An automatic flash photolysis system for the measurement of absorption decays and transient difference spectra is described. The apparatus performs a digital measurement of the light transmitted by the sample and a few on-line preprocessing operations on the measured data, such as the digital averaging of the signal and the computation of the change in absorbance. A boxcar averager, used as a gated integrator, constitutes the sampling head of the apparatus. A microprocessor-based acquisition and control unit performs a digital conversion of the value sampled by the boxcar, provides an on-line preprocessing of the data, and supervises every operation required by the measurement process. This unit is interfaced to a personal computer which allows a friendly interaction with the operator as well as the on-line display of the data. The electronic instrumentation features a time resolution of a few nanoseconds, with a boxcar averager as input head, and of a few hundreds of picoseconds, with a sampling oscilloscope as input head.
A. Longoni and G. Ponterini, "Real-Time Acquisition and Preprocessing of Kinetic and Spectroscopic Data in Laser Flash Photolysis," Appl. Spectrosc. 40, 599-605 (1986)