We discuss the introduction/implementation of optical IP routers, then we introduce a novel scheduling algorithm incorporating void filling and aimed at optical routing of asynchronous, variable ...packet length packets. We describe its structure and discuss the complexity issues. Albeit introduced with the purpose of cancelling expensive optical synchronization, we argue that this approach represents the most viable all-optical approach for implementing packets-over-SONET (IP-centric scenario). We also present simulations under self-similar traffic conditions which point to the inefficiency of optical buffering to combat the effects of self-similarity, and we outline alternative strategies for proper buffer dimensioning.
The Borexino detector at the Laboratori Nazionali del Gran Sasso Back, H.; Balata, M.; de Bellefon, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2009, Volume:
600, Issue:
3
Journal Article
Peer reviewed
Open access
Borexino, a large volume detector for low energy neutrino spectroscopy, is currently running underground at the Laboratori Nazionali del Gran Sasso, Italy. The main goal of the experiment is the ...real-time measurement of sub-MeV solar neutrinos, and particularly of the monoenergetic (862
keV)
7Be electron capture neutrinos, via neutrino–electron scattering in an ultra-pure liquid scintillator. This paper is mostly devoted to the description of the detector structure, the photomultipliers, the electronics, and the trigger and calibration systems. The real performance of the detector, which always meets, and sometimes exceeds, design expectations, is also shown. Some important aspects of the Borexino project, i.e. the fluid handling plants, the purification techniques and the filling procedures, are not covered in this paper and are, or will be, published elsewhere (see Introduction and Bibliography).
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IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This paper describes the typical mechanical and metallurgical characteristics of the austeno-ferritic steels for structural applications, with particular reference to their weldability.
Some examples ...of the uses of these materials for the construction of certain welded structures are also given.
The paper also discusses the various types of aluminium alloys and their advantages and disadvantages in the construction of welded structures.
General remarks regarding the welding processes commonly used are thus provided along with an overview of the welded structures built using aluminium alloys.
In this paper, the mechanical and metallurgical properties of duplex stainless steel for structural purposes are presented, with particular attention to their weldability. Some typical uses of these materials for welded structures are shown in detail.
This paper also deals with the use of aluminium alloys in welded structures pointing out the advantages and disadvantages. Information about suitable welding processes are also reported
.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
The motivations and application framework for the introduction of all-optical wavelength division multiplexing (WDM) transmission and routing techniques in the transport network are presented. The ...requirements and functionalities of all-optical transparent routing nodes are discussed, and the physical architecture of a crossconnection node is proposed, to meet these requirements. Optical devices suitable for the node implementation are compared, and first demonstrations of crossconnection function at data rates up to 10 Gb/s are given. These results bring experimental evidence of the high potential of all-optical routing nodes for actual implementation of multiwavelength transport networks.
The optical properties of various scintillators (both single components and their mixtures) have been measured in order to choose the scintillator composition offering the best compromise among the ...requirements of the large volume detector of the Borexino experiment on solar neutrinos. A pre-selection of the most interesting binary or ternary mixtures has been carried out by using a relatively simple and fast optical method. This is based on the UV excitation of the solvent and the observation of the emission properties in the spectral region of interest. The results obtained allowed the light output, response time and attenuation lengths to be evaluated for a broad range of mixtures. The mixtures offering the best properties for Borexino have been investigated in greater depth by using ionizing radiation as excitation source. The results were found to be in good agreement with those obtained by the optical method. In addition, the α quenching and the time response of the scintillators to α and β particles have been tested to evaluate the
α
β
discrimination capability.
The comparison of the results obtained in four laboratories using different techniques and methodologies, offered an exhaustive picture of the scintillator properties and provided the criteria for a good choice of the mixture for Borexino.
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This paper describes the work carried out in the RACE Project R2039 ATMOS (asynchronous transfer mode optical switching). The project is briefly illustrated, together with its main goal: to develop ...and assess concepts and technology suitable for optical fast packet switching. The project's technical approach consisted in the exploitation of the space and wavelength domains for fast routing and buffering: The major achievements are then reported. Four different switch architecture concepts have been proposed, investigated and developed, all based on a high speed optical routing matrix electrically controlled at lower speed. The basic optical key components and subsystems (wavelength converters, space switches and optical buffers) are described in detail, with the outstanding results obtained and the corresponding projected performance. In particular, system demonstration of wavelength conversion at 10 and 20 Gb/s has been realized, to show the usefulness of the ATMOS technology both to implement optimized high performance optical packet-switching fabrics as well as transparent optical circuit-routing nodes. Four rack-mounted, reduced size demonstrators of basic switching matrices have been designed and implemented scalable to real system sizes. The obtained good results in terms of bit error rate and hardware integration are reported, showing that ATM switches are feasible with state of-the-art optical technology.
This work, which is part of a wide collaboration for the study of solar neutrinos (the Borexino project at the Gran Sasso Laboratories), concerns the optimization of the fluorescent scintillation ...mixture of solvent and fluor(s) contained in the large-scale particle detector. The main aim of this work was to measure, under light excitation, the fluorescence efficiency and decay time and the wavelength-dependent attenuation length of various scintillator mixtures and their individual components. The absorption and emission properties have been analyzed using the Lambert- Beer law, to deduce the most appropriate composition of the scintillator mixtures on the basis of the best compromise among the different requirements of the detection system for the experiment. The results obtained on the optical properties of several mixtures investigated are reported and briefly discussed. Suggestions for the choice of an optimized mixture for the experiment are made.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The objective of this paper is to give an overview of the different studies we have performed at the research level regarding the design and implementation of a photonic wavelength division ...multiplexing (WDM) layer providing transparent transport services to client layers (SONET/SDH, ATM, etc.). Such a network requires a number of enabling factors to be assessed in order to become a reality. Among these factors are the availability of high-capacity WDM transmission systems and efficient optical routing nodes based on mature technology, the design of robust networks optimizing the utilization of resources, and the development of a management system in accordance with presently applied standards for transport networks. We review our achievements in these different fields.
The efficiency of quenching the fluorescence light in pseudocumene (PC) by the addition of pyridyl and phthalate derivatives (quenchers) has been studied both by ultraviolet excitation of PC and by ...using ionizing particles. The results show that a controlled reduction of the PC fluorescence is easily achieved by the addition of quencher in concentrations of a few grams per litre. The scintillation light can be quenched to a level where the Cherenkov light remains the only detectable signal when ionizing particles deposit energy in the solvent. While these data are of particular interest for the design of the Borexino buffer, more general applications of these results are envisaged and discussed.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Fluorescence and phosphorescence spectra, emission quantum yields and lifetimes, and triplet yields of camphorquinone have been measured in solvents of different polarities at room temperature. Rate ...coefficients of the excited state deactivation processes have been calculated. The results indicate that this molecule is an efficient triplet photosensitizer. An example of photosensitized reaction, followed from absorption measurements and phosphorescence quenching, is reported.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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