INFICON Composer Gas Concentration Controller - Manual (Page 190)

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Composer Operating Manual
Lorentzian
A term that mathematically describes the shape of a resonance peak.
This instrument uses a Lorentzian curve fit to very accurately determine
the precise frequency of the resonance’s amplitude peak when
operating in the Amplitude Track Mode.
LSB
Least Significant Bit, a term associated with the precision of analog to
digital and digital to analog converters.
Manipulated Variable
The variable that is used to induce changes in the controlled variable.
For typical CVD reactors the control variable normally would be the
carrier gas flow rate through the precursor’s source (bubbler).
MOCVD
Metal-Organic Chemical Vapor Deposition. Frequently used
synonymously with OMVPE.
Molecular Weight
The mass in grams of a mole of a given substance. It is also the weight
in AMU of a single molecule of gas. This is used in the determination of
binary gas concentration by measuring the speed of sound.
Mole Fraction
A way of expressing the Concentration of a mixture that expresses the
relative abundance of each species to the total abundance of all of the
mixture’s constituents as a fraction (usually the decimal equivalent).
Monitor Software
The optional Windows software package providing a common graphical
interface for up to nine instrument systems.
Multiplexer
A hardware interface that allows one of a computer’s RS-232 ports to
be switched among many RS-232 communication links. This allows
many instrument systems to be connected to only one
RS-232 port
NO
Normally Open, referring to relay contacts that stay open until the
relay’s coil is energized
OMVPE
Organometallic Vapor Phase Epitaxy. Frequently used synonymously
with MOCVD
Permeability
The rate at which a gas flows through a material, usually an elastomer.