Hopper for use in charging semiconductor source material

A hopper for use in charging semiconductor source material to a crucible of a crystal pulling apparatus which produces monocrystals by the Czochralski method, the crystal pulling apparatus including a pulling chamber, a growth chamber, an isolation valve operable to seal the growth chamber from the pulling chamber, and a crucible in the growth chamber, a hopper being sized and shaped for reception in the crystal pulling apparatus, the hopper comprising a bin constructed for containing a quantity of semiconductor source material, the bin having an opening in its bottom for delivery of the semiconductor source material from the bin to the crucible, a stopper constructed for closing the opening to prohibit passage of semiconductor source material from the bin, a stopper actuating mechanism for moving the stopper between a closed position and an open position, and a connector attached to the hopper constructed for temporarily mounting the hopper in the crystal pulling apparatus.