Optical characteristics of UV-VUV lamps on the electronic-vibrational transitions of the hydroxyl radical pumped by a nanosecond capacitive discharge

This paper presents the results of a study of UV and VUV low-pressure lamp pumped by nanosecond capacitive discharge.This lamp works on the mixtures of helium and argon with water vapor(H_(2)O)or‘heavy’water(D_(2)O).At the capacitive low-pressure lamp emission spectra are mainly narrow band 308 nm OH(A-X)and large band in the VUV spectral range:140-200 nm OH(C,B,A).Found,that the increasing the partial pressure of H_(2)O and D_(2)O(>130-150 Pa)led to a decrease in the intensity of VUV radiation of hydroxyl radicals.In the transition from He/H_(2)O mixture to He/D_(2)O mixture,the optimal pressure of helium is decreased.Reduced partial pressure of argon led to increased intensity of radiation of hydroxyl in the VUV range.The study of emission characteristics of OD^(*)-lamps on a mixture of He/D_(2)O and the OH^(*)-lamps on a mixture of He/H_(2)O showed that the intensity of the bands OD(X,C,A)is 1.5 times larger than the intensity of the bands OH(X,C,A).The maximum absolute intensity of UV-VUV radiation of the lamp(at a frequency of 1000 Hz)reached 1 W.