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Scintillation

About: Scintillation is a research topic. Over the lifetime, 14022 publications have been published within this topic receiving 187694 citations.


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TL;DR: In this article, a new scintillators for high-resolution gamma ray spectroscopy have been identified, grown and characterized, focusing on two classes of high-light-yield materials: europium-doped alkaline earth halides and ceriumdoped garnets.
Abstract: New scintillators for high-resolution gamma ray spectroscopy have been identified, grown and characterized. Our development efforts have focused on two classes of high-light-yield materials: europium-doped alkaline earth halides and cerium-doped garnets. Of the halide single crystals we have grown by the Bridgman method-SrI2, CaI2, SrBr2, BaI2 and BaBr2-SrI2 is the most promising. SrI2(Eu) emits into the Eu2+ band, centered at 435 nm, with a decay time of 1.2 mus and a light yield of up to 115,000 photons/MeV. It offers energy resolution better than 3% FWHM at 662 keV, and exhibits excellent light yield proportionality. Transparent ceramic fabrication allows the production of gadolinium- and terbium-based garnets which are not growable by melt techniques due to phase instabilities. The scintillation light yields of cerium-doped ceramic garnets are high, 20,000-100,000 photons/MeV. We are developing an understanding of the mechanisms underlying energy dependent scintillation light yield non-proportionality and how it affects energy resolution. We have also identified aspects of optical design that can be optimized to enhance the energy resolution.

232 citations

Journal ArticleDOI
TL;DR: In this article, the authors compare X-ray scintillator characteristics of three-dimensional (3D) MAPbI3 and MAPbBr3 and two-dimensional(2D) (EDBE)PbCl4 hybrid perovskite crystals.
Abstract: Current technologies for X-ray detection rely on scintillation from expensive inorganic crystals grown at high-temperature, which so far has hindered the development of large-area scintillator arrays. Thanks to the presence of heavy atoms, solution-grown hybrid lead halide perovskite single crystals exhibit short X-ray absorption length and excellent detection efficiency. Here we compare X-ray scintillator characteristics of three-dimensional (3D) MAPbI3 and MAPbBr3 and two-dimensional (2D) (EDBE)PbCl4 hybrid perovskite crystals. X-ray excited thermoluminescence measurements indicate the absence of deep traps and a very small density of shallow trap states, which lessens after-glow effects. All perovskite single crystals exhibit high X-ray excited luminescence yields of >120,000 photons/MeV at low temperature. Although thermal quenching is significant at room temperature, the large exciton binding energy of 2D (EDBE)PbCl4 significantly reduces thermal effects compared to 3D perovskites, and moderate light yield of 9,000 photons/MeV can be achieved even at room temperature. This highlights the potential of 2D metal halide perovskites for large-area and low-cost scintillator devices for medical, security and scientific applications.

231 citations

Journal Article
TL;DR: In this paper, dual-frequency observations of flat and steep-spectrum extragalactic radio sources made at Arecibo Observatory over a 20-day period are analyzed.
Abstract: Dual-frequency observations of flat and steep-spectrum extragalactic radio sources made at Arecibo Observatory over a 20-day period are analyzed. As first reported by Heeschen (1982, 1984), flat-spectrum sources generally have larger intensity variations than steep-spectrum ones. A structure function analysis demonstrates a qualitative difference in the time series of the sources. The case against interstellar scintillation is examined, including a review of applicable scintillation theory. Relativistic source motion is treated as a solution to the brightness-temperature problems which arise if the variations are assumed intrinsic to the sources. 16 references.

231 citations

Journal ArticleDOI
TL;DR: In this article, the relationship between the statistics of log-amplitude fluctuations and irradiance fluctuations due to atmospheric turbulence is derived and the effect of use of a large aperture diameter in reducing the variance of a fluctuating signal is evaluated.
Abstract: The relationship between the statistics of log-amplitude fluctuations and irradiance fluctuations due to atmospheric turbulence is derived This is used to evaluate the effect of use of a large aperture diameter in reducing the variance of a fluctuating signal Curves for the reduction factor are presented From these, an irradiance-fluctuation correlation distance is evaluated This distance, unlike the correlation distance for log-amplitude fluctuations, is found to be a function of the log-amplitude variance A particular example of the application of these results to a space-to-ground communications systems performance is worked out

230 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used amplitude scintillation measurements of L1 (1.575MHz) signals from GPS satellites at Ascension Island (14.45° W, 7.95° S; magnetic latitude 16° S) during February-April, 1998, to compare amplitude scints with fluctuations of the total electron content (TEC).

228 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023429
2022972
2021405
2020521
2019561
2018566