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
102428189
Observation of kaonic hydrogen atom X‐rays
120683548
Large-area low-pressure microstrip gas chambers for thermal neutron imaging
Abstract Thermal neutron imaging gas detectors using counting gas mixtures with gaseous neutron convertors (e.g. 3 He) suffer from inherent limitations in position and time-of-flight resolutions resulting from the long ranges of the released secondary ions in the counting gas and from parallax errors due to the necessary depth of the detector gas volume of >1 cm. In order to overcome these limitations a novel detector generation is presently being constructed utilizing composite neutron convertor foils ( 157 Gd or 6 Li overcoated with CsI) in combination with arrays of large-area microstrip and microdot gas chambers (MSGCs and MDOTs) which are operated in low-pressure, two-stage amplification mode and delivering unsurpassed gains. In this paper the optimization of MSGCs for low-pressure operation with 157 Gd convertors is discussed. The MSGCs are of technologically advanced, robust design, using 3 mm thick synthetic quartz substrates and two closely spaced electrode planes for true two-dimensional position readout. These metal planes are separated by a ∼3 μm thick SiO 2 /DLC double-layer deposited by means of plasma-enhanced CVD. The same fabrication technology is presently prepared for production of large-area MDOTs. The work shall be conducted in collaboration with nine teams from research institutes and industry.
120330344
High accuracy measurements of drift time in the streamer mode
Abstract A nitrogen laser focused to a 50 μm spot diameter with a minimum ionising energy deposit was used to scan a streamer tube. Results were obtained for the drift velocity and the spatial resolution. The resolution averaged, σ = ±25 μ m over the total drift length of 8 mm at atmospheric pressure. The charge multiplication region was also observed and could be separated into two regions, a region of low charge multiplication with increased drift velocity and an avalanche region with constant drift time.
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.
53630528
Simulation of VUV electroluminescence in micropattern gaseous detectors: the case of GEM and MHSP
Electroluminescence produced during avalanche development in gaseous avalanche detectors is a useful information for triggering, calorimetry and tracking in gaseous detectors. Noble gases present high electroluminescence yields, emitting mainly in the VUV region. The photons can provide signal readout if appropriate photosensors are used. Micropattern gaseous detectors are good candidates for signal amplification in high background and/or low rate experiments due to their high electroluminescence yields and radiopurity. In this work, the VUV light responses of the Gas Electron Multiplier and of the Micro-Hole & Strip Plate, working with pure xenon, are simulated and studied in detail using a new and versatile C++ toolkit. It is shown that the solid angle subtended by a photosensor placed below the microstructures depends on the operating conditions. The obtained absolute EL yields, determined for different gas pressures and as functions of the applied voltage, are compared with those determined experimentally.