Effect of Pressure on Phosphor Decay

An apparatus has been developed to measure the effect of pressure to over 50 000 atmospheres on the decay rate of phosphors. Three manganese activated phosphors with exponential decay curves were studied. In two cases the rate of decay decreased, in the third case it increased. A tentative explanation is offered. An hexagonal ZnS:Cu phosphor showed little pressure effect to 40 000 atmospheres at which pressure it transformed irreversibly to the cubic form with a sharp increase in decay rate and a large decrease in intensity.