The output signals from transducers and are used by {HEAD ~ data processing unit} to compute the total concentration of hydrocarbon gases and {TAIL ~ vapors} and the concentration of methane gas within cells and  
The output signals from transducers and are used by { HEAD ~ data processing unit } to compute the total concentration of hydrocarbon gases and { TAIL ~ vapors } and the concentration of methane gas within cells and
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH