| 摘要 |
PURPOSE:To obtain an ion laser apparatus wherein no noise is generated in a laser output and the filament of a cathode has a long life by lighting the cathode filament by using DC current and periodically changing over the polarity of the DC current. CONSTITUTION:A power supply circuit lights the filament of a cathode 13 by a lighting DC power supply 41, which is connected to the cathode 13 via a polarity changeover switch S1. One terminal of a discharging DC power supply 33 is connected to the cathode 13 via an input terminal changeover switch S2 and an anode 15 is connected to the other terminal of the discharging DC power supply 33. The power supply 41 supplies DC current to the cathode 13 to heat the filament and the power supply 33 applies a voltage to the cathode 13 and the anode 15 to cause a discharge in a discharge tube 1, ionizing and exciting rare gas atoms to perform a laser oscillation. In the laser oscillation, the switch S1 is automatically changed over at constant time intervals to change over the polarity of the voltage applied to the filament. Such operation changes over the potential difference in the filament at constant time intervals and can prevent the deterioration due to plasma from being concentrating at one end. |
