Magneto-optical trap ion source for focused beam generation

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Solution Overview

Problem

Existing ion sources, such as liquid metal and gas-phase sources, face limitations in resolution and versatility due to energy spread, chromatic aberration, and sensitivity to positional stability, restricting their application in nanotechnology and ion beam generation.

Innovation Solution

A magneto-optical trap ion source system utilizing a magnetic field and lasers to produce a confined population of low-temperature neutral atoms, which are then ionized and extracted to form a focused ion beam with improved resolution and current range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If liquid metal ion source is used to achieve high brightness and small spot size, then resolution is improved, but energy spread increases causing chromatic aberration

Engineering Contradiction:

Improvespot sizeVSAvoidenergy spread

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

The patent changes the fundamental parameters of the ion source by using a magneto-optical trap to confine neutral atoms at ultra-low temperatures (microkelvin range) before ionization, rather than using a liquid metal emitter at high temperatures. This parameter change in temperature and confinement method reduces the energy spread of the ion beam while maintaining small spot size and high resolution.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If liquid metal ion source is used to achieve high brightness, then current output is improved, but sensitivity to source positional stability increases

Engineering Contradiction:

Improvecurrent outputVSAvoidpositional stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces the mechanical liquid metal emission system with a magneto-optical trap system that uses magnetic fields and laser cooling to confine atoms. This substitution eliminates the mechanical instability and positional drift inherent in liquid metal sources, as the atomic cloud is confined by non-contact magnetic and optical fields, significantly improving positional stability while maintaining high current output.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Temperature

If gas phase source is used to reduce energy spread, then chromatic aberration is reduced, but current output decreases significantly

Engineering Contradiction:

Improveenergy spreadVSAvoidcurrent output

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The patent merges the advantages of gas phase sources (low energy spread from laser cooling) with the high current capability of liquid metal sources by using a magneto-optical trap to confine a large number of neutral atoms and then ionizing them collectively. This combination achieves both low energy spread and high current output, overcoming the limitation of gas phase sources.

Inventive Principle:

Principle #5Merging (Combining)

4Manufacturing precision

If nanometer scale source size is used to achieve high brightness, then resolution is improved, but sensitivity to source positional stability increases

Engineering Contradiction:

Improvesource sizeVSAvoidpositional stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent addresses the positional stability issue by adding temporal dimension to the solution - using laser cooling to reduce the velocity spread of atoms in the trap over time. This allows the system to maintain a stable average position while reducing the effective source size, as the atoms are confined both spatially by the magnetic trap and temporally by the cooling process.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 system achieves high-resolution ion beams with reduced energy spread and increased current output, enabling broader applications and improved performance in nanotechnology tasks like microscopy and material deposition.

Implementation Method 1

a magneto-optical trap having an enclosure, a component for providing a magnetic field, and at least one laser. The magneto-optical trap is adapted to produce a confined population of low temperature neutral atoms within the enclosure

Methodology Applied

Scientific EffectMagneto-optical trap: Magneto-Optic Effects

Implementation Method 2

The magneto-optical trap is adapted to produce a confined population of low temperature neutral atoms within the enclosure

Methodology Applied

Scientific EffectLaser cooling: Laser

Implementation Method 3

The light from the secondary laser ionizes at least a portion of the neutral atoms to thereby form a population of ions

Methodology Applied

Scientific EffectPhotoionization: Photoionisation

Data Source

PatentUS7709807B2Magneto-optical trap ion source

Publication Date: 2010.05.04 GOVERNMENT OF THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SEC OF COMMERCE THE NAT INST OF STANDARDS & TEHCNOLOGY

AI summary

A system and method are disclosed for producing a source of ions, and particularly, a focused ion beam. The system and method use a magneto-optical trap (MOT) to produce a population of neutral atoms. A laser is then utilized to ionize atoms and produce a population of ions. An extraction element is then used to transfer the ions so that they can be used in a wide array of applications.