Adjustable Electrode Arrangement for a Spark Source Mass Spectrograph.

摘要

The design of a convenient electrode mounting for a spark source mass spectrograph must satisfy several requirements. (1) The electrodes must be adjustable to permit compensation for wear. (2) Such adjustment must also keep the spark centered. (3) The spark must be easily observed by the operator. (4) The entire unit should be easily opened for sample changes and easily disassembled for cleaning. (5) The anode must be insulated from ground and the cathode for 30,000 volts, DC. (6) The electrodes must be insulated from each other for as much as 75,000 volts, RF. (7) The entire unit must be vacuum tight. It is, therefore, not surprising that the design of such units has undergone considerable evolution. All designs have used sylphon bellows to permit adjustments, and a Pyrex glass envelope to provide external insulation and visibility. However, the arrangement of the electrodes, the mounting of the various parts, the method of disassembly and the vacuum seal varied. In this paper, the latest design is presented; it is a slight modification of that used on the Mattauch type spectrograph.