| 摘要 |
A vitreous silica crucible manufacturing apparatus includes a plurality of carbon electrodes configured to heat and melt raw material powder by arc discharge, and a value of a ratio R2/R1 of a diameter R2 of a front end of each of the carbon electrodes to a diameter R1 of a base end is set in a range of 0.6 to 0.8. Each carbon electrode has a diameter reduction portion formed at a front end position and reduced in diameter from a diameter R3 of a base end side to the diameter R2 of the front end. When a length of the diameter reduction portion is L1, the diameter of the front end is R2, the diameter of the base end is R1, an angle between the axis lines of the carbon electrodes is &thetas;1, and X=(R1−R2)/2, a value of L1−(X/tan(&thetas;1/2)) is set in a range of 50 to 150 mm.
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