Thermal shock-resistant rapid-heating CaF2 crystal annealing apparatus

The invention relates to a CaF2 crystal annealing apparatus. A precise annealing method is usually adopted under vacuum conditions to improve the stress distribution in the crystals when the diameter of growing CaF2 crystals is not lower than 50mm or requirements on the quality of the growing crystals, especially the stress birefringence index, are high in order to reduce birefringence caused by the stress in the crystals. A double heating system is designed in a vacuum annealing furnace to reduce the electric energy consumption in the crystal annealing process and improve the annealing effect, and isothermal surface of the temperature field of the inner heating system parallels to the large surface of crystal blanks to realize rapid heating. The outer heating system is positioned outside an inner heat insulation layer and is used for slowly cooling, so the above design improves the inertness of a temperature field formed by a crucible, crystals and a crucible filler, effectively resists thermal shock of environment and improves the stability of the crystal cooling process; and a fluorating agent and CaF2 polycrystalline powder are added to the crucible, so the heating inertness is improved, and oxidation of the crystals is prevented.