Fabrizio Ameli

Performance analysis of a DWDM optical transmission system

Dense Wavelength Division Multiplexing (DWDM) is an optical technology which allows transmitting across a fiber many wavelengths, which can be added and dropped by means of passive optical components. We present and discuss the performance of a complex DWDM network data transmission system that will find an application in the NEMO underwater neutrino telescope.

The NEMO experiment data acquisition and timing distribution systems

Many high energy physics experiments (Auger, Ice-Cube, Km3Net) currently taking data or planned in the near future consist of big and sparse detectors that acquire a huge amount of data. This kind of topology requires the ability to acquire physics information in different places of the detector and correlate them using the occurrence time, usually with a sub-ns precision. In some cases this can be done using commercially available technologies, for instance the Auger experiment uses a GPS receiver in each surface tank to “time stamp” the produced data, but in many cases this is not possible. In underwater or underground detectors the GPS signal cannot reach the apparatus so a different approach must be used. In order to minimize the number of physical links and to guarantee the timing synchronization of the apparatus, data and clock information can be transmitted over the same serial stream. This work presents a synchronous link with fixed and deterministic latency based on the embedded transceivers of the Xilinx Virtex-5 FPGA family. This communication channel is used to implement the data acquisition system for the NEMO experiment. The whole timing distribution chain has been taken into consideration to assess the performance of the readout electronics in terms of timing resolution. The system clock distributed at every level of the apparatus has been derived by a precise timing generator during the characterization phase and by the signals provided by a GPS receiver during the operating configuration. The overall timing performance comply with the requirements of the experiment, yielding a rms timing resolution of about 20 ps.

A time-to-digital converter based on a digitally controlled oscillator

Time measurements play a crucial role in trigger and data acquisition systems of high-energy physics experiments, where synchronization between system elements, signal calibration, and phase-measurement accuracy is often required. In this paper, we present a fully digital time-to-digital converter (TDC) architecture and its application, based on a synthesizable digitally controlled oscillator (DCO), where the TDC is used to measure the phase relationship between a timing signal and a 40-MHz reference clock. The DCO design is technology independent; it is described by means of a hardware description language and it can be placed and routed with automatic tools. The TDC will be used in the new readout chip that is under development for the muon detector electronic upgrade in Large Hadron Collider beauty experiment at CERN. The TDC presented in this paper has the fundamental task of measuring, with a resolution of about 1.5 ns, the phase difference between the 40-MHz LHC machine clock and a digital signal coming from the muon detector.

NEMO-SN1 (Western Ionian Sea, off Eastern Sicily): Example of architecture of a cabled observatory

NEMO-SN1, located in the central Mediterranean Sea, Western Ionian Sea, off Eastern Sicily Island (Southern Italy) at 2100 m water depth, 25 km from the harbour of the city of Catania, is a prototype of a cabled deep-sea multiparameter observatory and the first operating with real-time data transmission in Europe since 2005. NEMO-SN1 is also the first-established node of EMSO (European Multidisciplinary Seafloor Observatory, http://emso-eu.org), one of the incoming European large-scale research infrastructure included since 2006 in the Roadmap of the ESFRI (European Strategy Forum on Research Infrastructures, http://cordis.europa.eu/esfri/roadmap.htm), which will specifically address long-term monitoring of environmental processes related to Marine Ecosystems, Climate Change and Geo-hazards. NEMO-SN1 has been deployed and developed over the last decade thanks to Italian resources and to the EC project ESONET-NoE (European Seas Observatory NETwork — Network of Excellence, 2007–2011) that funded the LIDO-DM (Listening to the Deep Ocean — Demonstration Mission) and a technological interoperability test (http://www.esonet-emso.org/esonet-noe/). NEMO-SN1 is performing geophysical and environmental long-term monitoring by acquiring seismological, geomagnetic, gravimetric, accelerometric, physico-oceanographic, hydro-acoustic, bio-acoustic measurements specifically related to earthquakes and tsunamis generation and ambient noise characterisation in term of marine mammal sounds, environmental and anthropogenic sources. A further main feature of NEMO-SN1 is to be an important test-site for the construction of KM3NeT (Kilometre-Cube Underwater Neutrino Telescope, http://www.km3net.org/), another large-scale research infrastructure included in the ESFRI Roadmap constituted by a large volume neutrino telescope. The description of the observatory and the most recent data acquired will be presented and framed in the general objectives of EMSO.

Status and results from cabled hydrophones arrays deployed in deep sea off East Sicily (EMSO-ERIC node)

Since 2005 a cabled deep-sea infrastructure is operative at 2100 m water depth, 25 km off the port of Catania (Sicily). The infrastructure, under continuous improvement, is the first operative cabled node of the EMSO-ERIC, hosting several multidisciplinary observatories built in collaboration by INFN, INGV, CNR, CIBRA, and other scientific partners. Hydrophones antennas, sensitive in the range of frequencies between 1 Hz and 90 kHz, have been installed on seafloor observatories. Acoustic data are continuously digitized in situ at very high resolution, time-stamped with absolute GPS time and sent to shore in real time, through optical fiber link. Together with biological sounds, noise pollution study and monitoring were the main goals of the research. Results of multi-year monitoring of anthropogenic noise are discussed. Focus of the analysis is the noise level in the octave bands centered at 63 Hz and 125 Hz, in compliance with the EU Marine Strategy Framework Directive. The contribution of ship noise was...

A FPGA-based Network Interface Card with GPUDirect enabling realtime GPU computing in HEP experiments

Alessandro Lonardoa∗, Fabrizio Ameli, Roberto Ammendola, Andrea Biagioni, Angelo Cotta Ramusino, Massimiliano Fiorini, Ottorino Frezza, Gianluca Lamanna, Francesca Lo Cicero, Michele Martinelli, Ilaria Neri, Pier Stanislao Paolucci, Elena Pastorelli, Luca Pontisso , Davide Rossetti, Francesco Simeone, Francesco Simula, Marco Sozzi , Laura Tosoratto, Piero Vicini INFN Sezione di Roma Sapienza, P.le Aldo Moro, 2 00185 Roma, Italy INFN Sezione di Roma Tor Vergata, Via della Ricerca Scientifica, 1 00133 Roma, Italy Università degli Studi di Ferrara and INFN Sezione di Ferrara, Polo Scientifico e Tecnologico, Via Saragat 1 44122 Ferrara, Italy INFN Laboratori Nazionali di Frascati, Via E. Fermi,40 00044 Frascati (Roma), Italy CERN, CH-1211 Geneva 23, Switzerland f INFN Sezione di Pisa, Via F. Buonarroti 2 56127 Pisa, Italy NVIDIA Corp, 2701 San Tomas Expressway, Santa Clara, CA 95050

Performance Results of a Prototype Board Designed for Copper Data Transmission in KM3NeT

The experience gained in designing submarine neutrino telescopes suggests to explore new ways of realizing the data transmission backbone at the detection unit level for the KM3NeT project. In order to decrease the difficulties in integration and handling of the backbones, some effort has been spent in developing a backbone based on copper links with simple tracts of cable connecting contiguous storeys. This work is aimed at the presentation of the general architecture of the system, at the description of an electronic board prototype designed to test the project feasibility and the discussion of the first results obtained. The main goal of the experimental setup was measuring the recovered clock jitter under various conditions, with and without cables. The jitter measured on the cleaned clock amounts to hundreds of picoseconds, well below the sub-nanosecond time resolution required by this kind of experiments.

Performance study of a DWDM link with real-time characteristics

The Dense Wavelength Division Multiplexing is an optical technology which allows transmitting across a fiber many wavelengths, which can be added and dropped by means of passive optical components. A plugin link module, capable of building full duplex nodes in the Gb/s domain for systems with real-time requirements, is presented in this paper. To debug and characterize the link, the module is plugged into an host board developed for the NEMO experiment, a submarine neutrino telescope which has successfully applied the described technology. A specific application has been designed with the aim of measuring the performance of the module: an embedded processor on the FPGA initializes the link, starts BER test routines and monitors transceiver functionalities through the I2C bus. The communication with the processor is implemented by a simple RS232 asynchronous port. The performance in terms of BER and Jitter in dependance of power at the receiver is shown.