{TAIL ~ A solid material} or {HEAD ~ combination} of materials is evaporated in the chamber to form vapor 
{ TAIL ~ A solid material } or { HEAD ~ combination } of materials is evaporated in the chamber to form vapor
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH