Some techniques for recording and measuring time-resolved spectra

Methods are considered of recording the time-variation of the spectra of microsecond phenomena. An apparatus is described employing a rotating mirror time-resolving device before the slit of a quartz photographic spectrograph. Writing speeds of up to 5.1 mm/μs are obtained. Consideration of possible calibration techniques involves some preliminary results on reciprocity law failure at very short exposure times. A pulsed calibration source is described in which a continuum at 26 000° K is maintained for 15 μs, and this is used to provide an absolute calibration of the records.