554 research outputs found
Prostorski vidiki načrtovanja logističnih središč: primer gospodarskega središča Feniks v Posavju
Prostorsko načrtovanje logističnih središč izhaja iz posebnih prostorskih in infrastrukturnih zahtev, ki jih pogojujeta obseg in želena pretočnost prometa. Prostorske in okoljske omejitve na običajnih pretovornih lokacijah silijo logistične dejavnosti v iskanje takšnih območij, ki omogočajo nemotene širitve in praktično neomejene prometne tokove. Posledica te težnje je suburbanizacija z vsemi prostorskimi in okoljskimi posledicami. Prispevek, v okviru zavedanja neponovljivosti posamezne lokacije, opozarja na pomen celovitosti in pravočasnosti prostorskega in okoljskega načrtovanja logističnih središč. V tem smislu se oblikovanje prostorskega koncepta, na jasnih prostorskih ciljih, transparentnih analitičnih izhodiščih in ustrezno prostorsko regulacijo, izkazuje kot zahteva prostorskega načrtovanja logističnih središč. Sočasno je, upoštevajoč zapletenost prostorskih ureditev, izpostavljen tudi pomen prostorske kohezije, ki se izraža kot prostorska identiteta, prostorska kakovost in prostorska učinkovitost
Neutron irradiation test of depleted CMOS pixel detector prototypes
Charge collection properties of depleted CMOS pixel detector prototypes
produced on p-type substrate of 2 kcm initial resistivity (by LFoundry
150 nm process) were studied using Edge-TCT method before and after neutron
irradiation. The test structures were produced for investigation of CMOS
technology in tracking detectors for experiments at HL-LHC upgrade.
Measurements were made with passive detector structures in which current pulses
induced on charge collecting electrodes could be directly observed. Thickness
of depleted layer was estimated and studied as function of neutron irradiation
fluence. An increase of depletion thickness was observed after first two
irradiation steps to 110 n/cm and 510
n/cm and attributed to initial acceptor removal. At higher fluences the
depletion thickness at given voltage decreases with increasing fluence because
of radiation induced defects contributing to the effective space charge
concentration. The behaviour is consistent with that of high resistivity
silicon used for standard particle detectors. The measured thickness of the
depleted layer after irradiation with 110 n/cm is more than
50 m at 100 V bias. This is sufficient to guarantee satisfactory
signal/noise performance on outer layers of pixel trackers in HL-LHC
experiments
Silicon Photomultiplier Research and Development Studies for the Large Size Telescope of the Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA) is the the next generation facility of
imaging atmospheric Cherenkov telescopes; two sites will cover both
hemispheres. CTA will reach unprecedented sensitivity, energy and angular
resolution in very-high-energy gamma-ray astronomy. Each CTA array will include
four Large Size Telescopes (LSTs), designed to cover the low-energy range of
the CTA sensitivity (20 GeV to 200 GeV). In the baseline LST design, the
focal-plane camera will be instrumented with 265 photodetector clusters; each
will include seven photomultiplier tubes (PMTs), with an entrance window of 1.5
inches in diameter. The PMT design is based on mature and reliable technology.
Recently, silicon photomultipliers (SiPMs) are emerging as a competitor.
Currently, SiPMs have advantages (e.g. lower operating voltage and tolerance to
high illumination levels) and disadvantages (e.g. higher capacitance and cross
talk rates), but this technology is still young and rapidly evolving. SiPM
technology has a strong potential to become superior to the PMT one in terms of
photon detection efficiency and price per square mm of detector area. While the
advantage of SiPMs has been proven for high-density, small size cameras, it is
yet to be demonstrated for large area cameras such as the one of the LST. We
are working to develop a SiPM-based module for the LST camera, in view of a
possible camera upgrade. We will describe the solutions we are exploring in
order to balance a competitive performance with a minimal impact on the overall
LST camera design.Comment: 8 pages, 5 figures. In Proceedings of the 34th International Cosmic
Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions
at arXiv:1508.0589
Raman LIDARs for the atmospheric calibrationalong the line-of-sight of CTA
The Cherenkov Telescope Array (CTA) is the next generation ground-based observatory forgamma-ray astronomy at very-high energies. Employing more than 100 Imaging AtmosphericCherenkov Telescopes in the northern and southern hemispheres, it was designed to reach un-precedented sensitivity and energy resolution. Understanding and correcting for systematic bi-ases on the absolute energy scale and instrument response functions will be a crucial issue forthe performance of CTA. The LUPM group and the Spanish/Italian/Slovenian collaboration arecurrently building two Raman LIDAR prototypes for the online atmospheric calibration alongthe line-of-sight of the CTA. Requirements for such a solution include the ability to characterizeaerosol extinction at two wavelengths to distances of 30 km with an accuracy better than 5%,within time scales of about a minute, steering capabilities and close interaction with the CTAarray control and data acquisition system as well as other auxiliary instruments. Our Raman LI-DARs have design features that make them different from those used in atmospheric science andare characterized by large collecting mirrors (∼2.5 m2), liquid light-guides that collect the light atthe focal plane and transport it to the readout system, reduced acquisition time and highly preciseRaman spectrometers. The Raman LIDARs will participate in a cross-calibration and character-ization campaign of the atmosphere at the CTA North site at La Palma, together with other sitecharacterization instruments. After a one-year test period there, an in-depth evaluation of the so-lutions adopted by the two projects will lead to a final Raman LIDAR design proposal for bothCTA sites
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
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