Scintillation

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

C and L band transionospheric scintillation experiment: Some results for applications to satellite radio systems

Abstract: Satellite radio systems suffer loss of information in a wide band of frequencies during periods of intense ionospheric scintillation activity when the received signal undergoes rapid and deep fading. In order to assess the problem and to determine a proper fade margin for an Earth-space link, system engineers require information on signal statistics as well as on the morphological aspects of scintillations. Our observations near the northern boundary of the equatorial scintillation belt at (18.9° N geomagnetic) within the Indian zone show that the signal at 4/1.5 Ghz has faded often beyond 10 dB pp, and at times beyond 24 dB pp at 4 Ghz during equinoctial months of high solar activity during the years of 1989–1990. In addition to the morphology at 4 Ghz, information on signal statistics, such as cumulative amplitude distribution function, fade rate distribution, and signal reliability for different message lengths for some events of scintillations, both at C and L band, has been presented. The theoretical Nakagami m distribution has been found to be the best for describing various levels of fade. Autocorrelation and power-spectrum analysis have been used to estimate average fade rates and ground correlation distances. Performance evaluation of satellite Earth terminals using small antennas has been carried out to show the vulnerability of the system in the hostile ionospheric environment notwithstanding the advanced modulation systems being employed.

Response of CsI(Tl) scintillators over a large range in energy and atomic number of ions. Part I: recombination and δ-electrons

Abstract: A simple formalism describing the light response of CsI(Tl) to heavy ions, which quantifies the luminescence and the quenching in terms of the competition between radiative transitions following the carrier trapping at the Tl activator sites and the electron–hole recombination, is proposed. The effect of the δ-rays on the scintillation efficiency is for the first time quantitatively included in a fully consistent way. The light output expression depends on four parameters determined by a procedure of global fit to experimental data.

Strontium iodide scintillators for high energy resolution gamma ray spectroscopy

Abstract: Recently SrI2, a scintillator patented by Hofstadter in 1968, has been rediscovered and shown to possess remarkable scintillation properties. The light output of SrI2:Eu2+ has been measured to be even higher than previously observed and exceeds 120,000 photons/MeV, making it one of the brightest scintillators in existence. The crystal also has excellent energy resolution of less than 3% at 662 keV. The response is highly linear over a wide range of gamma ray energies. The emission of SrI2:Eu2+ and SrI2:Ce3+/Na+ is well-matched to both photomultiplier tubes and blue-enhanced silicon photodiodes. While SrI2:Eu2+ is relatively slow, SrI2:Ce3+/Na+ has a fast response. SrI2 crystals with many different dopant concentrations have been grown and characterized. In this presentation, crystal growth techniques as well as the effects of dopant concentration on the scintillation properties of SrI2, over the range 0.5% to 8% Eu2+ and 0.5% to 2% Ce3+/Na+, will be discussed in detail.