Method for the reduction of signal-induced noise in photomultiplier tubes.
A new method to reduce photomultiplier tube detector signal-induced noise (SIN) in a lidar system is successfully demonstrated. A metal ring electrode placed external to the photomultiplier tube photocathode is pulsed during the intense near-field lidar return with a potential between 15 and 500 V, resulting in a significant reduction in SIN. The effect of the metal ring voltage on the decay time constant and the magnitude of a simulated lidar signal is presented. Optimal experimental conditions for the use of this device in lidar receivers, such that the lidar decay time constant is not affected, are determined. Mechanisms for this SIN suppression system are discussed in detail, and data were recorded to show that the voltage on the metal ring functions by altering the photomultiplier electron optics.
Williamson
C K
CK
Atmospheric Science Research, NASA Langley Research Center, Hampton, Virginia 23681, USA.
De Young
R J
RJ