The assembly includes a source 24 of {HEAD ~ one or more solid materials} such as silicon, {TAIL ~ germanium} and carbon within the chamber 14 
such as
The assembly includes a source 24 of { HEAD ~ one or more solid materials } such as silicon , { TAIL ~ germanium } and carbon within the chamber 14
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH