Muon-induced visual sensations.

The visual phenomena induced by the passage of a pulse of extremely relativistic muons through the vitreous humor have been studied at the Alternating Gradient Synchrotron at Brookhaven National Laboratory. The visual phenomena include flashes that range from small crescents of light in the peripheral field of view to large clouds of light that fill the entire field of view as well as bright flashes with dark centers. Three subjects have been exposed to date. Arguments are given to show that the physical mechanism behind these flashes is Cerenkov radiation. Standard psychophysical techniques are used to determine the threshold for muoninduced visual sensations for one subject. Comparison is made with his pion treshold measured under the same condition.