Showing papers by "Charles L. Melcher published in 1992"
01 Apr 1992-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, a new inorganic single crystal scintillator, Lu2(SiO4)O:Ce (or "LSO") was discovered, which has a unique combination of properties including high emission intensity, fast decay time, high density, and high atomic number.
Abstract: We have discovered a new inorganic single crystal scintillator [1], lutetium oxyorthosilicate doped with cerium, Lu2(SiO4)O:Ce (or “LSO”), which has a unique combination of properties including high emission intensity, fast decay time, high density, and high atomic number. These properties result in excellent signal-to-noise, fast coincidence timing, high count-rate capability, and high detection efficiency making LSO superior to any other known scintillator for many applications. This new scintillator has several important advantages over the scintillator crystals currently used for the detection of gamma rays or X-rays in applications such as medical imaging, nuclear and particle physics, and geophysical exploration. Here we compare the properties of LSO to those of the two most widely used scintillators, namely thallium-doped sodium iodide and bismuth germanate.
268 citations
15 Aug 1992-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, the gamma-ray and UV-excitation of cerium-doped rare-earth oxyorthosilicates (RE = Y, Gd, and Lu) has been used to investigate the emission mechanism for this family of scintillators.
Abstract: Gamma-ray and UV-excitation of cerium-doped rare-earth oxyorthosilicates (RE = Y, Gd, and Lu) has been used to investigate the emission mechanism for this family of scintillators. The data clearly indicate the presence of two different luminescence centers, which are attributed to cerium substitution in the two different rare-earth crystallographic sites. While this model explains much of the present and previous UV data, the gamma-ray induced emission from GSO requires a better understanding of the energy transfer between Gd and Ce.
239 citations
25 Oct 1992
TL;DR: In this article, the existence of two activation centers for Lu/sub 2/(SiO/sub 4/)O:Ce (LSO) was proposed and two different decay time constants of the order of tens of nanoseconds, which are characteristic for fast Ce emission, were shown at 77 K and 11 K, respectively.
Abstract: Two types of excitation and emission spectra with ultraviolet excitation are shown at 11 K for Lu/sub 2/(SiO/sub 4/)O:Ce (LSO) Since there are two crystallographically independent lutetium sites in LSO, the existence of two Ce activation centers (two-activation-center model) is proposed The existence of two different decay time constants of the order of tens of nanoseconds, which are characteristic for fast Ce emission, are shown at 77 K Although the temperature dependence of the decay time and the luminescence efficiency could not be measured for the Ce2, the fact that the gamma-ray-excited emission can be reconstructed from a weighted combination of the Ce1 and Ce2 emission spectra supports the two-activation-center model for LSO >
140 citations