VACUUM-ULTRAVIOLET CERENKOV RADIATION SOURCE.

A report is presented on measurements performed to characterize vacuum-ultraviolet Cerenkov radiation generated with a gas cell and optical system, installed in a primary beam line of the Stanford Linear Accelerator Center 20-Gev electron linac. Variation of the helium pressure in the cell resulted in collected radiation which was tunable from 800 A through the visible, had a bandwidth of approximately equals 4% at 1000 A, a photon flux of approximately equals 10**1**2 photons/sec mA of beam current, and a time structure identical to that of the electron beam. Measured radiation properties are compared to calculated predictions to indicate where improvements in the system design and fabrication could be made.