435 research outputs found
Thermal physical modelling for eye injury prevention in high environmental temperature workplaces
No full textBackground: High temperatures are encountered in many workplaces as iron and
steel foundries, nonferrous foundries, brick-firing and ceramic plants, glass
products facilities, rubber products factories, electrical utilities, bakeries, laundries,
chemical plants, mining sites, smelters, and steam tunnels. Workers in these
industries can suffer from various diseases and injuries, including eye problems,
due to exposure to high temperatures and handling of heavy materials.
Methods: This study aims to analyse the pressure inside the eye's anterior
chamber, known as Intraocular Pressure (IOP), and its relation to the biomechanical
properties of the cornea, specifically concerning the cornea's temperature. The
approach used is based on the first law of thermodynamics. The results
demonstrate the relationship between the ocular anterior chamber's temperature
and the cornea's biomechanical properties.
Results: The IOP measures the cornea's elasticity and its refractive properties
concerning its temperature. We develop a study to investigate how the cornea's
elastic work, or potential energy, changes with temperature. Our findings indicate
that as the temperature rises, the work done by the cornea decreases. The cornea's
temperature is affected by both the surrounding environment and the temperature
of the fluid in the front part of the eye. This suggests a link between the work done
by the cornea against the pressure of the fluid in the front of the eye and the fluid.
Accordingly, there is also a correlation between the thickness of the cornea and the
IOP, and our modelling method enables us to establish this relationship.
Conclusions: The first law of thermodynamics is used to determine the work done
by the anterior chamber against the internal cornea wall. Temperature regulates
the aqueous humour's secretion, excretion, and flow dynamics, impacting IOP and
related diseases. This has implications for developing preventive systems to protect
workers' eyes from injury
High-rate performance of the MWPCs for the LHCb muon system
No full textThe high-rate performance of a multiwire proportional chamber of the LHCb muon detector was tested. The chamber, equipped with the final front-end electronics, was tested using a similar to 100GeV muon beam superimposed on a 662 keV gamma flux of variable intensity produced by the Cs-137 radioactive source of the CERN Gamma Irradiation Facility (GIF). No significant variation in the muon detection efficiency or in the time response of the chamber was observed at the highest gamma rate. (C) 2008 Elsevier B.V. All rights reserved
High radiation tests of the MWPCs for the LHCb Muon System
No full textThe MultiWire Proportional Chambers (MWPCs) for the LHCb Muon Detector were subjected to an ageing test, performed in the high-radiation environment of the Calliope Gamma Facility of the ENEA-Casaccia Research Centre. The test showed that the MWPCs can safely operate for many years in a high intensity particle flux. An additional test, performed with the CERN Gamma Irradiation Facility (GIF), confirmed these conclusions. (c) 2008 Elsevier B.V. All rights reserved
Crilin: A Semi-Homogeneous Calorimeter for a Future Muon Collider
No full textCalorimeters, as other detectors, have to face the increasing performance demands of the new energy frontier experiments. For a future Muon Collider the main challenge is given by the Beam Induced Background that may pose limitations to the physics performance. However, it is possible to reduce the BIB impact by exploiting some of its characteristics by ensuring high granularity, excellent timing, longitudinal segmentation and good energy resolution. The proposed design, the Crilin calorimeter, is an alternative semi-homogeneous ECAL barrel for the Muon Collider based on Lead Fluoride Crystals (PbF (Formula presented.)) with a surface-mount UV-extended Silicon Photomultipliers (SiPMs) readout with an optimized design for a future Muon Collider
PROGETTO E(') INTERPRETAZIONE
No full textOgni progetto di architettura è una storia, scritta da più attori, il cui esito dipende da mille fattori, a volte ingovernabili. La sua buona riuscita, quindi, è legata al verificarsi di alcune congiunture, indotte o fortuite, che ne determinano il successo o il fallimento, anche dopo molto tempo dalla realizzazione.
In questo libro si racconta una storia con l’happy end, nata dal basso, dall’intuizione di un gruppo di studenti appassionati, guidati da docenti aperti e lungimiranti, che li hanno saputi accompagnare lungo un percorso impegnativo e difficile, fino al raggiungimento dell’obiettivo che si erano prefissati. Scrivendo un racconto che narra un’esperienza al tempo stesso didattica e professionale, astratta (come deve essere un’esercitazione accademica), ma contemporaneamente concreta (come è sempre un qualunque processo progettuale).
