The discharge vessel encloses a discharge space having an ionizable filling which, in addition to Hg, contains a quantity of {HEAD ~ iodide} of Na, Tl, Ho and {TAIL ~ Ca} 
of
The discharge vessel encloses a discharge space having an ionizable filling which , in addition to Hg , contains a quantity of { HEAD ~ iodide } of Na , Tl , Ho and { TAIL ~ Ca }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL