54 research outputs found
Wide energy range trigger and development of new electronics for ICARUS LAr-TPC
No full textThe ICARUS-T600 detector, with its 470 tons of active mass, is the largest Liquid Argon TPC (LAr-TPC) ever built, and is now currently operating in the LNGS underground laboratory, detecting cosmic rays events after 3 years of data taking with the CERN Neutrinos to Gran Sasso beam. Its excellent calorimetric resolution and topol- ogy reconstruction capabilities permit a wide physics program, which goes from nucleon decay to the study of the oscillation of the neutrinos from the CNGS beam. The events collected differ both for energy deposition (ranging from tens of MeV to tens of GeV) and for topology. To get a fully-efficient detection of the interesting events it is thus necessary to exploit all available sources in the trigger system: the scintillation light, the charge signal on wires and timing information (for beam-related events).
For the 2010-2013 data taking a primary trigger, based on the signal from the photomultipliers placed inside the detector, has been set up. To enhance the efficiency of this setup for CNGS neutrino events, a particular effort has been addressed to the development of a time synchronization with the spill extraction, which allowed to reduce the trigger threshold in coincidence with the neutrino arrival time. To check the PMT efficiency for the CNGS events, an alternative minimum biasing trigger has been also developed, which is based on the time synchronization as well as on the analysis of the charge deposition on the TPC wires. A full efficiency and a rejection of more than 103 have been reached with this trigger.
To further increase the PMT trigger efficiency on non beam related events, an hit finding algorithm has been implemented in a hardware device, and is now taking data in steady condition. First results of this recently installed system, have shown an increase of the overall trigger efficiency on the sub-GeV region, which is of particular interest in view of the study of nucleon decay as well as on the low energy tail of the atmospheric neutrons.
Finally ICARUS solved the anomaly reported by the OPERA collaborations on the superluminar neutrino velocity, by performing a high precision measurement of the neutrino time of flight from CERN to LNGS, resulting in perfectly agreement, within the experimental resolution, with the light velocity
Strong Measurements Give a Better Direct Measurement of the Quantum Wave Function
No full textWeak measurements have thus far been considered instrumental in the so-called direct measurement of the quantum wave function [J. S. Lundeen, Nature (London) 474, 188 (2011).]. Here we show that a direct measurement of the wave function can be obtained by using measurements of arbitrary strength. In particular, in the case of strong measurements, i.e., those in which the coupling between the system and the measuring apparatus is maximum, we compared the precision and the accuracy of the two methods, by showing that strong measurements outperform weak measurements in both for arbitrary quantum states in most cases. We also give the exact expression of the difference between the original and reconstructed wave function obtained by the weak measurement approach; this will allow one to define the range of applicability of such a method
Physics for gifted children: A laboratory experience for primary- and middle-school students.
No full textIn the framework of Education to Talent 2, an initiative addressing the subject of gifted children and their problems in adapting to the educational system, a one-day physics laboratory for gifted primary- and middle-school students was organized. Aspects like fast pace, understanding of concepts, and inquiry, crucial ingredients when creating stimulating learning environments for gifted children, were considered in the design of the laboratory activities. This communication gives a detailed description and evaluation of the experiences encountered in the laboratory unit on electricity and discusses the critical points in view of an extension of the approach in regular classrooms
Spatial-mode-demultiplexing for enhanced intensity and distance measurement
No full textSpatial-mode demultiplexing (SPADE) has recently been adopted to measure the
separation in the transverse plane between two incoherent point-like sources.
It has been argued that this approach may yield extraordinary performances in
the photon-counting regime. Here, we explore SPADE as a tool for precision
measurements in the regime of bright, incoherent sources. First we analyse the
general problem of estimating the second moments of the source's intensity
distribution, for an extended incoherent source of any shape. Second, we
present an experimental application of SPADE to the case of two point-like,
bright sources. We demonstrate the use of this setup for the estimation of the
transverse separation and for the estimation of their relative intensity.Comment: Comments are welcom
Qubit4Sync: a qubit-based synchronization system for quantum key distribution
No full textQubit4Sync is a synchronization method for quantum key distribution which uses the same qubits exchanged during the protocol; in the same spirit of classical communication protocols reling on clock recovery methods that uses the data stream itself
Experimental single photon exchange along a space link of 7000 km
No full textExtending the single photon transmission distance is a basic requirement for the implementation of quantum communication on a global scale. In this work we report the single photon exchange from a medium Earth orbit satellite (MEO) at more than 7000 km of slanted distance to the ground station at the Matera Laser Ranging Observatory. The single photon transmitter was realized by exploiting the corner cube retro-reflectors mounted on the LAGEOS-2 satellite. Long duration of data collection is possible with such altitude, up to 43 minutes in a single passage. The mean number of photons per pulse (µsat) has been limited to 1 for 200 seconds, resulting in an average detection rate of 3.0 cps and a signal to noise ratio of 1.5. The feasibility of single photon exchange from MEO satellites paves the way to tests of Quantum Mechanics in moving frames and to global Quantum Information
3D printing of normal and pathologic tricuspid valves from transthoracic 3D echocardiography data sets
No full textAIMS: To explore the feasibility of using transthoracic 3D echocardiography (3DTTE) data to generate 3D patient-specific models of tricuspid valve (TV).
METHODS AND RESULTS: Multi-beat 3D data sets of the TV (32 vol/s) were acquired in five subjects with various TV morphologies from the apical approach and analysed offline with custom-made software. Coordinates representing the annulus and the leaflets were imported into MeshLab (Visual Computing Lab ISTICNR) to develop solid models to be converted to stereolithographic file format and 3D print. Measurements of the TV annulus antero-posterior (AP) and medio-lateral (ML) diameters, perimeter (P), and TV tenting height (H) and volume (V) obtained from the 3D echo data set were compared with those performed on the 3D models using a caliper, a syringe and a millimeter tape. Antero-posterior (4.2 ± 0.2 cm vs. 4.2 ± 0 cm), ML (3.7 ± 0.2 cm vs. 3.6 ± 0.1 cm), P (12.6 ± 0.2 cm vs. 12.7 ± 0.1 cm), H (11.2 ± 2.1 mm vs. 10.8 ± 2.1 mm) and V (3.0 ± 0.6 ml vs. 2.8 ± 1.4 ml) were similar (P = NS for all) when measured on the 3D data set and the printed model. The two sets of measurements were highly correlated (r = 0.991). The mean absolute error (2D - 3D) for AP, ML, P and tenting H was 0.7 ± 0.3 mm, indicating accuracy of the 3D model of <1 mm.
CONCLUSION: Three-dimensional printing of the TV from 3DTTE data is feasible with highly conserved fidelity. This technique has the potential for rapid integration into clinical practice to assist with decision-making, surgical planning, and teaching
Interference at the Single Photon Level Along Satellite-Ground Channels
No full textQuantum interference arising from the superposition of states is striking evidence of the validity of
quantum mechanics, confirmed in many experiments and also exploited in applications. However, as for
any scientific theory, quantum mechanics is valid within the limits in which it has been experimentally
verified. In order to extend such limits, it is necessary to observe quantum interference in unexplored
conditions such as moving terminals at large distances in space. Here, we experimentally demonstrate
single photon interference at a ground station due to the coherent superposition of two temporal modes
reflected by a rapidly moving satellite a thousand kilometers away. The relative speed of the satellite
induces a varying modulation in the interference pattern. The measurement of the satellite distance in real
time by laser ranging allows us to precisely predict the instantaneous value of the interference phase. We
then observed the interference patterns with a visibility up to 67% with three different satellites and with a
path length up to 5000 km. Our results attest to the viability of photon temporal modes for fundamental
tests of physics and quantum communication in space
Experimental Satellite Quantum Communications
No full textQuantum communication (QC), namely, the faithful transmission of generic quantum states, is a key ingredient of quantum information science. Here we demonstrate QC with polarization encoding from space to ground by exploiting satellite corner cube retroreflectors as quantum transmitters in orbit and the Matera Laser Ranging Observatory of the Italian Space Agency in Matera, Italy, as a quantum receiver. The quantum bit error ratio (QBER) has been kept steadily low to a level suitable for several quantum information protocols, as the violation of Bell inequalities or quantum key distribution (QKD). Indeed, by taking data from different satellites, we demonstrate an average value of QBER = 4.6% for a total link duration of 85 s. The mean photon number per pulse μsat leaving the satellites was estimated to be of the order of one. In addition, we propose a fully operational satellite QKD system by exploiting our communication scheme with orbiting retroreflectors equipped with a modulator, a very compact payload. Our scheme paves the way toward the implementation of a QC worldwide network leveraging existing receivers
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