Plasma Ignition Voltage Control via Pressure Adjustment
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Solution Overview
Problem
Conventional plasma ignition devices for inductively coupled plasma ion sources require high initial voltages, resulting in high power consumption despite low total power per pulse, necessitating a method to reduce the voltage required for plasma ignition.
Innovation Solution
A charged particle beam apparatus with a gas introduction chamber, plasma generation chamber, coil, electrode, and detection unit that controls voltage based on pressure changes, using Paschen's Law to maintain the voltage within a specific range to achieve plasma ignition at lower voltages, and a controller that adjusts pressure from an ignition pressure to an operating pressure after plasma detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pulse voltage waveform with high initial voltage is used for plasma ignition, then plasma can be ignited, but the voltage required for ignition is high and power consumption increases
Solution Approach 1:
The patent applies parameter changes by adjusting the gas pressure to match Paschen's Law requirements for the applied voltage. By controlling pressure in association with voltage (where voltage is kept between the lower limit value of sparking voltage based on Paschen's Law and twice that value), the system achieves plasma ignition at lower voltages. The controller dynamically adjusts pressure from a first pressure (when plasma is not ignited) to a second pressure (when plasma is ignited), optimizing the pressure-voltage relationship to reduce power consumption while maintaining reliable ignition.
2Reliability
If high voltage is applied to ignite plasma, then plasma ignition is achieved, but the total power per pulse increases
Solution Approach 1:
The patent reduces total power per pulse by changing the voltage parameter to be based on Paschen's Law lower limit value (or up to twice that value) rather than using conventional high voltages. This parameter change, combined with pressure control, achieves plasma ignition at lower power levels. The detection unit confirms ignition at these reduced power levels, validating that reliable plasma ignition is achieved without excessive power consumption.
3Use of energy by moving object
If voltage is controlled based on Paschen's Law with pressure adjustment, then lower ignition voltage is achieved, but system complexity increases
Solution Approach 1:
The patent employs feedback control where the detection unit monitors plasma ignition status and provides information to the controller. The controller then adjusts the pressure in association with the voltage applied to the plasma electrode based on this detection feedback. This closed-loop feedback system automates the complex pressure-voltage coordination required by Paschen's Law, reducing the burden on operators while maintaining optimal ignition conditions with lower voltages.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively suppresses the voltage required for plasma ignition, maintaining stable plasma conditions while reducing power consumption and maintaining plasma performance.
Implementation Method 1
a coil that is wound along an outer circumference of the plasma generation chamber and to which high-frequency power is applied
Implementation Method 2
the controller controls the voltage in association with the predetermined pressure while the voltage is in a range from a lower limit value of a sparking voltage based on Paschen's Law or more to twice the lower limit value or less
Data Source
AI summary
A charged particle beam apparatus according to this invention includes: a gas introduction chamber, into which raw gas is introduced; a plasma generation chamber connected to the gas introduction chamber; a coil that is wound along an outer circumference of the plasma generation chamber and to which high-frequency power is applied; an electrode arranged at a boundary between the gas introduction chamber and the plasma generation chamber and having a plurality of through-holes formed therein; a plasma electrode that is provided apart from the electrode; a detection unit for detecting whether or not the plasma has been ignited in the plasma generation chamber; and a controller that controls, based on the result of detection by the detection unit, a voltage to be supplied to the plasma electrode in association with a predetermined pressure for supplying the raw gas.