Vacuum-ultraviolet emission from high-pressure krypton

Krypton gas was excited by high-current relativistic electron bursts, and spectral and temporal characteristics of the uv continuum peaked at 1460 Å were measured as functions of pressure. Gas pressure ranged from 0.14 to 68 atm. The spectral full width at half-maximum of 90±6 Å was virtually independent of pressure from 3.4 to 68 atm. Exponential time constants for the buildup and decay of the uv intensity obeyed a $P^{-1.5\mathrm{}}$ pressure dependence for $P<\mathrm{}4\mathrm{}$ atm. Three pressure-independent intensity decay constants of 9±1.5, 32±6, and 350±70 nsec were obtained for $P>\mathrm{}6\mathrm{}$ atm. The efficiency for conversion of electron kinetic energy to uv energy was (4±1.6)%.