F. Caruso

Measurement of the atmospheric muon depth intensity relation with the NEMO Phase-2 tower

Abstract The results of the analysis of the data collected with the NEMO Phase-2 tower, deployed at 3500xa0m depth about 80xa0km off-shore Capo Passero (Italy), are presented. Cerenkov photons detected with the photomultipliers tubes were used to reconstruct the tracks of atmospheric muons. Their zenith-angle distribution was measured and the results compared with Monte Carlo simulations. An evaluation of the systematic effects due to uncertainties on environmental and detector parameters is also included. The associated depth intensity relation was evaluated and compared with previous measurements and theoretical predictions. With the present analysis, the muon depth intensity relation has been measured up to 13xa0km of water equivalent.

Status and first results of the NEMO Phase-2 tower

In March 2013, the NEMO Phase 2 tower has been successfully installed in the Capo Passero site, at a depth of 3500 m and 80 km off from the southern coast of Sicily. The unfurled tower is 450 m high; it is composed of 8 mechanical floors, for a total amount of 32 PMTs and various instruments for environmental measurements. The tower positioning is achieved by an acoustic system. The tower is continuously acquiring and transmitting all the measured signals to shore. Data reduction is completely performed in the Portopalo shore station by a dedicated computing facility connected to the persistent storage system at LNS, in Catania. Results from the last 9 months of acquisition will be presented. In particular, the analyzed optical rates, showing stable and low baseline values, are compatible with the contribution mainly of 40K light emission, with a small percentage of light bursts due to bioluminescence. These features reveal the optimal nature of the Capo Passero abyssal site to host a km3-sized Neutrino Telescope.

ELIMED a new concept of hadrontherapy with laser-driven beams

ELIMED (Medical Applications at Extreme Light Infrastructure) is a task-force originally born by an idea of ELI-Beams (Prague, CZ)and INFN-LNS (Italian Institute for Nuclear Physics of Catania, I) researchers. It now involves other groups interested in the possibility to design and develop a new generation of hadrontherapy facilities using laser-accelerated ion beams. ELIMED main goal is to perform proof-of-principle experiments aimed to demonstrate that laser-accelerated high-energy proton beams (up to 70 MeV in the first phase) can be potentially used for the specific case of ocular proton therapy. For this purpose new devices for beam handling and transport will be developed as well as new methods for radiobiology and dosimetry. The involvement of INFN-LNS group takes advantage of the well-established expertise in dosimetry measurements and Monte Carlo calculations for medical physics, which has been achieved in several years of eye tumor treatments in the CATANA proton therapy facility. Recently, in the framework of an INFN activity, they have also designed, fabricated, calibrated and experimentally tested at PALS laser laboratory (Cz) a Thomson Parabola ion spectrometer with a wide acceptance and able to characterize laser-driven proton beams up to 20 MeV.

Continuous monitoring of noise levels in the Gulf of Catania (Ionian Sea). Study of correlation with ship traffic

Acoustic noise levels were measured in the Gulf of Catania (Ionian Sea) from July 2012 to May 2013 by a low frequency (<1000Hz) hydrophone, installed on board the NEMO-SN1 multidisciplinary observatory. NEMO-SN1 is a cabled node of EMSO-ERIC, which was deployed at a water depth of 2100m, 25km off Catania. The study area is characterized by the proximity of mid-size harbors and shipping lanes. Measured noise levels were correlated with the passage of ships tracked with a dedicated AIS antenna. Noise power was measured in the frequency range between 10Hz and 1000Hz. Experimental data were compared with the results of a fast numerical model based on AIS data to evaluate the contribution of shipping noise in six consecutive 1/3 octave frequency bands, including the 1/3 octave frequency bands centered at 63Hz and 125Hz, indicated by the Marine Strategy Framework Directive (2008/56/EC).

The trigger and data acquisition for the NEMO-Phase 2 tower

In the framework of the Phase 2 of the NEMO neutrino telescope project, a tower with 32 optical modules is being operated since march 2013. A new scalable Trigger and Data Acquisition System (TriDAS) has been developed and extensively tested with the data from this tower. Adopting the all-data-to-shore concept, the NEMO TriDAS is optimized to deal with a continuous data-stream from off-shore to on-shore with a large bandwidth. The TriDAS consists of four computing layers: (i) data aggregation of isochronal hits from all optical modules; (ii) data filtering by means of concurrent trigger algorithms; (iii) composition of the filtered events into post-trigger files; (iv) persistent data storage. The TriDAS implementation is reported together with a review of dedicated on-line monitoring tools.

