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Scientific Report 2007-2009
Laboratories and Facilities of the Department of Physics
L21. Nuclear Emulsion scanning Lab
Since over 6 decades researchers in Rome are exploiting the
emulsion technique applied to high-energy nuclear and particle
physics, i.e. tracking ionizing particles in photographic films by
high-magnification optical microscopes. As experiments evolved
in complexity (”hybrid” detectors made of electronic devices and
arrays of emulsion films) and scale (thousands of films to be
scanned), the quest for fast, automated (computer-driven) optical
microscopes, equipped with state-of-art TV cameras, stimulated
an impressive evolution of the technique, particularly in Japan
and in Europe.
As a result, the still active ”Emulsion scanning Lab” in Rome
appears different from its early glorious age. Formerly, there were
a lot of hand-operated optical microscopes, with many technicians
(”scanners”) busy to inspect by eye several optical fields per
hour. At present, a fast microscope system (see Fig. 1) is operational
under the full control of a computer, making ”tomography”
across photographic films. It could digest in real time some 200
bidimensional images per second, each of a few megapixel size,
Figure 1: The European Scanning System, an automated
optical microscope equipped with a fast, high resolution
CMOS camera. Details in [3].
taken at different focal depth. In parallel, a 3-dimensional pattern recognition is performed, such that fully documented
tracking data could be stored in a large data-base (terabyte scale).
The Emulsion scanning Lab in Rome is presently contributing to the data taking and event study of the OPERA experiment,
searching for neutrino oscillations induced by the CERN-to-Gran Sasso neutrino beam (CNGS). The scanning Lab is
a member of an european ”federation”, exploiting copies of the very same optical microscope system and a common software
framework, spread over several reasearch centers in Italy and abroad. Other Labs in Japan are in joint venture, contributing
to OPERA with different microscope systems of comparable performances.
Related research activities: P26.
L22. High Energy Astrophysical Neutrino Detection Laboratory
Our laboratory supported the several activities that, during the past decade, we have carried-out for the construction
of the future deep-sea Cherenkov detector for the detection of high-energy astrophysical neutrinos. In our lab we have
tested and calibrated the instruments for the measurement of the deep-sea environment in ANTARES site. We built special
electronic cards for their setting and control. Also for the NEMO and the KM3NeT projects we have developed, built
(mechanics, electronics and data acquisition system) and tested (before to operate them in deep sea) several ”autonomous
deep-sea measurement stations” to characterize the abyssal sites candidate for the Neutrino Telescope construction. All these
activities needed conventional tools for electronics, mechanics and software development and construction. We performed
careful studies of the characteristics of signals produced by the PMTs proposed for the construction of the Cherenkov
undersea Neutrino Telescope (NEMO, ANTARES, KM3NeT), mainly PMTs with large photocathode area (8”, 10”, 13”
diameter). We have built, for this work, in our lab a set-up that includes a blue laser for the PMT excitation and a full
electronic chain for data acquisition.
The main activity of the lab is the development of the electronic system for the real-time acquisition of signals produced by
the Neutrino Telescope system of PMTs located in deep-sea, about 100km far from the on-shore laboratory. This electronic
system has to be reliable, redundant and has to require low power for it’s operation. We developed and built the front-end
electronic cards to digitize (at 200 MHz) the PMT’s signals underwater ad to transmit ”all data to shore”. We also developed
and built the electronic system for the serial, high-speed and synchronous, transmission of all PMT’s data to shore. For
this work we did develop several different transmission protocols and serializer-deserializer devices. For NEMO-Phase1
prototype (a four floors mini-tower operated for few months in 2007, at 2000m depths) and for NEMO-Phase2 (a whole
tower deployed at 3500m depths in Capo Passero site) we built, tested and operated the full data acquisition/transmission
system (based on GLink chipset). At present we are contributing, with the acquired expertise, to the definition of the data
acquisition and transmission electronics system for KM3NeT. For these activities we used, in our lab, quite conventional
instruments/devices for the design and test of the electronics and the related firmware: a LeCroy Wavepro 7100A oscilloscope,
a logic analyzer Tektronix TLA714, a signal generator AGILENT 33250A, a PC farm. In our lab we also studied the basics for
the detection of acoustic signal produced by the interaction in deep-sea water of Ultra High Energy astrophysical Neutrino.
We characterised several hydrophones (specific for deep-sea use) in our lab and on a test beam; we developed and integrated
the data acquisition cards, needed for these sensors, into the main electronics system built for NEMO. For these studies we
can use a ”silent room” in our ”laboratory for acoustics”.
http://www.roma1.infn.it/people/capone/AHEN/index.htm/
Related research activities: P31, P32.
Sapienza Università di Roma 191 Dipartimento di Fisica