In some embodiments, another light source 314 and {TAIL ~ associated optics} may be provided by {HEAD ~ an analyzer} 
In some embodiments , another light source 314 and { TAIL ~ associated optics } may be provided by { HEAD ~ an analyzer }
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD