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.
3568406
SEARCH FOR A CORRELATION BETWEEN ANTARES NEUTRINOS AND PIERRE AUGER OBSERVATORY UHECRs ARRIVAL DIRECTIONS
This paper presents a search for correlation in the arrival directions of 2190 neutrino candidate events detected in 2007-2008 by the ANTARES telescope, and 69 ultra-high energy cosmic rays (UHECRs) observed by the Pierre Auger Observatory between January 1st 2004 and December 31st 2009. No significant correlation was found. The corresponding 90% C.L. upper limit on the neutrino flux from all 69 sources, assuming an equal flux from all of them and for $E^{-2}$ energy spectrum, is 4.99$\times10{^{-8}}$ GeV cm$^{-2}$ s$^{-1}$.
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.
55338525
Recent achievements of the NEMO project
The status of the activities towards the realization of a km Cherenkov neutrino detector carried out by the NEMO Collaboration is described. The realization of a Phase-1 project, which is under way, will validate the proposed technologies for the realization of the km detector on a Test Site at 2000m depth. The realization of a new infrastructure on the candidate site (Phase-2 project) will provide the possibility to test detector components at 3500m depth. r 2008 Elsevier B.V. All rights reserved. PACS: 95.55.Vj; 95.85.Ry
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.
122398469
Doppler-shifted nuclear gamma rays following stopped K− capture in aluminium
Abstract The Doppler broadened 26 Mg * decay gamma peak hasma peak has been observed in coincidence with stopped kaons in an Al target. The results are compared with predictions based on single-nucleon absorption of the kaon.
120592230
A multiterm Boltzmann analysis of drift velocity, diffusion, gain and magnetic-field effects in argon-methane-water-vapour mixtures
Abstract The effect of adding water vapour to argon-methane mixtures used in TPC-type detectors is investigated using the exact multiterm Boltzmann expansion. The transverse and longitudinal diffusion coefficients and the drift velocity are calculated with an accuracy of ± 3, ± 2 and ± 1% respectively. The calculations are extended into the avalanche region and compared to avalanche gain measurements. The effect of misalignment of the electric and magnetic fields on the drift direction is also investigated.
121172334
Measurement of strong interaction effects in kaonic atoms
Abstract X-rays produced by kaons stopping in targets of O, Mg, Al, Si, S, Co, Ni, Cu, Ag, Cd, In and Sn have been observed. The shifts, widths and yields of the last observed mesic X-ray due to the effects of the strong interaction have been measured. The results are compared with optical-model predictions.
120826173
Observation of UV photons with a microdot chamber
Microdot gas chambers have been developed which are suitable for imaging x-rays or minimum ionising particles. The problems encountered in the extension of the operating region to gains of over 10000 are described. Results obtained from single photo electron extraction by a UV source from the aluminium drift cathode are presented at avalanche gains of up to 30000. A solution is proposed, which will allow the imaging of single UV photons with less than 60 microns precision in both x and y directions simultaneously, using a detector integrated on to a quartz substrate.
56301921
High rate behavior and discharge limits in micro-pattern detectors
Abstract We present and discuss a set of systematic measurements, carried out with gaseous proportional micro-pattern detectors, in order to assess their maximum gain when irradiated with high-rate soft X-rays and heavily ionizing alpha particles. The inventory of detectors tested includes: micro-strips, micromegas, micro-dot, gas electron multiplier, CAT (compteur a trous), trench (or groove), micro-CAT (or WELL) detectors, as well as systems with two elements of gaseous amplification in cascade. We confirm the general trend of all single-stage detectors to follow Raether's criterion, i.e. a spontaneous transition from avalanche to streamer, followed by a discharge, when the avalanche size reaches a value of a few 10 7 ; a noticeable exception is the micro-dot counter holding more than 10 8 . In multiple structures, where the gain is shared between two devices in cascade, the maximum overall gain under irradiation is increased by at least one order of magnitude; we speculate this to be a consequence of a voltage dependence of Raether's limit, larger for low operating potentials. Our conclusion is that only multiple devices can guarantee a sufficient margin of reliability for operation in harsh LHC running conditions.