Search results for "detector"
showing 10 items of 3491 documents
Observation of Electron Neutrino Appearance in a Muon Neutrino Beam
2014
The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3$\sigma$ when compared to 4.92 $\pm$ 0.55 expected background events. In the PMNS mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles $\theta_{12}$, $\theta_{23}$, $\theta_{13}$, a mass difference $\Delta m^2_{32}$ and a CP violating phase $\delta_{\mathrm{CP}}$. In this neutrino oscillation scenario, assuming $…
Infrared detection in multifunctional graphene-based transistors
2016
In the last years great attention has been paid to graphene-based devices for optoelectronic applications such as photodetection. In this work, we report on Graphene Field Effect Transistors (GFETs) photoelectrical response due to the photo-transistor effect. Photoelectrical measurements were performed using a 1.55 μm erbium fiber laser. Optical measurements as a function of both the incident laser power and the DC bias of the fabricated devices have been carried out and show that photocurrent increases with the power of the IR beam illuminating the sample.
Photocurrent generation in Graphene Field Effect Transistors (GFETs)
2016
In this work, we focused on the study of Graphene Field Effect Transistors (GFETs) photoelectrical response due to the combination of photovoltaic and photo-thermoelectric effects. The technological steps for the transistors fabrication together with their electro-optic response will be presented. Measurements were performed by using a 405 nm laser diode with AM modulation at 1.33 KHz shined onto the sample under test. GFETs electrical output signals were measured by using a lock-in amplifier synchronized to the same reference frequency of the laser driver. This gave us the possibility to evaluate the optical characteristics as a function of both the incident laser power and the static pola…
Photoelectrical response of Graphene Field Effect Transistors (GFETs)
2016
In this work, we present Graphene Field Effect Transistors (GFETs) with photoelectrical response due to the photovoltaiceffect. Our final aim is to use a GFET to down convert an optical to a radiofrequency signal. The technological steps used for the devices fabrication as well as the photoelectrical characterization will be reported. Photoelectrical measurements were performed by using a 405 nm laser diode source, whose output beam was pulse amplitude-modulated at 1.33 kHz by means of a laser driver. The electrical signal out of the GFETs (in a common source amplifier configuration) was measured using a lock-in amplifier synchronized to the same reference frequency of the laser driver. Thi…
Novel diamond X-ray detectors with patterned reduced graphene oxide contacts
2015
A novel kind of detector based on polycrystalline grade diamond substrate and Reduced Graphene Oxide (RGO) contacts is presented. This detector combines some of the good qualities of diamond (i.e. radiation hardness and almost unique combination of electric, thermal and optical properties) with low- Z contacts. This characteristic together with the possibility of patterning the electrodes with standard lithographic techniques, make this detector particularly suitable for X-ray beam monitors where the intensity and the position of the photon beam needs to be measured with minimal effect on the beam itself (i.e. in-line and highly transmissive measurement). The steps needed to realize our nov…
A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo
2021
This paper presents the gravitational-wave measurement of the Hubble constant (H 0) using the detections from the first and second observing runs of the Advanced LIGO and Virgo detector network. The presence of the transient electromagnetic counterpart of the binary neutron star GW170817 led to the first standard-siren measurement of H 0. Here we additionally use binary black hole detections in conjunction with galaxy catalogs and report a joint measurement. Our updated measurement is H 0 = km s-1 Mpc-1 (68.3% of the highest density posterior interval with a flat-in-log prior) which is an improvement by a factor of 1.04 (about 4%) over the GW170817-only value of km s-1 Mpc-1. A significant …
First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data
2017
Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signal-to-noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, {\it narrow-band} analyses methods have been developed, allowing a fully coherent search for gravitational waves from known …
New Error Measures to Evaluate Features on Three-Dimensional Scenes
2011
In this paper new error measures to evaluate image features in three-dimensional scenes are proposed and reviewed. The proposed error measures are designed to take into account feature shapes, and ground truth data can be easily estimated. As other approaches, they are not error-free and a quantitative evaluation is given according to the number of wrong matches and mismatches in order to assess their validity
H$^{-}$ extraction systems for CERN’s Linac4 H$^{-}$ ion source
2018
Linac4 is a 160 MeV linear H accelerator at CERN. It is an essential part of the beam luminosity upgrade of the Large Hadron Collider (LHC) and will be the primary injector into the chain of circular accelerators. It aims at increasing the beam brightness by a factor of 2, when compared to the currently used 50 MeV linear proton accelerator, Linac2. Linac4’s ion source is a cesiated RF-plasma H ion source. Several beam extraction systems were designed for H beams of 45 keV energy, 50 mA intensity and an electron to H ratio smaller than 5. The goal was to extract a beam with an rms-emittance of mm mrad. One of the main challenges in designing an H extraction system is dumping of the co-extra…
Evidence for Astrophysical Muon Neutrinos from the Northern Sky with IceCube
2015
Results from the IceCube Neutrino Observatory have recently provided compelling evidence for the existence of a high energy astrophysical neutrino flux utilizing a dominantly Southern Hemisphere dataset consisting primarily of nu_e and nu_tau charged current and neutral current (cascade) neutrino interactions. In the analysis presented here, a data sample of approximately 35,000 muon neutrinos from the Northern sky was extracted from data taken during 659.5 days of livetime recorded between May 2010 and May 2012. While this sample is composed primarily of neutrinos produced by cosmic ray interactions in the Earth's atmosphere, the highest energy events are inconsistent with a hypothesis of …