THE DECAY OF DELAYED LIGHT AT SHORT TIMES 

 William Arnold and J. B. Davidson 



In this brief report we would like to present some preliminary results 

 of measurements of the decay of the delayed light emission from Chlorella in 

 the time region of 10~~* to 10"*^ seconds. Although the experiments are still 

 in progress, we feel that the data are of sufficient interest to warrant presenting 

 them to this Symposium. 



The results were mainly obtained with two devices which will be described 

 in detail in a future paper. One is a phosphoroscope patterned after one used 

 by Dr. R. S. Becker at the University of Houston. It covers the range of from 

 0.65 to 1 000 milliseconds. The second device is a shutter consisting of a small 

 piece of 0.25 mil aluminized Mylar film operated by the blast from a carbon 

 dioxide pistol. This shutter was used in the 50 to 1000 microseconds range. 



Figure 1 is a composite decay curve for Chlorella at 25° C. 



10^ 



10^1 



.^10^ 



< 

 c/)10- 



10- 



•• \ 



10'" 10"' 



10 1 10 



TIME (sec) 



10^ 10' lO" 



698 



