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Proceedings Paper

Device for measuring the microsecond-component of the induction kinetics of the chlorophyll-fluorescence
Author(s): Bernhard Ruth
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Paper Abstract

The exciatation light intensity 'e provided by a 6 mW He-Ne laser is switched by a combination of an acousto-optical modulator OS and a mechanical shutter MS. A switching-time below 0.3 s and a power density of 10 mW/cm2 at the object are achieved. Two photoinultipliers measure the fluorescence intensities F685(t) and F730(t) at the two peak wavelengths (685 mu and 730 mn), the nieasuring signals are synchronously stored by a transient recorder with a time resolution of 10 p.s and a capacity of 8000 pairs of measuring values and by a computer with a time resolution which is decreased in steps from 200 1L5 to 200 ins within the total measuring time of 5 mm. The combined use of OS and MS ensures the stability of 'e within 5% during the total measuring time. In addition to the peak intensity F0 and the steady-state intensity F5 which are commonly determined b' devices with low time resolution, the initial intensity Fb and its time derivative Db and intensity F1, time tj, and time derivative D of the inflection point can accurately be determined by the device. The ratio R(t) = F730(t)/F685(t) shows an initial value Rb which is similar to the steady-state-value R5 and two minimum values Rml and Rm2 near 10 ms and 15, respectively.

Paper Details

Date Published: 1 August 1990
PDF: 12 pages
Proc. SPIE 1269, Environment and Pollution Measurement Sensors and Systems, (1 August 1990); doi: 10.1117/12.20349
Show Author Affiliations
Bernhard Ruth, Gesellschaft fuer Strahlen- und Umwelftorschung mbH (Germany)

Published in SPIE Proceedings Vol. 1269:
Environment and Pollution Measurement Sensors and Systems
Hans Ole Nielsen, Editor(s)

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