Versatile nanosecond fluorometer employing a boxcar averager

A nanosecond pulse fluorometer which employs a boxcar averager and has the following novel features is described: (a) It achieves a short data acquisition time with a noise reduction factor in excess of 103; (b) corrects for baseline drift and for exciting light intensity fluctuations; and (c) employs intense nanosecond optical pulses which cover the ultraviolet to the far visible wavelength range. Examples of the performance of the fluorometer, including the measurement of sub-nanosecond fluorescence decay times, are presented. The effect of the variation of the time profiles of the exciting light pulses with their wavelength on the accurate determination of fluorescence decay times has been investigated for a variety of flashing gases over a wide range of pressures.