Graphene-Based Filament Work Function Tuning for Ionization

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Thermal ionization mass spectrometry (TIMS) faces low ionization efficiency, particularly for elements with high first ionization potentials, limiting sample materials and requiring extensive preparation to avoid contamination, which restricts the technique's capabilities.

Innovation Solution

The use of graphene-based thermal ionization filaments, which can be doped or chemically modified, significantly enhances ionization efficiency by tuning the work function and allowing for improved filament geometries through additive manufacturing, resulting in a 2-3 order of magnitude increase in ionization efficiency compared to traditional metal filaments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional metal filaments are used for thermal ionization, then the system structure is simple and easy to manufacture, but ionization efficiency is low (only 0.1-0.2% for elements like uranium and plutonium)

Engineering Contradiction:

Improveionization efficiencyVSAvoidfilament manufacturing complexity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent applies composite materials by combining graphene-based materials (graphene, graphene oxide, or reduced graphene oxide) with metal substrates to create hybrid filaments. This composite structure leverages the high ionization efficiency of graphene while maintaining the structural integrity and manufacturability of metal filaments, achieving 2-3 orders of magnitude increase in ionization efficiency compared to traditional metal filaments alone

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters of the filament by introducing graphene-based coatings that modify the surface properties and work function of the filament. This parameter change enables significantly improved ionization efficiency while the underlying metal substrate maintains the filament's mechanical properties and ease of manufacture

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If elements with large first ionization potentials are analyzed using traditional TIMS, then the analysis capability is limited, but extensive sample preparation is required to achieve sufficient ionization

Engineering Contradiction:

Improveelement analysis capabilityVSAvoidsample preparation requirements

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the work function parameter of the filament through graphene-based coatings, which enables efficient ionization of elements with large first ionization potentials. This parameter modification expands the adaptability of TIMS to analyze previously difficult elements without requiring extensive sample preparation or purification steps

Inventive Principle:

Principle #35Parameter changes

3Productivity

If only 0.1-0.2% of analytical sample is ionized in traditional TIMS, then the ionization efficiency is low, but the system requires pure samples free from contaminate elements and isobars

Engineering Contradiction:

Improveionization efficiencyVSAvoidsample purity requirements

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The use of graphene-metal composite filaments dramatically increases ionization efficiency to 2-3 orders of magnitude higher than traditional filaments. This improvement means that much smaller fractions of the sample need to be ionized to achieve the same signal intensity, thereby reducing the impact of contaminant elements and isobars and relaxing the stringent sample purity requirements of traditional TIMS

Inventive Principle:

Principle #40Composite materials

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 approach enables more efficient ionization of samples, allowing for the analysis of smaller sample sizes and previously difficult-to-analyze elements, expanding the capabilities of TIMS by improving ionization efficiency and reducing sample preparation requirements.

Implementation Method 1

resistively heating the graphene TI filament

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

resistively heating the graphene TI filament to a temperature at which atoms of the sample are desorbed and ionized

Methodology Applied

Scientific EffectThermal desorption: Desorption

Implementation Method 3

Thermal ionization utilizes resistive heating of a filament to desorb and spontaneously ionize elemental species from a solid sample located in contact with the filament

Methodology Applied

Scientific EffectThermal ionization: Ionisation

Data Source

PatentUS20180240637A1Graphene/Graphite-Based Filament for Thermal Ionization

Publication Date: 2018.08.23 BATTELLE SAVANNAH RIVER ALLIANCE LLC

AI summary

Methods and systems for thermal ionization of a sample and formation of an ion beam are described. The systems incorporate a thermal ionization filament that is formed of a graphene-based material such as graphite, graphene, graphene oxide, reduced graphene oxide or combinations thereof. The filament material can be doped or chemically modified to control and tune the work function of the filament and improve ionization efficiency of a system incorporating the filament. The systems can be utilized in forming an ion beam for target bombardment or analysis via, e.g., mass spectrometry.