Gating circuit for single photon-counting fluorescence lifetime instruments using high repetition pulsed light sources

William R. Laws, David W. Potter, John Clark Sutherland

Research output: Contribution to journalArticle

11 Scopus citations


We have constructed a circuit that permits conventional timing electronics to be used in single photon-counting fluorimeters with high repetition rate excitation sources (synchrotrons and mode-locked lasers). Most commercial time-to-amplitude and time-to-digital converters introduce errors when processing very short time intervals and when subjected to high-frequency signals. This circuit reduces the frequency of signals representing the pulsed light source (stops) to the rate of detected fluorescence events (starts). Precise timing between the start/stop pair is accomplished by using the second stop pulse after a start pulse. Important features of our design are that the circuit is insensitive to the simultaneous occurrence of start and stop signals and that the reduction in the stop frequency allows the start/stop time interval to be placed in linear regions of the response functions of commercial timing electronics.

Original languageEnglish (US)
Pages (from-to)1564-1568
Number of pages5
JournalReview of Scientific Instruments
Issue number10
StatePublished - Dec 1 1984
Externally publishedYes


ASJC Scopus subject areas

  • Instrumentation

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