17 research outputs found
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An explicit state-space approach to the one-block super-optimal distance problem
An explicit state-space approach is presented for solving the super-optimal Nehari-extension problem. The approach is based on the all-pass dilation technique developed in (Jaimoukha and Limebeer in SIAM J Control Optim 31(5):1115â1134, 1993) which offers considerable advantages compared to traditional methods relying on a diagonalisation procedure via a Schmidt pair of the Hankel operator associated with the problem. As a result, all derivations presented in this work rely only on simple linear-algebraic arguments. Further, when the simple structure of the one-block problem is taken into account, this approach leads to a detailed and complete state-space analysis which clearly illustrates the structure of the optimal solution and allows for the removal of all technical assumptions (minimality, multiplicity of largest Hankel singular value, positive-definiteness of the solutions of certain Riccati equations) made in previous work (Halikias et al. in SIAM J Control Optim 31(4):960â982, 1993; Limebeer et al. in Int J Control 50(6):2431â2466, 1989). The advantages of the approach are illustrated with a numerical example. Finally, the paper presents a short survey of super-optimization, the various techniques developed for its solution and some of its applications in the area of modern robust control
Expansion cone for the 3-inch PMTs of the KM3NeT optical modules
[EN] Detection of high-energy neutrinos from distant astrophysical sources will open a new window on the Universe. The detection principle exploits the measurement of Cherenkov light emitted by charged particles resulting from neutrino interactions in the matter containing the telescope. A novel multi-PMT digital optical module (DOM) was developed to contain 31 3-inch photomultiplier tubes (PMTs). In order to maximize the detector sensitivity, each PMT will be surrounded by an expansion cone which collects photons that would otherwise miss the photocathode. Results for various angles of incidence with respect to the PMT surface indicate an increase in collection efficiency by 30% on average for angles up to 45 degrees with respect to the perpendicular. Ray-tracing calculations could reproduce the measurements, allowing to estimate an increase in the overall photocathode sensitivity, integrated over all angles of incidence, by 27% (for a single PMT). Prototype DOMs, being built by the KM3NeT consortium, will be equipped with these expansion cones.This work is supported through the EU, FP6 Contract no. 011937, FP7 grant agreement no. 212252, and the Dutch Ministry of Education, Culture and Science.AdriĂĄn MartĂnez, S.; Ageron, M.; Aguilar, JA.; Aharonian, F.; Aiello, S.; Albert, A.; Alexandri, M.... (2013). Expansion cone for the 3-inch PMTs of the KM3NeT optical modules. Journal of Instrumentation. 8(3):1-19. https://doi.org/10.1088/1748-0221/8/03/T03006S1198
Detection potential of the KM3NeT detector for high-energy neutrinos from the Fermi bubbles
A recent analysis of the Fermi Large Area Telescope data provided evidence for a high-intensity emission of high-energy gamma rays with a E 2 spectrum from two large areas, spanning 50 above and below the
Galactic centre (the ââFermi bubblesââ). A hadronic mechanism was proposed for this gamma-ray emission making the Fermi bubbles promising source candidates of high-energy neutrino emission. In this work Monte Carlo simulations regarding the detectability of high-energy neutrinos from the Fermi bubbles
with the future multi-km3 neutrino telescope KM3NeT in the Mediterranean Sea are presented. Under the hypothesis that the gamma-ray emission is completely due to hadronic processes, the results indicate
that neutrinos from the bubbles could be discovered in about one year of operation, for a neutrino spectrum with a cutoff at 100 TeV and a detector with about 6 km3 of instrumented volume. The effect of a
possible lower cutoff is also considered.Published7â141.8. Osservazioni di geofisica ambientaleJCR Journalrestricte
Measurement of light scattering in deep sea
The deep-sea neutrino telescope in the Mediterranean Sea, being prepared by the KM3NET collaboration, will contain thousands of optical sensors to readout. The accurate knowledge of the optical properties of deep-sea water is of great importance for the neutrino event reconstruction process. In this study we describe our progress in designing an experimental setup and studying a method to measure the parameters describing the absorption and scattering characteristics of deep-sea water. Three PMTs will be used to measure in situ the scattered light emitted from six laser diodes in three different wavelengths covering the Cherenkov radiation spectrum. The technique for the evaluation of the parameters is based on Monte Carlo simulations and our results show that we are able to determine these parameters with satisfying precision
