THEORETICAL-STUDY OF A VACUUM ULTRAVIOLET F2 EXCIMER LAMP (157 NM) EXCITED BY MICROWAVE-DISCHARGE

A high-efficiency operation of a vacuum ultraviolet (VUV) incoherent light source of a F2 excimer lamp [157 nm:F2(D')-F2(A')] excited by a pulsed microwave discharge has theoretically been studied. Despite the low-pressure (300 Torr) operation, an intrinsic efficiency of 10.6% and a F2(D') formation efficiency of 17.4% were found to be obtainable at an optimum F2 concentration (0.5%) using He/F2 Mixtures. The F2(D') state is mainly produced by energy transfer reaction from F*. Using a 300 Torr mixture of He/F2 = 99.5/0.5(%), a photon extraction efficiency of 60.9% is achievable with a low energy loss (39.1%) by collisional quenching. The corresponding optical output of 50.0-mu-J/cm3 is achievable at an excitation rate of 100 W/cm3 and an excitation pulse width of 9.0-mu-s. Since it can be operated at high repetition frequency of up to 55 kHz using conventional devices, an average output power of 2.75 W/cm3 is achievable.