Search results for " CAM"

Signal to Noise Ratio of Silicon Photomultipliers measured in the Continuous Wave Regime

2014

We performed a Signal to Noise Ratio characterization, in the continuous wave regime, at different bias voltages, frequencies and temperatures, on a novel class of silicon photomultipliers fabricated in planar technology on silicon p-type substrate. Signal to Noise Ratio has been measured as the ratio of the photogenerated current, filtered and averaged by a lock-in amplifier, and the Root Mean Square deviation of the overall current flowing to the device. The measured noise takes into account the shot noise, resulting from the photocurrent and the dark current. We have also performed a comparison between our SiPMs and a photomultiplier tube in terms of Signal to Noise Ratio, as a function …

PARAMETRIC SELF-TRAPPING OF OPTICAL BEAMS VIA RANDOM QUASI PHASE MATCHING IN LITHIUM TANTALATE WAVEGUIDE

2011

We report on experimental evidence of parametric spatial solitons in a lithium tantalate waveguide with randomized periodic ferroelectric poling. Two-color self-focusing via quadratic cascading overcomes the diffractive nature of both fundamental and frequency-doubled beams.

Z-Scan theory for thin film measurements: Validation of a model beyond the standard approach using ITO and HfO2

2023

The Z-Scan technique is an easy and widespread approach to evaluate the nonlinear optical coefficient of materials. However, the evaluation of the same coefficients for thin films requires complex experimental setups that allow to remove the contributions of the substrate. Here, we propose a simple, yet effective, theoretical approach that allows to include the substrate contribution to the focusing effect when scanning along the propagation axis. The proposed method therefore removes the need of complex experimental setups and paves the way for a simpler retrieval of optical properties of complex nanostructures.

A Novel Technique for Monitoring the W-Beam Guardrails

2014

The paper addresses the problem of the measurement of guardrails’ deformations by means automatic analysis of optical images. The technique is founded on the analysis of high-resolution photos, obtained by means of 3D camera installed into a data vehicle. The novel methodology has been used to calculate the longitudinal safety barrier deformations for one W-beam guardrails installed along a rural road in Italy. The procedure has shown that digital image analysis can be used with the aim to monitoring guardrails and, therefore, for guarantee reasonable levels of protection against serious ran-off-road crashes.

Una incursione fotografica ‘sul campo’ e l’antropologia ‘fuori campo’

2014

Determining the nuclear neutron distribution from Coherent Elastic neutrino-Nucleus Scattering: current results and future prospects

2020

Coherent Elastic neutrino-Nucleus Scattering (CEνNS), a process recently measured for the first time at ORNL’s Spallation Neutron Source, is directly sensitive to the weak form factor of the nucleus. The European Spallation Source (ESS), presently under construction, will generate the most intense pulsed neutrino flux suitable for the detection of CEνNS. In this paper we quantify its potential to determine the root mean square radius of the point-neutron distribution, for a variety of target nuclei and a suite of detectors. To put our results in context we also derive, for the first time, a constraint on this parameter from the analysis of the energy and timing data of the CsI detector at t…

Design of a High-Efficiency Ka-Band TWT Power Amplifier for Radar Applications

2022

The design of a high-efficiency Traveling Wave Tube (TWT) based on a non-conventional folded waveguide slow-wave structure (FW-SWS) operating over 34-36 GHz for naval and ground Ka-band radars is presented. The ridge vane-loaded FW structure allows a good compromise between high interaction impedance and wide bandwidth along with a low weight required for aircraft radar applications and a simple planar manufacturing process structure. Small signal simulations are performed with a custom interaction impedance evaluation program. The CST suite 2021 3D electromagnetic simulation code is used for the prediction of the dispersion diagram. Starting from a sensitivity analysis of the folded wavegu…

Search for neutral Higgs bosons decaying into four taus at LEP2

2010

A search for the production and non-standard decay of a Higgs boson, h, into four taus through intermediate pseudoscalars, a, is conducted on 683 pb-1 of data collected by the ALEPH experiment at centre-of-mass energies from 183 to 209 GeV. No excess of events above background is observed, and exclusion limits are placed on the combined production cross section times branching ratio, β2 = σ(e+e -→Zh)/σSM(e+e-→Zh) ×B(h→aa)×B(a→τ+τ-) 2. For mh 1 is excluded at the 95% confidence level.

First tests of the applicability of gamma-ray imaging for background discrimination in time-of-flight neutron capture measurements

2015

In this work we explore for the first time the applicability of using $\gamma$-ray imaging in neutron capture measurements to identify and suppress spatially localized background. For this aim, a pinhole gamma camera is assembled, tested and characterized in terms of energy and spatial performance. It consists of a monolithic CeBr$_3$ scintillating crystal coupled to a position-sensitive photomultiplier and readout through an integrated circuit AMIC2GR. The pinhole collimator is a massive carven block of lead. A series of dedicated measurements with calibrated sources and with a neutron beam incident on a $^{197}$Au sample have been carried out at n_TOF, achieving an enhancement of a factor…

Pues que sois del Sol Divino Madre, y del hombre Señora, amparadnos, bella Aurora, Virgen Santa del Molino

Com a tít. la primera estrofa, donat que del tít. sols es pot llegir o intuir part: "[...] nuestra Señora del Molino [...] venerada en el lugar de Santa Eulalia, Reyno de Aragon" El full orlat Grav. xil. enmarcat de la Mare de Déu, flanquejat per gerros amb flors Text del goig a tres col. separades per filets