Reducing plasma formation in an ion pump
AssigneeEdwards Vacuum LLC
InventorsEvan Privet, Marcus Hans Robert Thierley
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Abstract
An ion pump controller configured to alternate between increasing and decreasing a potential difference between an anode and a cathode of an ion pump multiple times during the starting of pumping.
Claims12
An ion pump controller configured to alternate between increasing and decreasing a potential difference between an anode and a cathode of an ion pump multiple times during the starting of pumping, so as to limit formation of plasma in a pumping chamber of the ion pump while causing ions near the anode to move toward the cathode,
- wherein the ion pump controller is configured to alternate between increasing and decreasing the potential difference between the anode and cathode until a condition is met and then increases the potential difference between the anode and cathode until the potential difference between the anode and cathode reaches a target potential difference, the condition being whether the potential difference between the anode and the cathode is greater than a threshold.
A method of operating an ion pump, the method comprising:
- increasing and decreasing a potential difference between an anode and a cathode of the ion pump;
- determining that a state of the ion pump has changed;
- and
- in response to the change in the state, increasing the potential difference between the anode and the cathode to a target potential difference,
- wherein the increasing and decreasing the potential difference comprises applying voltage pulses between the anode and the cathode, so as to limit formation of plasma in the ion pump,
- wherein determining that a state of the ion pump has changed comprises determining that the potential difference between the anode and the cathode during a voltage pulse is above a threshold voltage.
An ion pump controller configured to automatically alternate between providing power and not providing power to at least one of an anode and a cathode in an ion pump during startup of the ion pump, so as to limit formation of a plasma in the ion pump,
- wherein the ion pump controller is configured to determine a state of the ion pump and in response to the determined state stop alternating between providing power and not providing power and instead continuously provide power,
- the ion pump controller being configured to determine the state of the ion pump and by determining a voltage between the anode and the cathode when providing power, wherein the ion pump controller stops alternating between providing power and not providing power and instead continuously provides power in response to the voltage between the anode and the cathode becoming greater than a threshold.
Dependencies are inferred from the claim text.