Long-term optical background measurements in the Capo Passero deep-sea site

In March 2013, the Nemo Phase-2 tower has been successfully installed at 100 km off-shore Capo Passero (Italy) and 3500 m depth. This 8-floor tower hosts 32 10-inch PMTs. Results from optical background measurements are presented. In particular, the analyzed rates show stable and low baseline values, compatible with the contribution of 40K light emission, with a small percentage of light bursts due to bioluminescence. All these features are a confirmation of the stability and good optical nature of the site.

Hybrid Configuration, Solid State-Tube, Revamps an Obsolete Tube Amplifier for the INFB K-800 Superconducting Cyclotron

An insertion of a solid state amplifier is substituting the obsolete first stage of a full tube RF power amplifier. The amplifier is based on two tube stages. The first, equipped by a tetrode, the RS1054, was being manufactured by Thales until some years ago. Some spare parts have been ordered but not enough to guarantee smooth cyclotron operation for the next few years. It was necessary to come up with a new solution. We were basically at a crossroad: replace the first stage with another tube still in production or change the technology from tube to solid state. A study, from market research to the technology point of view was carried out and the final decision was to use a solid state stage as an innovative solution for this kind of power vs frequency range of operation. The prototype of this hybrid amplifier has been in operation with our cyclotron since January 2015. The details of these decisions, the description of the modified amplifier (solid state – tube) and the successful results of this hybrid configuration will be shown in this presentation. RF AMPLIFIERS STORICAL OVERVIEW The RF power amplifiers are made by two tetrode stages driven by solid state commercial amplifiers. The drivers are class A, wideband, 50 dB gain and a maximum out power of 200 W. The RF power amplifier can deliver a maximum power of 75 kW, the total gain between 1 and 2 stage is about 30 dB. The first stage is wideband, based on the tetrode RS1054L by Thales, in groundcathode configuration, air-forced cooling. The second stage is a narrow band stage, common grid configured, based on 4CW100000E by CPI, water cooled. Figure 1: RF amplifiers and the 1 – 2 stages view. The three RF power amplifier cabinets with the internal view of the final stage are shown in Fig. 1. The tuning system for all the frequency range (15-50 MHz) is automatic. This amplification system was made, under technical specification by our Institute, at the end of 1980s. Since the commissioning of the Superconducting Cyclotron, 1994, the amplifiers have been operating, related to the RF power stages, without significant changes or upgrade. The robust and classical electrical design of the amplifiers has ensured, more or less, an uninterruptable operation, for the last 30 years. Figure 2 shows a simple block diagram of the RF system, with drivers and final amplifiers [1]. Figure 2: Block diagram of the RF system. The total gain between drivers and final amplifiers is approximately around 80 dB. The distribution is about 50 dB for the driver and 30 dB for the final amplifier. The final is divided between 14 and 16 dB respectively for the 1 and 2 stages. Despite the cost of the two tetrodes, in terms of spare parts, has greatly increased in the last decade, we decided to continue operating with this configuration. But some expedients was adopted. For example, we optimized the main parameters of the amplifiers, to reduce the maximum output power from 75 kW to 30 kW, enough for our cyclotron performance and as result, the average life span of the tetrodes was increased. We decided to refurbish the exhausted tetrodes, instead of buying new ones, reducing the cost by a third, and the reconstructed tetrode, can be considered like new. Unfortunately, this refurbished technique can be done only for the second stage, the 4CW100000E by CPI, while for the first stage, the RS1054L by Thales, it was not available. Apparently, the type, hardware and geometry of the tetrode itself made the rebuilding of the Thales tetrode almost impossible [2, 3]. ___________________________________________ * INFN-LNS † caruso@lns.infn.it Proceedings of Cyclotrons2016, Zurich, Switzerland WEB02 Cyclotron Technology ISBN 978-3-95450-167-0 263 C op yr ig ht