Voltage or current control of thyratron for gas-laser switching - determining error pulse rate or repetition rate of gas laser and setting operating voltage or current accordingly

摘要

The laser (10) is pulsed by application of voltage to its discharge electrodes (12,12') from a pulse generator (16) triggered by the thyratron (Th) whose operation depends critically on the cathode heater voltage (UH) and the heating voltage (UR) applied to its gas reservoir. These voltages are varied with the firing angle by a phase control circuit (20) feeding a transformer (22), rectifier (24) and buffer (26). A regulator (28) compares the instantaneous voltages with prescribed values stored in a central control unit (30). A trigger unit (32) acts on the grid (Gi) of the thyratron in response to signals from an optical pulse sensor (38). USE/ADVANTAGE - For TEA-CO2 and excimer lasers. Operation of laser is improved and lifetime of thyratron is prolonged.