Un progetto di architettura può nascere anche così, senza una committenza, o meglio con un’auto-committenza che definisce un programma, e poi cerca le risorse per attuarlo e portarlo a compimento: anche questa è ricerca progettuale
The calorimeter project for the Mu2e experiment
No full textThe Mu2e experiment at Fermilab aims to measure the charged lepton flavor violating neutrinoless conversion of a negative muon into an electron. The conversion results in a monochromatic electron with an energy slightly below the rest mass of the muon (104.97 MeV). We expect to set a limit of ∼ 6×10^(−17) at 90% CL in three years of running, using an intense and clean pulsed μ^− beam providing ∼10^(18) stopped muons on target in three years of running. The experiment performs a strong suppression of potential background by gating off the prompts and performing precise momentum determination in conjunction with an highly efficient cosmic veto. The calorimeter should confirm that the candidates reconstructed by the tracker system are indeed conversion electrons and provide an independent trigger (or event reduction filter) for the experiment. It should also provide standalone muon to electron rejection. Moreover, it must be able to keep functionality in a high radiation dose environment inside a 10^(−4)_(torr) vacuum enclosure and in a presence of 1 T axial magnetic field. In order to accomplish all these tasks, a LYSO crystals calorimeter has been chosen. We show the proposed design and the experimental results obtained by exposing a small size calorimeter prototype to a tagged photon beam from 40 to 300 MeV at the A2 photon facility of the Mainz Microton (MAMI), Germany
Research and Development Status for an Innovative Crystal Calorimeter for the Future Muon Collider
No full textAccurate measurements of physical processes in high energy frontier experiments demand exceptional spatial, temporal, and energy precision to discern the physics behind high-energy particle jets. Calorimeters, like other detection systems, must be able to meet these increasingly challenging performance requirements. In the prospective TeV-scale Muon Collider, the primary hurdle in designing detectors and devising event reconstruction algorithms is the challenge posed by Beam-Induced Background (BIB). Nevertheless, it is conceivable to mitigate the impact of BIB on the Muon Collider’s calorimeter by capitalizing on certain characteristics and ensuring key features such as high granularity, precise timing, longitudinal segmentation, and superior energy resolution. This is what the here described Research and Development is trying to achieve with an innovative semi-homogeneous electromagnetic calorimeter constructed from stackable and interchangeable modules composed of lead fluoride crystals (PbF2). These modules are equipped with surface-mount UV-extended Silicon Photomultipliers (SiPMs) and are collectively referred to as the Crilin calorimeter (CRystal calorImeter with Longitudinal INformation). The challenge lies in making sure this calorimeter can operate effectively within an extremely harsh radiation environment, enduring an annual neutron flux of and a total ionizing dose (TID) of 10 kGy. In this article, the radiation tolerance measured in several irradiation campaigns is discussed, and the timing performances during a test beam at CERN-H2 with 120-GeV electrons. Additionally, a description of the latest prototype, Proto-1, is provided together with the results of the latest low-energy beam test at the LNF beam test facility (BTF) with 450 MeV electrons
Research and Development Status for an Innovative Crystal Calorimeter for the Future Muon Collider
No full textAccurate measurements of physical processes in high energy frontier experiments demand exceptional spatial, temporal, and energy precision to discern the physics behind high-energy particle jets. Calorimeters, like other detection systems, must be able to meet these increasingly challenging performance requirements. In the prospective TeV-scale Muon Collider, the primary hurdle in designing detectors and devising event reconstruction algorithms is the challenge posed by Beam-Induced Background (BIB). Nevertheless, it is conceivable to mitigate the impact of BIB on the Muon Collider's calorimeter by capitalizing on certain characteristics and ensuring key features such as high granularity, precise timing, longitudinal segmentation, and superior energy resolution. This is what the here described Research and Development is trying to achieve with an innovative semi-homogeneous electromagnetic calorimeter constructed from stackable and interchangeable modules composed of lead fluoride crystals (PbF2). These modules are equipped with surface-mount UV-extended Silicon Photomultipliers (SiPMs) and are collectively referred to as the Crilin calorimeter (CRystal calorImeter with Longitudinal INformation). The challenge lies in making sure this calorimeter can operate effectively within an extremely harsh radiation environment, enduring an annual neutron flux of 1014 n1MeV/cm2 and a total ionizing dose (TID) of 10 kGy. In this article, the radiation tolerance measured in several irradiation campaigns is discussed, and the timing performances during a test beam at CERN-H2 with 120-GeV electrons. Additionally, a description of the latest prototype, Proto-1, is provided together with the results of the latest low-energy beam test at the LNF beam test facility (BTF) with 450 MeV electrons
Performance of scintillating tiles with direct silicon-photomultiplier (SiPM) readout for application to large area detectors
No full textThe light yield, the time resolution and the efficiency of different types of scintillating tiles with direct Silicon Photomultiplier readout and instrumented with a customised front-end electronics have been measured at the Beam Test Facility of Laboratori Nazionali di Frascati and several test stands. The results obtained on minimum ionising particles with different detector configurations are presented. A time resolution of the order of 300 ps, a light yield of more than 230 photo-electrons, and an efficiency better than 99.8% are obtained with ∼ 225 cm2 large area tiles. This technology is suitable for a wide range of applications in high-energy physics, in particular for large area muon and timing detectors
Characterization of a 5 x 5 LYSO Matrix Calorimeter Prototype
No full textIn this paper, we present measurements of the energy and the time resolution of the Lutetium-Yttrium Oxyorthosilicate (LYSO) calorimeter prototype for the Mu2e experiment. The prototype calorimeter matrix consisted of 25, 3 × 3 × 130 mm^3, LYSO crystals readout by 10 × 10 mm^2 Hamamatsu APDs. The prototype has been tested both with the tagged photon beam at MAMI, Mainz, Germany, and with the e-beam of BTF, Frascati. The energy of particles used ranges between 61.3 and 187.1 MeV (80-130 MeV) for photon (electron) beams. While the MAMI data shows a negligible beam energy spread, we observe a 3%-5% contribution related to the beam in BTF sample. After correcting this effect, we obtain a global energy dependence of the energy resolution described by the formula σE/E_(dep) = a/√(E_(dep)/GeV) ⊕ b, with a = (0.59 ± 0.12)% and b = (3.63 ± 0.21)%. The simulation is in good agreement with data if we add an additional contribution due to the intrinsic LYSO fluctuation of 2.6%. We present also the measurements of the time resolution. The measurements have been performed using the e- beam BTF in the energy range from 100 to 400 MeV. A resolution of (161 ± 3) ps at 100 MeV has been achieved. The energy dependence of the resolution has been fitted with following parametrization: σ_t(E) = a/ √E/GeV ⊕ b, where the stochastic term and the constant term are determined to be a = (50 ± 1) ps and b = (40 ± 3) ps, respectively
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