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Reduction of PMT Signal-Induced Noise in Lidar ReceiversSignal-induced noise is generated when a photomultiplier tube (PMT) is subjected to an intense light pulse. The PMT signal does not return to the dark current level after the signal is removed, but decays slowly (i.e., signal-induced noise). This is of practical significance for DIAL (Differential Absorption lidar) measurements where signal-induced noise decays are superimposed on the on-line (absorption) and off-line signals. Errors in the ozone density calculation result for stratosphere measurements. Other researchers have implemented mechanical choppers that block the intense pulse which may be from near field return scattering or scattering from a cloud. This configuration cannot be implemented for the DIAL system employed for aircraft measurements since the on-line and off-line pulses are 300 microseconds apart. A scheme has been developed in this study to electronically attenuate the signal induced noise. A ring electrode, external to the PMT photocathode, is utilized to perturb the electron trajectories between the photocathode and the first dynode. This effect has been used for position sensitive PMTs and suggested for gating PMTS.
Document ID
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Williamson, Cynthia K.
(NASA Langley Research Center Hampton, VA United States)
DeYoung, Russell J.
(NASA Langley Research Center Hampton, VA United States)
Date Acquired
August 18, 2013
Publication Date
July 1, 1998
Publication Information
Publication: Nineteenth International Laser Radar Conference
Issue: Part 2
Subject Category
Instrumentation And Photography
Distribution Limits
Work of the US Gov. Public Use Permitted.
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