Growth and decay of phosphorescence in calcium sulphide by a photoelectric method

✍ Scribed by Peter J. Mulder

• Book ID: 104131526
• Publisher: Elsevier Science
• Year: 1938
• Tongue: English
• Weight: 598 KB
• Volume: 225
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/s0016-0032(38)90615-5

✦ Synopsis

The phosphorescence of the calcium sulphide was excited by light and the intensity of the combined radiation of all stimulated wave-lengths was measured as a function of time by means of photoelectric cell, the current from which was amplified by a special vacuum tube amplifier . The amplified currents deflected a galvanometer, the deflection of which was found to be strictly proportional to the intensity of the light falling on the cell, Decay curves for different durations of excitation of the simple were obtained, the decay in intensity during the first thirty seconds after excitation being automatically recorded . Similar curves were obtained for identical durations of excitation at various temperatures of the sample . The effects of several different binders for the calcium sulphide powder were also investigated . A single empirical equation for sulphide in a given binder was obtained, by means of which the intensity of the phosphorescence can be computed for any time after excitation begins, and for any temperature within the range studied .