scispace - formally typeset
Search or ask a question
Topic

Scintillation

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


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, it was shown that the characteristic scintillation of PbWO4 is dominantly blue and subdominantly green, and that the phosphorescence with a decay constant of about 15 ms exists only in Type B at about 500 nm.
Abstract: There are two types of crystals with respect to luminescence. In dc measurement, type A gives a primary emission at 410–430 nm (blue) with a second one at around 500 nm. Type B gives only dominant emission at 480–500 nm (green). This apparent difference can be interpreted as follows; the characteristic scintillation of PbWO4 is dominantly blue and subdominantly green. Intense phosphorescence with a decay constant of about 15 ms exists only in Type B at about 500 nm with one to two orders of magnitude larger intensity than scintillation, hiding the blue scintillation in its tail. The cause of the phosphorescence may be Mo.

83 citations

Journal ArticleDOI
TL;DR: This work investigates the achievable CTR with LGSO:Ce (0.025 mol%) when coupled to new silicon photomultipliers, as it has similar light output and equivalent stopping power for 511 keV annihilation photons compared to industry standard LSO: ce and LYSO:ce, and the decay time is improved by more than 30% with proper Ce concentration.
Abstract: Coincidence time resolution (CTR), an important parameter for time-of-flight (TOF) PET performance, is determined mainly by properties of the scintillation crystal and photodetector used. Stable production techniques for LGSO:Ce (Lu1.8Gd0.2SiO5:Ce) with decay times varying from ∼ 30-40 ns have been established over the past decade, and the decay time can be accurately controlled with varying cerium concentration (0.025-0.075 mol%). This material is promising for TOF-PET, as it has similar light output and equivalent stopping power for 511 keV annihilation photons compared to industry standard LSO:Ce and LYSO:Ce, and the decay time is improved by more than 30% with proper Ce concentration. This work investigates the achievable CTR with LGSO:Ce (0.025 mol%) when coupled to new silicon photomultipliers. Crystal element dimension is another important parameter for achieving fast timing. 20 mm length crystal elements achieve higher 511 keV photon detection efficiency, but also introduce higher scintillation photon transit time variance. 3 mm length crystals are not practical for PET, but have reduced scintillation transit time spread. The CTR between pairs of 2.9 × 2.9 × 3 mm(3) and 2.9 × 2.9 × 20 mm(3) LGSO:Ce crystals was measured to be 80 ± 4 and 122 ± 4 ps FWHM, respectively. Measurements of light yield and intrinsic decay time are also presented for a thorough investigation into the timing performance with LGSO:Ce (0.025 mol%).

83 citations

Journal ArticleDOI
TL;DR: In this paper, the Parkes Pulsar Timing Array was used to make more complete models of the ESE, including an estimate of the "outer-scale" of the turbulence in the plasma lens.
Abstract: Extreme scattering events (ESEs) in the interstellar medium (ISM) were first observed in regular flux measurements of compact extragalactic sources. They are characterized by a flux variation over a period of weeks, suggesting the passage of a "diverging plasma lens" across the line of sight (LOS). Modeling the refraction of such a lens indicates that the structure size must be of the order of AU and the electron density of the order of 10s of cm^(−3). Similar structures have been observed in measurements of pulsar intensity scintillation and group delay. Here we report observations of two ESEs, showing increases in both intensity scintillation and dispersion made with the Parkes Pulsar Timing Array. These allow us to make more complete models of the ESE, including an estimate of the "outer-scale" of the turbulence in the plasma lens. These observations clearly show that the ESE structure is fully turbulent on an AU scale. They provide some support for the idea that the structures are extended along the LOS, such as would be the case for a scattering shell. The dispersion measurements also show a variety of AU scale structures that would not be called ESEs, yet involve electron density variations typical of ESEs and likely have the same origin.

83 citations

Journal ArticleDOI
TL;DR: The results reveal that the rise time can significantly change the timing resolution of fast scintillators that have short decay time constants, and the new timing model significantly improves the accuracy in the calculation of timing resolutions.
Abstract: The coincidence timing resolution is a critical parameter which to a large extent determines the system performance of positron emission tomography (PET). This is particularly true for time-of-flight (TOF) PET that requires an excellent coincidence timing resolution (<<1 ns) in order to significantly improve the image quality. The intrinsic timing resolution is conventionally calculated with a single-exponential timing model that includes two parameters of a scintillator detector: scintillation decay time and total photoelectron yield from the photon-electron conversion. However, this calculation has led to significant errors when the coincidence timing resolution reaches 1 ns or less. In this paper, a bi-exponential timing model is derived and evaluated. The new timing model includes an additional parameter of a scintillator detector: scintillation rise time. The effect of rise time on the timing resolution has been investigated analytically, and the results reveal that the rise time can significantly change the timing resolution of fast scintillators that have short decay time constants. Compared with measured data, the calculations have shown that the new timing model significantly improves the accuracy in the calculation of timing resolutions.

83 citations

Journal ArticleDOI
TL;DR: In this article, the response of CsI(Tl) scintillators to heavy ions is investigated as a function of E, A, and Z, in addition to the expected dependence of light output on Z and E, a significant dependence on mass number is observed.
Abstract: The response of CsI(Tl) scintillators to heavy ions is investigated as a function of E , A , and Z . In addition to the expected dependence of light output on Z and E , we observe a significant dependence on mass number. A simple parameterization of the quenching in terms of a few physical variables permits characterization of the light output for a variety of nuclear species with a single quenching constant.

82 citations


Network Information
Related Topics (5)
Electron
111.1K papers, 2.1M citations
80% related
Scattering
152.3K papers, 3M citations
80% related
Magnetic field
167.5K papers, 2.3M citations
78% related
Electric field
87.1K papers, 1.4M citations
78% related
Beam (structure)
155.7K papers, 1.4M citations
77% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023429
2022972
2021405
2020521
2019561
2018566