Graduation date: 1995

The general characteristics of infrared sensitive phosphors are discussed, with particular emphasis on SrS. CeSm, known as Standard VII, which is the subject of this research. The apparatus is described, and consists of an infrared spectrometer, a photomultiplier and a direct coupled amplifier. The performance is discussed in some detail. Curves of the decay of phosphorescence for Standard VII are described; it is found that on a log-time log-brightness plot, these curves are straight lines for times greater than ten minutes. The limiting slope depends on the time of excitation, and is related to it by a simple law. It is also established that there are two types of colour centers active during phosphorescent decay, cerium and samarium. The emission of cerium is a band with peak at .485 microns, and that of samarium a series of lines in the red. A number of simplified theories are developed or described, no one of which exactly fit the data. It is suggested that the curves can probably be fitted by an exponential distribution of shallow traps if absorption and scattering are considered. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Graduation date: 1997

Graduation date: 1997

No description available.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [131]-140).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 65-67). Also available via the Internet.

In this thesis I have given an account of the work carried out by me on the measurement of the spectra and decay times of a few selected organic phosphors under ultraviolet and ionising radiation. The purpose of the investigation has been to attempt to throw more light on the mechanism by which energy migrates within the crystalline lattice. A general introduction is given to the process of fluorescence and the various proposed theories by which the excitation energy, which eventually appears as fluorescence light, is able to move about in the crystalline lattice. Preface, p. 1.

No description available.

No description available.