1,349 research outputs found
Performance of the INFN Camera calibration device of the first Large Size Telescope in the Cherenkov Telescope Array
No full textOn October 10th 2018 started the commissioning of the first Large Size Telescope (LST) prototype at the Cherenkov Telescope Array (CTA) northern site at the Observatorio del Roque de los Muchachos, Canary Island of La Palma (Spain). For a precise event energy reconstruction, an LST camera requires a uniform and constant calibration over a large dynamic range, up to 104 photo-electrons (p.e.), for each camera photomultiplier tube (PMT). This paper describes the performance of the LST-1 camera calibration system (named CaliBox) in the first commissioning period and provides preliminary results of measurements of the light flat field
Electron-muon identification by atmospheric shower and electron beam in a new eas detector concept
No full textWe present results demonstrating the time resolution and μ/e separation capabilities of a new concept
for an EAS detector capable of measuring cosmic rays arriving with large zenith angles. This kind of detector has been
designed to be part of a large area (several square kilometer) surface array designed to measure ultra high energy
(10–200 PeV)τ neutrinos using the Earth-skimming technique. A criterion to identify electron-gammas is also
shown and the particle identification capability is tested by measurements in coincidence with the KASKADE-
GRANDE experiment in Karlsruhe, Germany
The Selective Role of Open and Endoscopic Approaches for Sinonasal Malignant Tumours
No full textLópez F., Shah J.P., Beitler J.J., Snyderman C.H., Lund V., Piazza C., Mäkitie A.A., Guntinas-Lichius O., Rodrigo J.P., Kowalski L.P., Quer M., Shaha A., Homma A., Sanabria A., Ferrarotto R., Lee A.W.M., Lee V.H.F., Rinaldo A., Ferlito A
Performance of the INFN Camera calibration device of the first Large Size Telescope in the Cherenkov Telescope Array
No full textInternational audienceAt the end of 2018, the prototype of the first Large Size atmospheric Cherenkov Telescope (LST-1) proposed for the Cherenkov Telescope Array (CTA) observatory has been completed at the Observatorio del Roque de Los Muchachos in La Palma (Canary Islands, Spain). The LST-1 camera, with more than 1800 photomultipliers (PMTs), requires a precise and regular flat field photo-electron (p.e.) calibration.We present the characteristics and performance of the system (Camera Calibration Box, CaliBox), installed at the center of the LST-1 dish, which provides the optical calibration for the camera PMTs, over a large dynamic range up to p.e. per pixel (1 pixel = 1 PMT).The CaliBox consists of a pulsed UV laser with a wavelength of 355 nm (corresponding to the maximum of the PMT quantum efficiency) and a 400 ps pulse width, a set of filters to guarantee a large dynamic range of photons on each pixel, and a diffusing Ulbricht sphere to integrate and uniformly spread the laser light over the camera plane 28 m away. The CaliBox is designed to be hermetically closed and filled with dry air to make the system completely isolated from the external environment and maintain a controlled low internal relative humidity.An additional inter-calibration system provides the absolute (and relative) number of p.e. for each filter combination in addition to a self-diagnose mechanism.The system is completely managed by an internal ODROID-C1+ board , which can be remotely controlled via an Open Platform Communication's Unified Architecture (OPC-UA) protocol
Searching for the X17 with the PADME experiment
No full textCertain classes of dark matter theories predict the existence of a new, hidden “Dark Sector” of particles which interact with Standard Model particles only through the exchange of a new, massive mediator. This is the scenario that the Positron Annihilation into Dark Matter Experiment (PADME) was originally designed to test using the positron beam at the Beam Test Facility (BTF) at the INFN Laboratori Nazionali di Frascati (LNF). The confirmation of the X17 anomaly in 2021, observed in internal pair creation nuclear decays at the ATOMKI institute in Debrecen, Hungary, kindled significant interest within the particle physics community. Assuming that the anomaly comes from the decay of a new particle to an e+e− pair, time-reversal symmetry implies that the new particle must be producible in e+e− annihilation. Since the beam used at PADME is the only one worldwide with the correct energy to create this new particle on resonance, the PADME collaboration pivoted to study the X17 anomaly in the reaction e+e− → X17 → e+e−,
aiming to confirm/disprove the particle hypothesis. In 2022, PADME Run III was dedicated specifically to this search. Approximately 1010 positrons on target were collected for each of the 47 beam energy values in the range 262 ÷ 298 MeV. This paper gives an overview of the scientific program of the experiment and of the data analyses ongoing
Performance of the Prototype of the Charged-Particle Veto System of the PADME Experiment
No full textThe PADME experiment will search for the e+ e- →γ A′ process in a positron-on-target experiment, assuming a decay of the A′ into invisible particles of the hidden sector. The 550-MeV positron beam of the DApdblNE beam-test facility (BTF), at Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, will be used. The suppression of the background, due to bremsstrahlung emission from the beam positrons, requires highly efficient charged-particle detectors with optimized geometry. A fine-grained plastic scintillator veto composed of three stations operating in vacuum is proposed. Two stations, placed inside a dipole magnet with 0.6-T magnetic field, will also provide momentum measurement at the percent level. Different prototypes for the design of the detector elements, the photosensor, and the front-end electronics were studied with single electron beam at the DApdblNE BTF to choose the optimal technologies and construction solutions. PADME is currently under construction, and it is planned to begin data collection in 2018. The design of the charged-particle vetoes and the test beam performance of the prototypes are reviewed
Structural Health Monitoring of Composite Aircraft Structures Using Fiber Bragg Grating Sensors
No full textAircraft industry is continually striving towards reducing the acquisition, operation and maintenance costs. Usage of advanced composite materials in primary aircraft structures have resulted in significant weight savings owing to their higher specific strength and specific stiffness. Composite structures, in spite of their inherent advantages, are prone to various damages. To detect and repair various structural damages that can occur during the service life of the aircraft, a thorough inspection schedule is implemented through conventional visual and Non Destructive Evaluation methods. Such scheduled inspections lead to considerable increase in maintenance cost & down-time of the aircraft. An online structural health monitoring (SHM) system consisting of well-designed sensor networks incorporated in the structure along with necessary hardware and software can provide information about the structure, thereby leading to reporting of flaws or damages in real time. Such a system can provide inputs for condition based maintenance which can result in reduced maintenance cost. This paper presents the work carried out at CSIR-National Aerospace Laboratories towards developing a flight-worthy SHM system and its demonstration on an unmanned aerial vehicle (UAV). Sensor selection, characterization, instrumentation design, algorithm development towards damage detection & load estimation at lab level and implementation of the technology on a UAV are discussed in this paper
Performance of the PADME Calorimeter prototype at the DAΦNE BTF
No full textThe PADME experiment at the DAΦNE Beam-Test Facility (BTF) aims at searching for invisible decays of the dark photon by measuring the final state missing mass in the process e+e−→γ+A′, with A′ undetected. The measurement requires the determination of the 4-momentum of the recoil photon, performed using a homogeneous, highly segmented BGO crystals calorimeter. We report the results of the test of a 5×5 crystals prototype performed with an electron beam at the BTF in July 2016
- …
