Smallest detectable partial pressure

The smallest detectable partial pressure is defined as a ratio of noise amplitude to sensitivity  

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Smallest detectable partial pressure ratio (concentration)... 

The smallest detectable partial pressure for helium is Pmin He" pumping speed for helium would be... 

Detection limit. The detection limit of an instrument should be differentiated from its sensitivity. The detection limit reflects the smallest flow of sample or the lowest partial pressure that gives a signal that can be distinguished from the background noise. One must specify the experimental conditions used and give the value of signal-to-noise ratio corresponding to the detection limit. 

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