磁石内蔵形正マグネトロン真空計

Abstract

Aiming at elimination of the sudden change and inflection of the discharge current at a pressure, five type magnetron gauges containing a magnet inside of the electrode are investigated. One is a hand drum type magnetron gauge. Others are normal cylindrical magnetron gauges of various sizes. It is found that a normal cylindrical magnetron gauge, which contains rather big magnet inside of the cathode with the magnetic flux density of 0.091 [T] at 1.8 mm from the cathode surface, has wider stable pressure range and discharge voltage range, and shows good linearity of the pressure vs the discharge current characteristics in log-log plots. The sensitivity I/P is 3.96 (at 1 × 10-4 [Pa]) and 0.861.06 (at 1 × 10-6 [Pa]) [10-2 A/Pa], the slope of the pressure vs the discharge current characteristics in the log-log plots is 1.097 (at 1 × 10-4 [Pa]) and 1.684 (at 1 × 10-6 [Pa]) at the discharge voltage of 6 [kV] without any sudden change and inflection of the discharge current. The others also have good linearity of the pressure vs the discharge current characteristics in log-log plots at the discharge voltage of 6 [kV]. But, these gauges have sudden changes and inflections, except for 6 [kV] of the discharge voltages.