The individual wavelengths preferably will be directed to impinge on {HEAD ~ a photo diode array} 21, which serves as {TAIL ~ means} to amplify the intensity of individual wavelengths for accurate analysis 
serves as
The individual wavelengths preferably will be directed to impinge on { HEAD ~ a photo diode array } 21 , which serves as { TAIL ~ means } to amplify the intensity of individual wavelengths for accurate analysis
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH