Search results for "photo"

Signal to noise ratio measurements of silicon photomultipliers

2014

We report on our signal to noise ratio (SNR) measurements carried out, in the continuous wave regime, on a novel class of silicon photomultipliers (SiPMs) fabricated in planar technology on silicon p-type substrate. SiPMs are large area detectors consisting of a parallel array of Geiger Mode APDs with individual integrated quenching resistors. Each photodiode is an independent photon counting microcell and is connected to a common analog output to produce a summation signal proportional to the number of detected photons [1], [2]. SNR of SiPMs is expressed by the ratio of the SiPM average signal current and the RMS deviation of the overall current (i.e., the overall shot noise current). The …

Direct photon elliptic flow in Pb–Pb collisions √sNN = 2.76 TeV

2019

The elliptic flow of inclusive and direct photons was measured at mid-rapidity in two centrality classes 0–20% and 20–40% in Pb–Pb collisions at √sNN = 2.76 TeV by ALICE. Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the detector material with the e+e− pairs reconstructed in the central tracking system. The results of the two methods were combined and the direct-photon elliptic flow was extracted in the transverse momentum range 0.9 < pT < 6.2 GeV/c. A comparison to RHIC data shows a similar magnitude of the measured directphoton elliptic flow. Hydrodynamic and transport model calculations are systematically lower than the data, but …

Study of scintillation light collection, production and propagation in a 4 tonne dual-phase LArTPC

2020

The $3 \times 1 \times 1$ m$^3$ demonstrator is a dual phase liquid argon time projection chamber that has recorded cosmic rays events in 2017 at CERN. The light signal in these detectors is crucial to provide precise timing capabilities. The performances of the photon detection system, composed of five PMTs, are discussed. The collected scintillation and electroluminescence light created by passing particles has been studied in various detector conditions. In particular, the scintillation light production and propagation processes have been analyzed and compared to simulations, improving the understanding of some liquid argon properties.

Experimental generalized quantum suppression law in Sylvester interferometers

2017

Photonic interference is a key quantum resource for optical quantum computation, and in particular for so-called boson sampling machines. In interferometers with certain symmetries, genuine multiphoton quantum interference effectively suppresses certain sets of events, as in the original Hong-Ou-Mandel effect. Recently, it was shown that some classical and semi-classical models could be ruled out by identifying such suppressions in Fourier interferometers. Here we propose a suppression law suitable for random-input experiments in multimode Sylvester interferometers, and verify it experimentally using 4- and 8-mode integrated interferometers. The observed suppression is stronger than what is…

Majorana parameters of the interacting boson model of nuclear structure and their implication for 0νββ decay

2021

Nucleon dissociation and incoherent J/ψ photoproduction on nuclei in ion ultraperipheral collisions at the CERN Large Hadron Collider

2019

Using the general notion of cross section fluctuations in hadron-nucleus scattering at high energies, we derive an expression for the cross section of incoherent J / ψ photoproduction on heavy nuclei d σ γ A → J / ψ Y / d t , which includes both elastic d σ γ p → J / ψ p / d t and proton-dissociation d σ γ p → J / ψ Y / d t photoproduction on target nucleons. We find that, with good accuracy, d σ γ A → J / ψ Y / d t can be expressed as a product of the sum of the d σ γ p → J / ψ p / d t and d σ γ p → J / ψ Y / d t cross sections, which have been measured at HERA, and the common nuclear shadowing factor, which is calculated using the leading twist nuclear shadowing model. Our prediction for …

Effect of the compatibilization on the photooxidation of a PA6/LDPE blend and their clay nanocomposites

2014

Photooxidation and stabilization of a solar cell encapsulating crosslinked EVA

2014

PHOTOOXIDATION BEHAVIOR OF POLYPROPYLENE NANOCOMPOSITES WITH MODIFIED HALLOYSITE

2017

The photooxidation behaviour of polymer nanocomposites depends on the photooxidation of the matrix, but also on the possible interactions with the nanoparticles. In this work, the effect of halloysite modified nanoparticles on the photooxidation of a polypropylene matrix has been investigated.

Identification, characterization and analysis of expression of genes encoding arylalkylamine N-acetyltransferases in the pea aphidAcyrthosiphon pisum

2013

Most organisms exhibit some kind of rhythmicity in their behaviour and/or physiology as an adaptation to the cyclical movements of the Earth. In addition to circadian rhythms, many organisms have an annual rhythmicity in certain activities, such as reproduction, migration or induction of diapause. Current knowledge of the molecular basis controlling seasonal rhythmicity, especially in insects, is scarce. One element that seems to play an essential role in the maintenance of both circadian and seasonal rhythms in vertebrates is the hormone melatonin. In vertebrates, the limiting enzyme in its synthesis is the arylalkylamine N-acetyltransferase (AANAT). Melatonin is also present in insects bu…