Teledyne GAS LASER Operator's Manual page 8

GAS LASER
DEFINITIONS
Doc No. 16162 Rev A, GAS LASER Operator Manual
Beam Skip
Occurs when the IR beam jumps between a near object and a far object.
This may cause a false detection. This can also occur on highly reflective
surfaces (windows, water, ice, etc.).
Dark Zone
An area not being scanned due to an obstruction. This may be an elevation
change, the side of a building, behind a curb, etc.
DMD (Digital Methane Detection)
An advanced detection mode which, when activated, will only alert the
operator when there is a probable detection of methane.
Footprint
The surface area covered by the IR beam, which increases with distance. At
100 ft., this area is 22" in diameter when shined against a vertical back-
ground.
Infrared (IR)
Optical radiation with wavelengths longer than those of the visible spec-
trum.
Laser Calibration Drift
A normal characteristic of tunable diode lasers is that the wavelength
calibration can drift slowly over time. The Gas Laser has a built in Self-Test/
Calibration feature to automatically maintain proper calibration.
PPM-M (Parts Per Million Meter)
The product of the methane concentration times the thickness of the
plume.
Spotter Laser
The green, blinking laser which guides the operator as to the location of
the IR beam. This laser can be activated through the left button located on
the keypad.
Tunable Diode Laser Absorption Spectroscopy
A method of gas detection that utilizes a laser that, when directed through
a cloud of methane, will be partially absorbed by the gas and the return
signal can then be analyzed for gas concentration.
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Manuel de l'opérateur
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