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Use and reuse of spatial and quantitative data in archaeology: from 3D survey to serious game at Phaistos (Crete)
Get PDFThe article presents the results of a wider research carried out by a multidisciplinary group (archaeologists and engineers) of the University and the CNR-ISPC of Catania in the South-Western Quarter of the Minoan Palace of Phaistos (Crete). The article focuses on two digital survey campaigns carried out respectively in 2014, laser scanning, and 2019, Structure from Motion. Starting from the point cloud by laser scanner, the most recent, low cost and user-friendly photogrammetric tools (GoPro camera and software Agisoft Metashape) have been used during the 2019 campaign in order to update and to improve the previous dataset, which was used as a grid for georeferencing and scaling the new virtual model. Special attention was addressed to the comparison of the two datasets and to the reuse of the first one for georeferencing and scaling the second one. Furthermore, the research has been focused on the opportunity to exploit the obtained virtual model both for scientific purposes and for the outreach. The lack of accessibility of the South-Western Quarter of Phaistos Palace to the visitors attributes a special interest to this output. The virtual environment thus realized constituted an ideal starting point for the development of an educational fruition project based on a Serious Game approach. The cooperation of archaeologists and engineers in the development of the Phaistos game ensures a gaming experience not only pleasant but also provided with a strong educational profile
Il rilievo fotogrammetrico di Doclea
Get PDFThis paper deals with the practical application of photogrammetry in the study of the Roman city of Doclea in Montenegro, with particular reference to the use of Structure from Motion (SfM) techniques. Among the various research areas, archaeology of architecture and settlement archaeology make today an increasing use of photogrammetry for the in-field documentation of archaeological features. This method has an essential role in obtaining a reliable geometric survey that in turn forms the basis for the structural assessment of the architectural heritage thanks to consolidated methods such as archaeological stratigraphy and direct examination. In recent years, digital photogrammetry and the implementation of data processing technologies have made it possible to create three-dimensional models using images acquired through high-definition cameras. In addition to an accurate topographical survey, the aforementioned methods offer the opportunity to obtain a faithful representation of the real world, providing a basis for subsequent architectural and territorial studies. The use of drones equipped with cameras has proved to be particularly effective and capable of detecting large areas quickly and with good results. Due to its versatility and relative ease of use, photogrammetry could actually be deemed as an essential tool for the study and conservation of cultural heritage
Using time-of-flight information for PET, PET/CT and PET/MRI reconstruction
Get PDFThe timing resolution of PET detectors is rapidly improving thanks to new developments in detector design. As a result, the time of flight (TOF) measurement in PET systems is becoming more accurate as well. It has been shown that the TOF measurement supplies information that is not present in non-TOF PET emission data. Because TOF reduces the uncertainty associated with each measured
coincidence event, it improves the signal to noise ratio of the reconstructed images. For the same reason, the convergence of iterative reconstruction algorithms is faster and more uniform as well, which also benefits the quality of the reconstructed images. When the TOF resolution is sufficiently high, one can estimate from the
TOF-PET data not only the activity distribution, but also the attenuation coefficients. This enables attenuation correction in stand-alone PET scanners and the correction of the available attenuation map in hybrid PET systems. This correction may be valuable, because the CT-based attenuation maps in PET/CT and the MRbased attenuation maps in PET/MR can be degraded by motion, metal artefacts
and/or conversion errors. It is observed that for the estimation of the attenuation (or detector sensitivities) from TOF-PET emission data, accurate timing calibration
and scatter correction is mandatory. When the calibration and the scatter estimates are accurate, we find that attenuation correction based on the TOF-PET data themselves produces activity images that differ only up to a few percent from the activity images obtained with reference CT-based attenuation correction. With improving
TOF resolution, the power of the attenuation estimation algorithms increases, but the accuracy requirements for the timing calibration become more stringent as well
Large area picosecond photodetector (LAPPDTM) offers fast timing for nuclear physics and medical imaging
Get PDFThe availability of large-area, economically produced, microchannel plate (MCP) photodetectors with tens of picosecond timing resolution and millimeter level spatial resolution for single photoelectrons are enabling new techniques where fast timing facilitates critical benefits including: more efficient background rejection and high vertex resolution in large scale high energy and nuclear physics (HEP and NP) experiments, particle track directionality information, and precise track reconstruction, as well as separation of Cherenkov and scintillation light. LAPPDs are now being produced on a routine pilot production basis, and are available to be employed in high energy and nuclear physics, for commercial applications such as in detectors for mass spectrometers, neutron detection for scientific and homeland security (non-proliferation), and for medical imaging time-of-flight positron emission tomography (TOF-PET). In the following, we provide an update on target performance of routinely produced prototype LAPPDs, including the performance of one specific LAPPD which is being evaluated at UC Davis for potential TOF-PET application. Previously obtained preliminary TOF-PET test results, taken at Incom Inc. with an earlier LAPPD, are also discussed