Measurement of light scattering in deep sea
The deep-sea neutrino telescope in the Mediterranean Sea, being prepared by the KM3NET collaboration, will contain thousands of optical sensors to readout. The accurate knowledge of the optical properties of deep-sea water is of great importance for the neutrino event reconstruction process. In this study we describe our progress in designing an experimental setup and studying a method to measure the parameters describing the absorption and scattering characteristics of deep-sea water. Three PMTs will be used to measure in situ the scattered light emitted from six laser diodes in three different wavelengths covering the Cherenkov radiation spectrum. The technique for the evaluation of the parameters is based on Monte Carlo simulations and our results show that we are able to determine these parameters with satisfying precision
Measurement of light scattering in deep sea
The deep-sea neutrino telescope in the Mediterranean Sea, being prepared by the KM3NET collaboration, will contain thousands of optical sensors to readout. The accurate knowledge of the optical properties of deep-sea water is of great importance for the neutrino event reconstruction process. In this study we describe our progress in designing an experimental setup and studying a method to measure the parameters describing the absorption and scattering characteristics of deep-sea water. Three PMTs will be used to measure in situ the scattered light emitted from six laser diodes in three different wavelengths covering the Cherenkov radiation spectrum. The technique for the evaluation of the parameters is based on Monte Carlo simulations and our results show that we are able to determine these parameters with satisfying precision
The New Small Wheel electronics
The increase in luminosity, and consequent higher backgrounds, of the LHC
upgrades require improved rejection of fake tracks in the forward region of the
ATLAS Muon Spectrometer. The New Small Wheel upgrade of the Muon Spectrometer
aims to reduce the large background of fake triggers from track segments that
are not originated from the interaction point. The New Small Wheel employs two
detector technologies, the resistive strip Micromegas detectors and the "small"
Thin Gap Chambers, with a total of 2.45 Million electrodes to be sensed. The
two technologies require the design of a complex electronics system given that
it consists of two different detector technologies and is required to provide
both precision readout and a fast trigger. It will operate in a high background
radiation region up to about 20 kHz/cm at the expected HL-LHC luminosity
of =7.5cms. The architecture of the
system is strongly defined by the GBTx data aggregation ASIC, the
newly-introduced FELIX data router and the software based data handler of the
ATLAS detector. The electronics complex of this new detector was designed and
developed in the last ten years and consists of multiple radiation tolerant
Application Specific Integrated Circuits, multiple front-end boards, dense
boards with FPGA's and purpose-built Trigger Processor boards within the ATCA
standard. The New Small Wheel has been installed in 2021 and is undergoing
integration within ATLAS for LHC Run 3. It should operate through the end of
Run 4 (December 2032). In this manuscript, the overall design of the New Small
Wheel electronics is presented.Comment: 61 page
NESTOR experiment in 2003
NESTOR is a submarine high-energy muon and neutrino telescope, now under construction for deployment in the Mediterranean close to Greek shores. The first floor of NESTOR with 12 optical modules was deployed successfully in March 2003 together with the electronics system. All systems and the associated environmental monitoring units are operating properly and data are being recorded. The status of the NESTOR project is presented. We outline briefly the construction of the deepwater neutrino telescope, properties of the NESTOR site, infrastructure of the project, the deployment of the first floor, and its current operation. The first data are presented and plans for the next steps are summarized. © 2004 MAIK "Nauka/Interperiodica"
KM3NeT: Technical design report.
KM3NeT is a deepâsea multidisciplinary observatory in the Mediterranean Sea that will provide innovative science
opportunities spanning Astroparticle Physics and Earth and Sea Science. This is possible through the synergy created by the use of a common infrastructure allowing for long term continuous operation of a neutrino telescope and marine
instrumentation. The present KM3NeT Design Study concludes with this Technical Design Report which develops the ideas put forward in the Conceptual Design Report published in April 2008