A Counting Interval Normalization Circuit for Low Signal Level Spectroscopy

Low signal level spectroscopy often requires long data accumulation periods per spectral position. If the data are acquired in digital form, the accumulation period per spectral position must be adjusted to correct for fluctuations in the power output of the excitation source. A circuit has been designed which monitors the source and adjusts the data accumulation period to normalize it to the source power output. The circuit has been applied to Raman scattering experiments to demonstrate its performance.