Ion Collection Target Biasing to Minimize Sputtering
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Solution Overview
Problem
Existing ion beam systems inefficiently retain ions in substrate materials, leading to sputtering, sublimation, or scattering, and do not facilitate high-efficiency collection for applications like healthcare.
Innovation Solution
An ion production system with an ion source, extraction electrodes, and a target held at a voltage of the same polarity as the ions, reducing kinetic energy to thermal energy upon impact, minimizing sputtering and maximizing ion collection as a film on the target.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high extraction energy is used to extract ions from the ion source, then ion beam intensity is improved, but ion retention in the substrate material deteriorates due to sputtering, sublimation, or scattering
Solution Approach 1:
The target is pre-charged to a voltage that matches the ion beam extraction energy before the ions arrive. This preliminary voltage setup creates an opposing electric field that immediately decelerates the incoming ions, converting their kinetic energy to potential energy and preventing sputtering and scattering events that would occur with direct high-energy impact.
Solution Approach 2:
The invention converts the harmful high kinetic energy of the incoming ion beam into useful electrical potential energy by having the ions climb the voltage gradient of the pre-charged target. This energy conversion process naturally decelerates the ions to near-zero kinetic energy upon reaching the target surface, transforming what would be destructive energy into a controlled deposition process.
2Power
If high extraction energy is used to extract ions from the ion source, then ion beam intensity is improved, but heat load on the target increases
Solution Approach 1:
The high kinetic energy that would otherwise manifest as heat upon impact is instead converted into electrical potential energy as ions climb the voltage gradient of the charged target. This energy transformation prevents the direct conversion of kinetic energy to thermal energy, dramatically reducing the heat load on the target while maintaining high ion beam intensity.
Solution Approach 2:
The invention replaces the mechanical impact process (where kinetic energy directly converts to heat upon collision) with an electromagnetic energy conversion process. Ions are decelerated by the electric field of the charged target rather than by physical collision, substituting a thermal-mechanical process with an electromagnetic one that does not generate the same heat load.
3Power
If high extraction energy is used to extract ions from the ion source, then ion beam intensity is improved, but ion collection efficiency deteriorates
Solution Approach 1:
The target is pre-charged to the appropriate voltage before ion beam arrival, creating the decelerating electric field in advance. This preliminary preparation ensures that when high-intensity ions arrive, they immediately encounter the opposing field that guides them to gentle deposition, maximizing collection efficiency without requiring reduction of beam intensity.
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
High-efficiency collection of ions as a constituted material, reducing downtime and maintenance, and enhancing ion utilization for healthcare applications.
Implementation Method 1
a voltage source coupled to the target and configured to hold the target at a first voltage having the first polarity. The first voltage causes a kinetic energy reduction of the ions at the extraction energy
Implementation Method 2
extraction electrodes configured to extract the ions from the ion source as an ion beam having an extraction energy
Implementation Method 3
When the effective energy becomes similar or lower than the thermal energy of the evaporated ions, the ions may be deposited as thin films on substrates, thus maximizing the capture of ions
Data Source
AI summary
A system includes an ion source configured to generate ions having a first polarity, one or more extraction electrodes configured to extract the ions from the ion source as an ion beam having an extraction energy, a mass resolving slit or aperture configured to select a desired isotope from the ion beam such that a desired isotopic ion beam passes through the mass resolving slit or aperture, a target positioned relative to the mass resolving slit or aperture so that the desired isotopic ion beam is incident on the target, and a voltage source coupled to the target and configured to hold the target at a first voltage having the first polarity. The first voltage causes a reduction of the extraction energy as the desired isotopic ion beam approaches the target to minimize sputtering and maximize collection of the ions on the target to reconstitute an ionized material.