an evaporation detector arranged in said furnace and detecting at least any one of {HEAD ~ the amount} of evaporation of impurity from said crucible, the temperature above said molten liquid, or the pressure inside of {TAIL ~ said furnace}; and 
an evaporation detector arranged in said furnace and detecting at least any one of { HEAD ~ the amount } of evaporation of impurity from said crucible , the temperature above said molten liquid , or the pressure inside of { TAIL ~ said furnace } ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH