Apparatus and method for managing a temperature profile using reflective energy in a thermal decomposition reactor

In a thermal decomposition reactor for producing one or more elongated polysilicon bodies by chemical vapor deposition of silicon onto one or more heated silicon filaments in a chamber of a reactor vessel, a device comprising:

• at least one reflector situated in the chamber, the reflector having a reflective surface configured to receive radiant heat energy emitted from an energy emitting region of an elongated polysilicon body grown during chemical vapor deposition onto a silicon filament and reflect at least a portion of the received radiant heat energy to a reflected energy receiving region of the elongated polysilicon body or to a reflected energy receiving region of a second elongated polysilicon body, to thereby supply radiant heat energy to the reflected energy receiving region, the reflective surface having an optical power from 20 to 100 m−1, and wherein the reflector has a frusto-pyramidal configuration.