Impact of the PDFs on the Z and W lineshapes at LHC
No full textThe parton distribution functions (PDFs) of the proton play a role in determining the lineshape of W and Z bosons produced at the LHC. In particular, the mode of the distribution of the gauge boson virtuality gets shifted with respect to the boson mass due to the dependence of the partonic luminosity on the boson virtuality itself. This shift contributes to the systematic uncertainty on the direct measurement of the boson mass. A detailed study of the shift and of its systematic uncertainty due to the limited knowledge of the PDFs is obtained using a tree-level model of W and Z boson production in proton-proton collisions at √s = 13 TeV. For the special case of W boson production, a Monte Carlo simulation is further used to validate the tree-level model and study the dependence of the shift on the transverse momentum of the W boson. The tree-level calculation is found to provide already a good description of the shift. The systematic uncertainty due to the PDFs is estimated to be below one MeV in the phase-space relevant for a future high-precision measurement of the W and Z boson masses at the LHC
Monitored beams for high-precision neutrino flux determination: The ENUBET project
No full textThe knowledge of initial flux, energy and flavour of current neutrino beams is currently the main limitation for a precise measurement of neutrino crosssections. The ENUBET ERC project (2016–2021) is studying a facility based on a narrow-band neutrino beam capable of constraining the neutrino flux normalization through the monitoring of the associated charged leptons in an instrumented decay tunnel. In particular, the identification of large-angle positrons from Ke3 decays
at single-particle level can reduce the νe flux uncertainty at the level of 1%. This setup would allow for an unprecedented measurement of the νe cross-section at
the GeV scale. Such an experimental input would be highly beneficial to reduce the budget of systematic uncertainties in the next long baseline oscillation projects (i.e., HyperK-DUNE). Furthermore, in narrow-band beams, the transverse position of the neutrino interaction at the detector can be exploited to determine a priori
with significant precision the neutrino energy spectrum without relying on the finalstate reconstruction
Geometrical models with Lorentz invariance violation and neutrino oscillations
No full textThe search for Lorentz Invariance Violation (LIV) is strictly connected with the high-energy structure of space-time. In the model we developed, LIV is introduced from modified dispersion relations (MDR) and a metric structure is preserved in Finsler geometry. The MDR corrections are represented by homogenous functions, introducing LIV sources of kinematical origin, without any new interaction. The Standard Model symmetries and the space isotropy are preserved. Every particle experiences its own limit velocity, as a function of its momentum,
and the modifications of the neutrino propagation equations induce additional corrections to the standard flavor oscillation pattern. Their impact on the oscillation probabilities is analyzed for many cases of phenomenological relevance
ttH¯ associated production in the all-jets final state with the CMS experiment
No full textThis work summarizes the state of the art of ttH¯ searches performed by the CMS experiment in the all-jets final state, namely the final state in which the Higgs boson decays to a b¯b pair and both the top quarks decay hadronically. New possible analysis strategies are also investigated, exploiting final states in the so-called boosted topology when at least one of the partons has a high Lorentz boost
and its decay products are reconstructed in the detector as a single, wide jet
Search for Dark Photons decaying to Lepton-Jets with the ATLAS detector at the LHC
No full textSeveral new physics models predict the existence of neutral particles with macroscopic lifetimes decaying into pairs of light leptons and hadrons with a jetlike structure (Lepton-Jets). This search uses data corresponding to an integrated luminosity of 36.1 fb−1 collected in proton-proton collisions at √s = 13 TeV recorded in 2015–2016 with the ATLAS detector at the Large Hadron Collider (LHC). The current results and the experimental challenges of these searches with the ATLAS
detector are presente
Search for neutrino and photon primary particles in the EeV energy range with the Pierre Auger Observatory
No full textThe Pierre Auger Observatory is the world’s largest cosmic-ray observatory. Updated results on the search for ultra-high energy photons and neutrinos in the EeV (1 EeV= 1018 eV) energy range are presented. Ultra-high energy photons can be produced either in the interactions with the cosmic microwave background or by the decay of hypothetical super-massive particles. Ultra-high energy neutrinos may arise from astrophysical sources due to hadronic interactions in the surrounding matter. The reached sensitivity is shown to be better (for photons) or comparable (for neutrinos) to other detectors