PURPOSE: To reliably detect discharge and to minimize a change in pressure, by a method wherein, through the detection of discharge, the discharge in a vacuum bulb to be measured is caused to suspend after a given period of time has elapsed.
CONSTITUTION: A magnetic field generating coil 2 is activated, through a power source 4, from which the magnetic field generating coil 2 is energized, and the magnetic fields are applied around vacuum bulb 1 to be measured. With a high- voltage generating circuit 3 actuated, a control circuit 6 applies a high-voltage to one of electrodes of the vacuum bulb 1 to be measured whose contact is caused to part. A magnetron discharge is generated in the vacuum bulb 1, and is detected by means of a discharge current measurement circuit 5. The signal is sent to a control circuit 6, and causes the high-voltage generating circuit 3 to suspend working after a delay time, during which a discharge current is brought into a stable state, has elapsed. This finds the degree of vacuum from a discharge current value.
MIYAHARA KUNIO
SATAKE MATSUO
| JPS4941836A | 1974-04-19 |