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