A technique is disclosed for detecting a turbo pump drive state in a
tendetron accelerator that accelerates an ion beam to implant ions onto a
semiconductor wafer. In particular the method of detecting a turbo pump
driving state in the accelerator includes the steps of detecting a current
applied to the turbo pump in the accelerator; converting the detected
current to an optical signal to transmit it through an optical fiber;
converting the optical signal transmitted through the optical fiber to an
electric signal; displaying the current value of the converted electric
signal; comparing the current value of the converted electric signal with
a setting current value to generate an interlocking signal when the
current value is out of a given range of the setting current value; and
cutting off a power supply of the tendetron accelerator in accordance with
the interlocking signal.
