Scintillation

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

Prospects for time-of-flight PET using LSO scintillator

Abstract: We present measurements of the timing properties of lutetium orthosilicate (LSO) scintillator crystals coupled to a photomultiplier tube (PMT) and excited by 511 keV photons. These crystals have dimensions suitable for use in PET cameras (3/spl times/3/spl times/30 mm/sup 3/). Coincidence timing resolution of 475 ps fwhm is measured between detectors utilizing two such crystals, significantly worse than the 300 ps fwhm predicted based on first principles for small crystals and measured in 3 mm cubes. This degradation is found to be caused by the scintillation light undergoing multiple reflections at quasi-random angles within the scintillator crystal, which has two effects. First, it slows down the effective information propagation speed within the crystal (to an effective n/spl circ/=3.9-5.3). Since the incident annihilation photon travels with n=1, information from interactions at different depths arrives at the PMT with different time delays. Second, the random nature of the reflection angles (and path lengths) introduce dispersion and so a 10%-90% rise time of 1 ns to the optical signal.

Inorganic scintillating materials and scintillation detectors.

Abstract: Scintillation materials and detectors that are used in many applications, such as medical imaging, security, oil-logging, high energy physics and non-destructive inspection, are reviewed. The fundamental physics understood today is explained, and common scintillators and scintillation detectors are introduced. The properties explained here are light yield, energy non-proportionality, emission wavelength, energy resolution, decay time, effective atomic number and timing resolution. For further understanding, the emission mechanisms of scintillator materials are also introduced. Furthermore, unresolved problems in scintillation phenomenon are considered, and my recent interpretations are discussed. These topics include positive hysteresis, the co-doping of non-luminescent ions, the introduction of an aimed impurity phase, the excitation density effect and the complementary relationship between scintillators and storage phosphors.

The Physics of Pulsar Scintillation

Abstract: Scintillation is a well-known phenomenon in astronomy, e.g. twinkling of stars due to scattering in the Earth’s atmosphere, and variability of compact radio sources due to scattering in the ionosphere and the solar wind. These examples correspond to the so-called regime of weak scattering. Radio pulsars scintillate as a result of scattering in the ionized interstellar medium, but in contrast to the previous cases, the physical regime corresponds to strong scattering. Pulsars exhibit two distinct kinds of variability, called diffractive scintillation and refractive scintillation, on timescales of minutes and weeks respectively. The physics of the various regimes of scintillation are reviewed, and some basic theoretical results are summarized. The properties of imaging in the presence of strong scattering are also discussed.