Inductively Coupled Plasma Ion Source High Voltage Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inductively-coupled plasma (ICP) sources face challenges in high voltage isolation and cooling, leading to design complexities such as gas-phase discharges and heat management, which complicate the efficient operation and safety of plasma sources.
Innovation Solution
The implementation of a Faraday shield encapsulated in solid dielectric media and the use of static fluids for high voltage isolation, combined with integrated heat pipes for cooling, addresses the issues of electrical isolation and heat dissipation, allowing for efficient plasma operation and reduced capacitive coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas is brought into the high voltage plasma chamber to replenish gas, then the plasma can maintain ionization, but gas phase discharge (arcing) may occur which would damage the system
Solution Approach 1:
A liquid with high dielectric constant is introduced as an intermediary medium between the gas supply system and the high voltage plasma chamber. This liquid prevents gas phase discharge by providing electrical isolation, while still allowing gas to reach the plasma chamber through the liquid medium without causing arcing.
Solution Approach 2:
The patent changes the physical state and electrical properties of the medium by using a liquid with high dielectric constant instead of gas or air. This parameter change (from gas to liquid with different dielectric properties) prevents breakdown and arcing while maintaining the ability to supply gas to the plasma chamber.
2Use of energy by moving object
If RF coils are placed close to the plasma for efficient power transfer, then power transfer efficiency improves, but maintaining the coils at high plasma potential complicates the power supply design and increases cost
Solution Approach 1:
The liquid with high dielectric constant serves as an intermediary that allows RF coils to be positioned close to the plasma for efficient inductive coupling, while the liquid provides electrical isolation that enables the coil power supply to be grounded rather than floating at high potential, simplifying the power supply design.
Solution Approach 2:
The liquid creates an electrically inert environment between the RF coils and the plasma, allowing the coils to operate at ground potential while still efficiently coupling power to the plasma through the liquid medium, thus avoiding the complexity of high voltage power supply design.
3Reliability
If a grounded Faraday shield is located close to the dielectric plasma container to reduce capacitive coupling, then capacitive coupling is reduced, but gas phase discharge may occur if air or low dielectric constant gas is trapped between the shield and container
Solution Approach 1:
The liquid with high dielectric constant is placed as an intermediary between the grounded Faraday shield and the dielectric plasma container, eliminating the need for air or low dielectric constant gas in this region. The liquid prevents gas phase discharge while maintaining the electrical shielding function.
Solution Approach 2:
The patent changes the dielectric constant of the medium between the Faraday shield and plasma container from low (air) to high (liquid), which prevents electrical breakdown and eliminates the harmful effect of gas phase discharge while preserving the capacitive coupling reduction benefit.
4Productivity
If the plasma source is made more compact and powerful for efficient beam formation, then beam formation efficiency improves, but the source generates more heat requiring better cooling
Solution Approach 1:
The patent uses a liquid cooling system where coolant flows through channels in contact with the plasma source, efficiently removing heat generated by compact and powerful plasma operation. The liquid medium provides both cooling and electrical isolation functions.
Solution Approach 2:
The system discards heat from the plasma source by transferring it to a coolant liquid, which carries the heat away from the compact plasma source. This allows the source to maintain high power density for efficient beam formation while the cooling system handles the thermal load.
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
This solution provides effective high voltage isolation and efficient cooling, enabling the creation of a dense, quiescent plasma source that maintains high potential while preventing gas-phase discharges and overheating, thus enhancing the design and operational safety of ICP sources.
Implementation Method 1
the fluid has a dielectric constant greater than 5
Implementation Method 2
a heat pipe for cooling the plasma chamber
Implementation Method 3
The RF antenna provides energy to maintain the gas in an ionized state within the chamber
Implementation Method 4
a portion of the liquid is evaporated by heat from the plasma chamber creating a vapor
Data Source
AI summary
An inductively-coupled plasma source for a focused charged particle beam system includes a plasma chamber and a fluid that is not actively pumped surrounding the plasma chamber for providing high voltage isolation between the plasma chamber and nearby parts which are at ground potential, such as a conductive shield. One or more cooling devices cool the plasma chamber by using evaporative cooling and heat pipes to dissipate the heat from the plasma chamber into a surrounding environment.