{HEAD ~ a CdS crystal} annealed in {TAIL ~ an inert atmosphere} at a temperature and for a period of time to provide substantially maximum acoustic attenuation at the operating frequency of the crystal; and 
annealed in
{ HEAD ~ a CdS crystal } annealed in { TAIL ~ an inert atmosphere } at a temperature and for a period of time to provide substantially maximum acoustic attenuation at the operating frequency of the crystal ; and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH