573 research outputs found
Evidence base for recommendations for writing evidence-based syntheses
No full textUrsić L, Tokalić R, Buljan I, Matas J, Utrobicic A, Marusic A. Evidence base for recommendations for writing evidence-based syntheses. Cochrane Database of Systematic Reviews 2023, Issue 10. Art. No.: MR000067
Development of Conflict-Free Environmentally Friendly Departure Routes in a Spoke-Wheel Airspace Structure
No full textIn a state-of-the-art major airport, like for example Munich International Airport, almost
the whole arriving traffic is heavily restricted in terms of airspeed, vertical speed or
cleared altitudes by Air Traffic Control (ATC) [3]. Concerning the trajectories flown by
different aircraft, so-called trombones including a downwind, base leg and final are
planned by the Air Traffic Controllers to make best use of the available capacity.
Consequently, every approach flown by an aircraft under ATC restrictions cannot be
executed at an optimum level of efficiency in terms of fuel burn or noise emissions.
Likewise, the departing traffic is heavily restricted as well, for example by late climb
clearances which lead to long level flights at low altitudes and consequently high noise
and fuel emissions.
Therefore, the German Aerospace Center / Deutsches Zentrum für Luft- und
Raumfahrt e.V. (DLR) developed a new airspace structure design which is called the
Spoke-Wheel airspace structure [4]. In a Spoke-Wheel airspace structure, the aim is
to design certain arrival and approach routes in a way, so that a continuous descent
operation without a fundamental loss in capacity is possible [12]. An aircraft objected
to a continuous descent arrival route will commence descent by leaving its cruising
altitude and not stopping the descent until landing at the airfield. The main goal is to
avoid any intermittent level-off with the benefit of causing less noise, less fuel burn
and thus, less environmental damage [5]. Several projects and theses developed by
the DLR [4] have discussed the topic by suggesting an airspace structure in the SpokeWheel form. One factor which has not yet been thoroughly examined is the design of
departure routes in the proposed airspace with test phases at various international
airports. Initially, arriving traffic is prioritized over departing traffic, making it necessary
for departing traffic to level off early during climb or even plotting tremendously longer
departure tracks in order to allow for continuous descent operation of other aircraft.
This in turn has a negative impact in noise, fuel burn and general environmental
damage.
1.2
Rate-capability of the VMM3a front-end in the RD51 Scalable Readout System
No full textThe VMM3a is an Application Specific Integrated Circuit (ASIC), specifically developed for the readout of gaseous detectors. Originally developed within the ATLAS New Small Wheel (NSW) upgrade, it has been successfully integrated into the Scalable Readout System (SRS) of the RD51 collaboration. This allows, to use the VMM3a also in small laboratory set-ups and mid-scale experiments, which make use of Micro-Pattern Gaseous Detectors (MPGDs). As part of the integration of the VMM3a into the SRS, the readout and data transfer scheme was optimised to reach a high rate-capability of the entire readout system and profit from the VMM3a’s high single-channel rate-capability of 3.6Mhits/s. The optimisation focused mainly on the handling of the data output stream of the VMM3a, but also on the development of a trigger-logic between the front-end cards and the DAQ computer. In this article, two firmware implementations of the non-ATLAS continuous readout mode are presented, as well as the implementation of the trigger-logic. Afterwards, a short overview on X-ray imaging results is presented, to illustrate the high rate-capability from an application point-of-view.The VMM3a is an Application Specific Integrated Circuit (ASIC), specifically developed for the readout of gaseous detectors. Originally developed within the ATLAS New Small Wheel (NSW) upgrade, it has been successfully integrated into the Scalable Readout System (SRS) of the RD51 collaboration. This allows, to use the VMM3a also in small laboratory set-ups and mid-scale experiments, which make use of Micro-Pattern Gaseous Detectors (MPGDs). As part of the integration of the VMM3a into the SRS, the readout and data transfer scheme was optimised to reach a high rate-capability of the entire readout system and profit from the VMM3a's high single-channel rate-capability of 3.6 Mhits/s. The optimisation focused mainly on the handling of the data output stream of the VMM3a, but also on the development of a trigger-logic between the front-end cards and the DAQ computer. In this article, two firmware implementations of the non-ATLAS continuous readout mode are presented, as well as the implementation of the trigger-logic. Afterwards, a short overview on X-ray imaging results is presented, to illustrate the high rate-capability rom an application point-of-view
Electrical discharge propagation between GEM foils
No full textThis paper presents the studies of fast sequential discharge formations in neighboring Gas Electron Multiplier foils (so called fast discharge propagations). We report on the characteristics of the time delay between the discharges, which has been shown to be of the order of tens of nanoseconds. This time delay decreases both with increasing voltage on the foil where the secondary discharge occurs as well as with decreasing distance between the neighboring foils. Optical measurements of the discharges in two- and three-stage detector setups show that the propagating discharge does not occur directly below the primary discharge, but is displaced from the shortest line between neighboring foils. This observation, together with Scanning Electron Microscope and Energy Dispersive Spectroscopy analyses of the material deposited below the position of the primary discharge provide valuable information on the time evolution of the fast discharge propagation through the detector and its formation mechanism. In the light of these findings, we propose and discuss a new hypothesis for the occurrence of the secondary discharges
First Observation of an Attractive Interaction between a Proton and a Cascade Baryon
No full textThis Letter presents the first experimental observation of the attractive strong interaction between a
proton and a multistrange baryon (hyperon) Ξ−. The result is extracted from two-particle correlations of
− ̄ þ pffiffiffiffiffiffiffi
⊕ p ̄ -Ξ pairs measured in p-Pb collisions at sNN 1⁄4 5.02 TeV at the LHC with ALICE.
