Search results for " fisica"

Influence of the grain-size on the energy tranfer between Ce, Cr3+ and Pr3+ in Y3Al2Ga3O12:Ce3+, Cr3+, Pr3+ nanophospors

2018

Phenol compounds as new materials for Electron Spin Resonance (ESR) dosimetry in clinical photon and electron beams

2015

In the last decades several research laboratories have shown an increasing interest aimed at extending the applicability of Electron Spin Resonance (ESR) dosimetry to radiotherapy with different types of radiation beams. ESR is a spectroscopic method for investigating the structure and dynamics of such paramagnetic species. Free radicals are known to be produced when a compound is irradiated with ionizing radiations. The concentration of radiation-induced free radicals is proportional to the energy released inside in the medium and this allows for dosimetric measurements through ESR technique which able to quantitatively determine the radical concentration.The use of alanine as a dosimetric…

Guano-related phosphate-rich minerals in European caves

2019

International audience; Guano is a typical deposit found in caves derived from the excretions of bats and in minor cases of birds. These organic deposits decompose and form a series of acid fluids and gases that can interact with the minerals, sediments, and rocks present in the cave. Over sixty phosphates are known and described from caves, but guano decay also often leads to the formation of nitrates and sulfates. In this study twenty-two European caves were investigated for their guano-related secondary minerals. Using various analytical techniques, seventeen phosphates, along with one sulfate (gypsum), were recognized as secondary products of guano decay. Among those minerals, some are …

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…

Terahertz Absorption change in Photosynthetic Reaction Center upon photoactivation

2012

Photosynthetic reaction center is a membrane protein which plays an important role in converting solar energy into chemical energy. Upon continuous illumination a charge separation occurs within the protein which is stable for several seconds [1]. The stability of this state is very important to protect the protein against the release of excess heat and an instable radical due to charge recombination. Absorption of terahertz radiation corresponds to the excitation of large vibrations in the protein and is thus suitable for studying its different dynamical states. Here we recorded terahertz absorption spectra of the dark and illuminated state of reaction centre from the purple membrane bacte…

Semiconductors: Growth and Characterization

2018

Semiconducting materials are widely used in several applications such as photonics, photovoltaics, electronics and thermoelectrics, because of their optical and electro-optical features. The fundamental and technological importance of these materials is due to the unique physical and chemical properties. Over the years, numerous methods have been developed for the synthesis of high efficient semiconductors. Besides, a variety of approach and characterization methods have been used to study the numerous and fascinating properties of the semiconducting materials. This book collects new developments about semiconductors, from the fundamental issues to the synthesis and applications. Special at…

CulnSe2/Zn(S,O,OH) junction on Mo foil by electrochemical and chemical route for photovoltaic applications

2014

Electrodeposition is a convenient technique for the development of low cost materials for photovoltaic (PV) device processing. Using a single step electrodeposition route, several groups have fabricated CIS (CuInSe) and CIGS (CuInGaSe) films [1]. One of the most important requirements for successful application of one-step electrodeposition film formation, is the ability to control composition of the deposited films and to develop polycrystalline microstructures with a low surface roughness and high sintered density. In this preliminary work, CIS films were produced by single bath electrodeposition finding the optimal conditions in order to achieve a dense film with high crystallinity and u…

PICOPHYTOPLANKTON DYNAMICS IN NOISY MARINE ENVIRONMENT

2012

We present a stochastic reaction-diffusion-taxis model to describe the picophytoplankton dynamics along a water column. The model, which is valid for poorly mixed waters, typical of the Mediterranean Sea, considers intraspecific competition of picophytoplankton for light and nutrients. Random fluctuations of environmental variables are taken into account by adding a source of multiplicative noise to the diffusion equation for the picophytoplankton biomass concentration, whose distribution along the water column shows a maximum at a certain depth. After converting our results into chlorophyll a concentrations, we compare theoretical distributions, obtained for different noise intensities, wi…

Self-cleaning ZnO/ITO/PET Bending Sensors

2022

The design of multifunctional materials is of pivotal importance for developing wearable biosensors. In particular, the advancement in self-cleaning materials suitable for bending sensors, i.e. devices able to track human body movements for healthcare monitoring [1], has raised much interest in recent pandemic times. Such technology can be facilitated by leveraging piezo-photocatalytic cleaning effects under visible light [2]. Herein, we show a new class of ZnO-based nanosheets (NSs) synthesized in aqueous solution (85 °C, 24 hours) onto seeded or seedless ITO/PET surfaces that couple sensing to photocatalysis. UV-vis and FT-IR spectroscopies show the typical absorption peaks of ZnO. A nano…