Messungen dieser GröĂe von besonderer Bedeutung fĂŒr die Grundlagenforschung. Zum ersten Mal wurden am Hochtemperaturmessplatz (HHT) der Plasmaphysikgruppe der Gesellschaft fĂŒr Schwerionenforschung (GSI) Darmstadt Messungen zur elektrischen LeitfĂ€higkeit dichter, schwerioneninduzierter Plasmen durchgefĂŒhrt. Zu diesem Zweck wurden Drahtförmige Festkörpertargets aus unterschiedlichen Materialien (Kupfer, Blei, Silber) mit hochintensiven Schwerionenstrahlen bis auf Temperaturen im Bereich von 0,1 eV innerhalb von 0.001 ms geheizt. Wegen der kurzen Heizzeit bleibt die Dichte der Targets in der NĂ€he der Festkörperdichte und der Druck steigt bis zu einigen kbar. Die LeitfĂ€higkeit dieser Targets wurde mit Hilfe von am HHT neu entwickelten experimentellen Techniken untersucht. Die durchgefĂŒhrten Messungen lieferten zeitaufgelöste Daten sowohl zur Ănderung des elektrischen Widerstandes der Targets als auch zu ihrer hydrodynamischen Expansion, und ermöglichten dadurch die Bestimmung des spezifischen elektrischen Widerstandes, beziehungsweise der elektrischen LeitfĂ€higkeit. DarĂŒber hinaus wurden komplexe Simulationen durchgefĂŒhrt, um theoretische Vorhersagen mit den Resultaten dieser Messungen zu vergleichen. Wir sind davon ĂŒberzeugt, dass die gewonnenen Erfahrungen und entwickelten Diagnostikmethoden fĂŒr zukĂŒftige Experimente sehr wichtig sein werden, insbesondere im Rahmen des GSI Zukunftprojektes
Simulations of Space-Charge and Guiding Fields Effects on the Performance of Gas Jet Profile Monitoring
Gas jet based profile monitors inject a usually curtain shaped gas jet across a charged particle beam and exploit the results of the minimally invasive beam-gas interaction to provide information about the beamâs transversal profile. Such monitor will be installed as part of the High Luminosity LHC upgrade at CERN in the Hollow Electron Lens (HEL). The HEL represents a new collimation stage increasing the diffusion rate of halo particles by placing a high intensity hollow electron beam concentrically around the LHC beam. The gas jet monitor will use the fluorescence radiation resulting due to the beam-gas interaction to create an image of the profiles of both hollow electron and LHC beams However, the high beam space-charge and strong guiding magnetic field of the electron beam cause significant displacements of the excited molecules, as they are also ionized, and thus image distortions. This work presents preliminary simulation results showing expected fluorescence images of the hollow electron profile as affected by space-charge and guiding fields using simulation tools such as IPMsim. The influence of the estimated electron beam and gas jet curtain parameters are investigated
Design and Test of Beam Diagnostics Equipment for the FAIR Proton Linac
A dedicated proton injector Linac (pLinac) for the Facility of Antiproton and Ion Research (FAIR) at GSI, Darmstadt, is currently under construction. It will provide a 68 MeV, up to 70 mA proton beam at a duty cycle of max. 35”s / 2.7 Hz for the SIS18/SIS100 synchrotrons, using the existing UNILAC transfer beamline. After further acceleration in SIS100, the protons are mainly used for antiproton production at the Pbar ANnihilations at DArmstadt (PANDA) experiment. The Linac will operate at 325 MHz and consists of a novel so called âLadderâ RFQ type, followed by a chain of CH-cavities, partially coupled by rf-coupling cells. In this paper we present the beam diagnostics system for the pLinac with special emphasis on the Secondary Electron Emission (SEM) Grids and the Beam Position Monitor (BPM) system. We also describe design and status of our diagnostics testbench for stepwise Linac commissioning, which includes an energy spectrometer with associated optical system. The BPMs and SEM grids have been tested with proton and argon beam during several beamtimes in 2022. The results of these experiments are presented and discussed