. Carnegie Institution of Washington publication. DECAY OF PHOSPHORESCENCE PRODUCED BY HEATING. 93 The effect of delay between the end of excitation and the beginning of heating was investigated at some length. The general character of the results obtained is given in Fig. 90 and the subsequent diagrams. Fig. 90 shows the way in which the outburst of thermo-luminescence diminishes in intensity, in the case of a substance excited for a given time and subsequently heated in a furnace of given temperature, as the interval of time before the beginning of heating is Figs. 92 and 93. in
. Carnegie Institution of Washington publication. DECAY OF PHOSPHORESCENCE PRODUCED BY HEATING. 93 The effect of delay between the end of excitation and the beginning of heating was investigated at some length. The general character of the results obtained is given in Fig. 90 and the subsequent diagrams. Fig. 90 shows the way in which the outburst of thermo-luminescence diminishes in intensity, in the case of a substance excited for a given time and subsequently heated in a furnace of given temperature, as the interval of time before the beginning of heating is Figs. 92 and 93. in which time is measured from the beginning of heating, indicate clearly a shift in the time of reaching the maximum of intensity of thermo- luminescence in the same direction as that already noted in the case of increased length of excitation. The energy of phosphorescence does not manifest itself so rapidly after long delay in heating or long excita- tion as after short delay or short ex- citation. For any given excitation and temperature the curves tend to coincide after a given time, which may be taken to indicate that the interval of time occupied by an out- \ burst of thermo-luminescence is in- dependent of the time which has elapsed since excitation. Table 16 gives the approximate duration of the flash of thermo- luminescence from nine sets of observations under varying condi- tions of excitation and heating. Fig. While the times stated are neces- sarily somewhat inaccurate, they indicate that brief outbursts follow short exposures and high temperatures of the furnace and vice versa. â X -*â f 400 800 1200 Fig. 92. Effect of delay in heating. Time measured from beginning of heating. Excited 320seconds at room temperature. Tem- perature of furnace 03° C The time between the end of excitation and the beginning of heating is as follows: Curve 1, sec; curve 2, sec; curve 3, sec; curve 4,; curves, ; curve 6, sec. JThe location
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