120456193
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.
36324839
Searches for clustering in the time integrated skymap of the ANTARES neutrino telescope
This paper reports a search for spatial clustering of the arrival directions of high energy muon neutrinos detected by the ANTARES neutrino telescope. An improved two-point correlation method is used to study the autocorrelation of 3058 neutrino candidate events as well as cross-correlations with other classes of astrophysical objects: sources of high energy gamma rays, massive black holes and nearby galaxies. No significant deviations from the isotropic distribution of arrival directions expected from atmospheric backgrounds are observed.
55753733
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 3500 m depth about 80 km 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 13 km of water equivalent.
110859812
The Central Logic Board and its auxiliary boards for the optical module of the KM3Net detector
The KM3Net neutrino telescope will be composed of many optical modules, each of them containing 31 (3") photomultipliers, connected to a Central Logic Board. The Central Logic Board integrates Time to Digital Converters that measure Time over Threshold of the photomultipliers signals while White Rabbit is used for the optical modules time synchronization. Auxiliary boards have also been designed and built in order to test and extend the performance of the Central Logic Board. The Central Logic Board, as well as the auxiliary boards, will be presented by focusing on the design consideration, prototyping issues and tests.
118473267
A parameterisation of the flux and energy spectrum of single and multiple muons in the deep water or ice
Abstract Atmospheric muons play an important role in underwater/ice neutrino detectors. A parameterisation of the flux of single and multiple muon events, of their lateral distribution and energy spectrum is presented. The kinematics parameters were modelled starting from a full Monte Carlo simulation of the interaction of primary cosmic rays with atmospheric nuclei. The parametric formulas are valid for a vertical depth of 1.5–5 km w.e. and up to 85 ∘ for the zenith angle, and can be used as input for a fast simulation of atmospheric muons in underwater/ice detectors.
54839319
A search for time dependent neutrino emission from microquasars with the ANTARES telescope
Results are presented on a search for neutrino emission from a sample of six microquasars, based on the data collected by the ANTARES neutrino telescope between 2007 and 2010. By means of appropriate time cuts, the neutrino search has been restricted to the periods when the acceleration of relativistic jets was taking place at the microquasars under study. The time cuts have been chosen using the information from the X-ray telescopes RXTE/ASM and Swift/BAT, and, in one case, the gamma-ray telescope Fermi/LAT. No statistically significant excess has been observed, thus upper limits on the neutrino fluences have been derived and compared to the predictions by models. Constraints have been put on the ratio of proton to electron luminosity in the jets.
121746448
A comparison of the charge division and timing difference techniques in streamer mode
Abstract Resolutions of σ = ±3 mm and non-linearities of less than 5 mm have been measured over 99% of the length of 4 m streamer tubes by timing difference. In comparison charge division measurements give σ = ±1.4 mm at the centre of the tube decreasing to ±3mm at the ends of the tube, with non-linearities less than 5 mm. Both measurements were obtained with 35 m of coaxial cable between the detector and the active electronics.
102428189
Observation of kaonic hydrogen atom X‐rays
114549808
Development of gas micro-strip chambers for radiation detection and tracking at high rates
120956658
ON THE HIGH GAIN OPERATION OF LOW-PRESSURE MICRODOT GAS AVALANCHE CHAMBERS
Abstract Microdot avalanche chambers (MDOT) equipped with thin semitransparent Cr photocathodes, were characterized with UV photons at low gas pressure. Gains superior to 10 4 were reached with gas multiplication at the dots. In a mode where preamplification in the gas volume precedes the additional dot multiplication, gains superior to 10 6 were measured at 30–60 torr of propane. The fast amplification mechanism results in narrow high amplitude pulses with 2–3 ns rise time, visible with no further electronic amplification means. We present here our preliminary results and briefly discuss potential applications.
121174846
First experimental results from a microdot gas avalanche detector integrated onto a silicon wafer
First results on the voltage dependence of the gas gain of a microdot detector are presented. No variation of the gas gain with rate is observed up to a measured maximum rate of 4 x lo3 X-rays/mm*/s. Some possible applications of this detector are discussed.