combined p-Ξ
The measured correlation function is compared with the prediction obtained assuming only an attractive Coulomb interaction and a standard deviation in the range [3.6, 5.3] is found. Since the measured p-Ξ− ⊕ p ̄-Ξ ̄þ correlation is significantly enhanced with respect to the Coulomb prediction, the presence of an additional, strong, attractive interaction is evident. The data are compatible with recent lattice calculations by the HAL-QCD Collaboration, with a standard deviation in the range [1.8, 3.7]. The lattice potential predicts a shallow repulsive Ξ− interaction within pure neutron matter and this implies stiffer equations of state for neutron-rich matter including hyperons. Implications of the strong interaction for the modeling of neutron stars are discussed
Induced signals in particle detectors with resistive elements: Numerically modeling novel structures (VCI 2022)
No full textFor detectors with resistive elements, the time dependence of the signals is not solely given by the movement of the charges in the drift medium but also by the time-dependent reaction of the resistive materials. In this report, we present a numerical way to capture this contribution by using the extended form of the Ramo–Shockley theorem for conductive media. As an example, the methodology will be applied to the MicroCAT two-dimensional interpolation readout to calculate the center of gravity position reconstruction distortion map of its readout cells
Investigating correlated fluctuations of conserved charges with net-A fluctuations in Pb-Pb collisions at ALICE
No full textEvent-by-event fluctuations of conserved charges such as electric
charge, strangeness, and baryon number - in ultrarelativistic heavy-ion
collisions provide insight into the properties of the quark-gluon plasma
and the QCD phase diagram. They can be related to the higher moments of
the multiplicity distributions of identified particles, such as the A
baryon which carries both strangeness and baryon number and is thus of
particular interest. We present the first measurement of net-A
fluctuations in Pb-Pb collisions at root s(NN)=5.02 TeV as a function of
centrality and the pseudorapidity acceptance of the measurement. The
results are compared to expectations of the effects of global baryon
number conservation as well as to predictions from the HIJING Monte
Carlo event generator. In this analysis the Identity Method is applied
in a novel way to account for the combinatoric background in the
invariant mass distribution
A novel diamond-like carbon based photocathode for PICOSEC Micromegas detectors
No full textThe PICOSEC Micromegas (MM) detector is a precise timing gaseous detector based on a MM detector operating in a two-stage amplification mode and a Cherenkov radiator. Prototypes equipped with cesium iodide (CsI) photocathodes have shown promising time resolutions as precise as 24 picoseconds (ps) for Minimum Ionizing Particles. However, due to the high hygroscopicity and susceptibility to ion bombardment of the CsI photocathodes, alternative photocathode materials are needed to improve the robustness of PICOSEC MM. Diamond-like Carbon (DLC) film have been introduced as a novel robust photocathode material, which have shown promising results. A batch of DLC photocathodes with different thicknesses were produced and evaluated using ultraviolet light. The quantum efficiency measurements indicate that the optimized thickness of the DLC photocathode is approximately 3 nm. Furthermore, DLC photocathodes show good resistance to ion bombardment in aging test compared to the CsI photocathode. Finally, a PICOSEC MM prototype equipped with DLC photocathodes was tested in muon beams. A time resolution of around 42 ps with a detection efficiency of 97% for 150 GeV/c muons were obtained. These results indicate the great potential of DLC as a photocathode for the PICOSEC MM detector
Investigating correlated fluctuations of conserved charges with net-A fluctuations in Pb-Pb collisions at ALICE
No full textEvent-by-event fluctuations of conserved charges such as electric charge, strangeness, and baryon number - in ultrarelativistic heavy-ion collisions provide insight into the properties of the quark-gluon plasma and the QCD phase diagram. They can be related to the higher moments of the multiplicity distributions of identified particles, such as the A baryon which carries both strangeness and baryon number and is thus of particular interest. We present the first measurement of net-A fluctuations in Pb-Pb collisions at root s(NN)=5.02 TeV as a function of centrality and the pseudorapidity acceptance of the measurement. The results are compared to expectations of the effects of global baryon number conservation as well as to predictions from the HIJING Monte Carlo event generator. In this analysis the Identity Method is applied in a novel way to account for the combinatoric background in the invariant mass distribution
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