Search results for "Gamma"
showing 10 items of 3093 documents
Early warning for VHE gamma-ray flares with the ARGO-YBJ detector
2011
Detecting and monitoring emissions from flaring gamma-ray sources in the very-high-energy (VHE, > 100 GeV) band is a very important topic in gamma-ray astronomy. The ARGO-YBJ detector is characterized by a high duty cycle and a wide field of view. Therefore, it is particularly capable of detecting flares from extragalactic objects. Based on fast reconstruction and analysis, real-time monitoring of 33 selected VHE extragalactic sources is implemented. Flares exceeding a specific threshold are reported timely, hence enabling the follow-up observation of these objects using more sensitive detectors, such as Cherenkov telescopes. (C) 2011 Elsevier B.V. All rights reserved.
"Table 12" of "Search for heavy resonances decaying to a photon and a hadronically decaying $Z/W/H$ boson in $pp$ collisions at $\sqrt{s}=13$ $\mathr…
2018
Distribution of the reconstructed J+gamma invariant mass in W+gamma search ELSE category.
"Table 10" of "Search for heavy resonances decaying to a photon and a hadronically decaying $Z/W/H$ boson in $pp$ collisions at $\sqrt{s}=13$ $\mathr…
2018
Distribution of the reconstructed J+gamma invariant mass in W+gamma search D2 category.
"Table 11" of "Search for heavy resonances decaying to a photon and a hadronically decaying $Z/W/H$ boson in $pp$ collisions at $\sqrt{s}=13$ $\mathr…
2018
Distribution of the reconstructed J+gamma invariant mass in W+gamma search VMASS category.
B-MINE, the balloon-borne microcalorimeter nuclear line explorer
2001
B-MINE is a concept for a balloon mission designed to probe the deepest regions of a supernova explosion by detecting Ti-44 emission at 68 keV with spatial and spectral resolutions that are sufficient to determine the extent and velocity distribution of the Ti-44 emitting region. The payload introduces the concept of focusing optics and microcalorimeter spectroscopy to nuclear line emission astrophysics. B-MINE has a thin, plastic foil telescope multilayered to maximize the reflectivity in a 20 keV band centered at 68 keV and a microcalorimeter array optimized for the same energy band. This combination provides a reduced background, an energy resolution of 50 eV and a 3sigma sensitivity in …
Charge Sharing and Cross Talk Effects in High-Z and Wide-Bandgap Compound Semiconductor Pixel Detectors
2023
Intense research activities have been made in the development of high-Z and wide-bandgap compound semiconductor pixel detectors for the next generation X-ray and gamma ray spectroscopic imagers. Cadmium telluride (CdTe) and cadmium-zinc-telluride (CdZnTe or CZT) pixel detectors have shown impressive performance in X-ray and gamma ray detection from energies of few keV up to 1 MeV. Charge sharing and cross-talk phenomena represent the typical drawbacks in sub-millimeter pixel detectors, with severe distortions in both energy and spatial resolution. In this chapter, we review the effects of these phenomena on the response of CZT/CdTe pixel detectors, with particular emphasis on the current st…
Digital Pulse-Processing Techniques for X-Ray and Gamma-Ray Semiconductor Detectors
2017
Over the last decade, digital pulse-processing (DPP) electronics have been widely proposed and used for new generation x- and gamma-ray spectrometers. DPP systems, based on direct digitizing and processing of detector signals, lead to better results than the traditional analog pulse-processing electronics in terms of stability, flexibility, reproducibility, energy resolution, throughput, and dead time. In this chapter, we will review the principles of operation of conventional analog electronic chains for x- and gamma-ray semiconductor detectors, with special emphasis on the benefits of the digital approach. The characteristics of a new real-time DPP system, developed by our group, are disc…
Ballistic Deficit Pulse Processing in Cadmium-Zinc-Telluride Pixel Detectors for High-Flux X-ray Measurements.
2022
High-flux X-ray measurements with high-energy resolution and high throughput require the mitigation of pile-up and dead time effects. The reduction of the time width of the shaped pulses is a key approach, taking into account the distortions from the ballistic deficit, non-linearity, and time instabilities. In this work, we will present the performance of cadmium–zinc–telluride (CdZnTe or CZT) pixel detectors equipped with digital shapers faster than the preamplifier peaking times (ballistic deficit pulse processing). The effects on energy resolution, throughput, energy-linearity, time stability, charge sharing, and pile-up are shown. The results highlight the absence of time instabilities …
Time-dependent current-voltage characteristics of Al/p-CdTe/Pt x-ray detectors
2012
Current-voltage (I-V) characteristics of Schottky Al/p-CdTe/Pt detectors were investigated in dark and at different temperatures. CdTe detectors with Al rectifying contacts, very appealing for high resolution x-ray and gamma ray spectroscopy, suffer from bias-induced polarization phenomena which cause current increasing with the time and severe worsening of the spectroscopic performance. In this work, we studied the time-dependence of the I-V characteristics of the detectors, both in reverse and forward bias, taking into account the polarization effects. The I-V measurements, performed at different time intervals between the application of the bias voltage and the measurement of the current…
The LOFT mission concept: a status update
2016
The Large Observatory For x-ray Timing (LOFT) is a mission concept which was proposed to ESA as M3 and M4 candidate in the framework of the Cosmic Vision 2015-2025 program. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument and the uniquely large field of view of its wide field monitor, LOFT will be able to study the behaviour of matter in extreme conditions such as the strong gravitational field in the innermost regions close to black holes and neutron stars and the supra-nuclear densities in the interiors of neutron stars. The science payload is based on a Large Area Detector (LAD, >8m2 effective area, 2-30 keV, 240 eV spectral resolut…