A time-resolved spectrograph for use with triggered light sources

Details are given of a time-resolved spectrograph with writing speeds up to 5 mm/μs (at f/12) which can be used to view weak light sources. The main limitation is that the light source must be able to be triggered reproducibly. This is necessary as the increased effective light intensity needed to obtain a usable image density in the camera of the spectrograph is produced by the accurate superposition of the light of many discharges. An experiment is described which shows that the superposition of fifty successive discharges has been achieved with an overall variation of less than 0.3 μs.