| 摘要 |
A floating plate ion monitoring system and method wherein an ion collector assembly comprises an ion conducting surface and shielding surface in spaced relation, the ion conducting surface being located to receive ion impingement thereon, and wherein a potential is applied to the shielding surface which duplicates and follows the voltage appearing on the ion conducting surface. As a result, the capacitance between the ion conducting surface and the shielding surface is established electrically and independent of the physical configuration of the ion collector assembly. The foregoing is accomplished by providing a unity gain connected operational amplifier and connecting the positive input thereof to the ion conducting surface and the inverting input thereof to the shielding surface. An indicator connected to the amplifier output monitors the voltage on the ion conducting surface. A voltage reference is applied to the electrically established capacitance so that the voltage rating thereof need not be equal to or greater than the limits of voltage appearing on the ion conducting surface. The magnitude of the applied voltage reference can be varied in a manner varying the magnitude of the electrically established capacitance.
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