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Study for a coherent denoising in unmodeled reconstruction of gravitational wave strain
No full textI present a new method to remove detector noise from gravitationalwave (GW) interferometer data in the framework of unmodeled analyses, with special reference to coherent WaveBurst pipeline. The method introduces a pixel selection rule in the time-frequency representation of multidetector data to exclude noisy time-frequency components: this is performed multiplying each pixel by a weight function ranging from 0 to 1 and based on the coherence of the data among the detectors. Preliminary simulations indicate an improved suppression of noise with better reconstruction of both polarization components of detected GW signals
Enriching solar-cell front electrodes with Ag@MgO nanoparticles via physical deposition: A morphological and optical investigation
No full textCore-shell metal-oxide nanoparticles (NPs) have been extensively exploited in Perovskite solar cells (PSCs) to improve light harvesting and power conversion efficiency. Herein, we exploit a sequential physical method based on
nanocluster magnetron-sputtering techniques and MgO deposition to grow Ag NPs —embedded in an ultrathin MgO matrix— on top of a multilayered substrate, which acts as a front electrode in PSCs. The overall system morphology is investigated by Scanning Electron Microscopy (SEM) for different Ag@MgO coverages. The optical reflectance (R) and transmittance (T) spectra of both pristine and functionalized multilayer substrates are acquired for different substrate batches, showing remarkable differences. Data are analyzed by a specifically designed fitting procedure, which evaluates the contribution to R and T of each layer and extracts their complex refractive index ˜n, as well as their morphological properties, i.e. their thickness and roughness
Coarse-grained dynamics of ac-driven two-state systems
No full textMagnus expansion is used to identify effective Hamiltonians describing the coarse-grained dynamics of more complex problems. Here, we apply this method to a two-level system driven by an AC field. We derive Stark and Bloch-Siegert shifts of both diagonal and off-diagonal entries of the Hamiltonian as a result of coarse graining only
In silico validation of MCID tool for voxel dosimetry applied to 90Y radioembolization of liver malignancies
No full textThe aim of this work is validating the Monte Carlo Internal Dosimetry (MCID) tool for internal dosimetry, which allows personalized treatment planning starting from patient-specific images and direct Monte Carlo (MC) simulations. The absorbed dose for different computational phantoms, calculated with MC and with conventional MIRD methods at both organ and voxel level, were compared, obtaining differences of about 0.3% and within 3%, respectively, whereas differences increased (up to 14%) introducing tissue heterogeneities in phantoms. The absorbed dose of spheres with different radius (10 mm ≤ r ≤ 30 mm), calculated from MC code and from OLINDA/EXM was also compared, obtaining differences varying in the range 2–9% after correcting for partial volume effects (PVEs) from imaging. This work validated the MCID tool which allows the fast generation of input macros for MC simulations, starting from patient-specific images. It also shows the impact of tissue inhomogeneities on dosimetric results and their relevance for an accurate dosimetric plan
Optoelectronic characterization of NIR photodetectors based on Ge-on-Si microcrystals and microcrystal arrays
No full textWe report on the electro-optical characterization of Ge-on-Si microcrystals grown on Si patterned substrates, that can be used as absorbing elements for photodetection in the near-infrared (NIR). In such microstructures, light confinement effects, due to crystal faceting and pattern periodicity, enhance light absorption as compared to conventional epitaxial layers. By means of current-voltage and photoresponse measurements, performed on single microcrystals, we have investigated the optoelectronic properties of individual microcrystals and compared them with those of microcrystal arrays connected by a suspended graphene layer and those of a planar reference device. Microcrystal-based devices show enhanced photoresponse in the 1550–1700 nm spectral range, as compared with planar devices, in agreement with finite difference time domain (FDTD) simulations of light-trapping effects in such microstructures
Educational itineraries to promote Gender Equality in STEM
No full textTo promote Action-1 in the Italian PLS Project on Gender Equality in STEM, interdisciplinary teaching activities for High School students were developed in the 2019–2021 period. These activities were conceived in such a way that
the laboratory practice could be linked not only to technical or scientific contents but also to historical or sociological topics according to the Inquiry methodology.
During laboratory sessions, besides carrying out ordinary experimental activities on carefully selected topics, students had the chance to learn about the biography of
some female scientists whose research activities were related to these topics. Part of the activities was designed as an escape room process: students were guided through the maze by the relation existing between a female scientist and the relevant physics topic
Cosmic IT: A portable cosmic ray detecto
No full textCosmic ray detectors represent an interesting tool for the didactics of modern physics. The Cosmic it detector, designed by the INSULAB group, is a fully portable detector assembled inside a lightweight suitcase. It consists of three modules of plastic scintillator bars, which operate in coincidence. The electronics chain allows measuring the arrival time and the time over threshold (TOT) of the
signal generated by each scintillator module, which could be used to retrieve the deposited energy. In this paper we briefly present the basic structure of the detector along with the result of data taking on a private DA40ng light airplane
Interplay between surface and volume instabilities in heavy-ion collisions examined within mean-field extensions
No full textIn the transition from nuclear matter to finite nuclei, complex finitesize effects which characterise open systems arise, in relation with either the nuclear surface or the bulk. In addition, the non-equilibrium character of the process, typical of violent heavy-ion collisions (from Fermi energy to the intermediate-energy domain) adds up as well. The resulting dynamics is the combination of surface and volume unstable modes which trigger large-amplitude fluctuations. A rich variety of fragmentation patterns may emerge, ranging from collimated streams of nuclear
clusters to the split of a stretched nuclear complex into few large fragments. They imply different conditions of density and surface tension, and result in different
chronologies. Such phenomenology has been observed in experiments, but it is often difficult to recognise and disentangle the underlying types of instabilities. To
draw some example, two extremely deformed nuclear systems, produced below and above Fermi energy, are chosen and followed microscopically all along their evolution within the Boltzmann-Langevin One-Body approach
Isospin influence on the thermal characteristics in the reactions 78,86Kr + 40,48Ca at 10 AMeV
No full textIn this work, the preliminary results of the data analysis on the influence of the isospin on the thermometric characteristics, in the reactions 78Kr+40Ca and 86Kr+48Ca at 10 AMeV, will be shown. The thermal evaporation from compound nucleus and from the Quasi-Projectile have been studied within the thermometric method, based on the kinematic approach, in which the temperatures are extracted from the slope of the alpha particles energy spectra. Moreover, the values of the temperature, in fusion reactions, were measured with two different helium isotope ratio thermometers. In fusion-reactions higher temperature has been found for the system with higher neutron enrichment, independently of the nature of the method used for the determination of the temperature. This trend is confirmed by the comparison with the GEMINI++ statistical model. In contrast, for the QuasiProjectile the observed temperature is lower for the neutron rich system. These
results suggest that temperature is sensitive to the N/Z ratio
Population and decay of 12C states
No full textBy using the CHIMERA detector, we have measured the γ-ray
and α decay width of excited 12C states important for the carbon production in astrophysical environments. For the first time, we directly observed the γ-ray decay of the 9.64 MeV level. A γ-ray decay width larger than previous observations was observed for the Hoyle state. In order to explain this enhanced yield we investigated on the recently proposed population of an Efimov state at 7.458 MeV. The decay
characteristics of such level are inferred