Laser Ablation Spectroscopy Stabilizing Plasma Plume Precision
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Solution Overview
Problem
Laser-induced breakdown spectroscopy (LIBS) methods for monitoring substrate composition are unreliable due to inconsistent plasma plumes created by pulse lasers, leading to variations in recorded data and failure to match known standards.
Innovation Solution
A laser ablation spectroscopy apparatus that uses a pulsed laser to generate a plasma plume, detected by an optical spectrometer with an intensified charge-coupled device, and a movable stage with x, y, z motors, along with a system computer for synchronizing movements and adjusting sample height, averaging spectral data from multiple ablation sites to ensure consistent results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser induced breakdown optical emission spectroscopy (LIBS) is used to determine composition, then the technique is potentially efficient and economical, but the measurement is unreliable and inexact due to large variation in recorded data
Solution Approach 1:
The patent divides the measurement process into multiple segments by performing multiple laser pulses at the same sample site and collecting spectral data from multiple different sample sites. This segmentation allows for statistical averaging that reduces variation and improves measurement precision while maintaining the efficiency and economy of the LIBS technique.
Solution Approach 2:
The system incorporates feedback mechanisms where the computer controls the positioning stage to move to multiple sample sites based on predetermined patterns, and adjusts measurement parameters based on detected spectral data quality. This feedback loop ensures consistent data collection across multiple measurements to improve reliability.
2Measurement precision
If multiple laser ablations and sample sites are averaged to improve precision, then measurement reliability improves, but the complexity of the apparatus and measurement protocol increases
Solution Approach 1:
The positioning stage is designed to perform multiple functions: it positions the sample for initial measurement, moves to multiple additional sample sites for repeated measurements, and returns to original positions. This multi-functionality allows a single device to handle the complex protocol of multiple ablations and sites without requiring additional specialized equipment.
Solution Approach 2:
The system uses automated computer control to manage the entire measurement protocol, including positioning, laser triggering, spectral data collection, and averaging calculations. This self-service automation reduces the need for manual intervention and complex operational procedures, making the enhanced precision protocol easier to execute.
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 apparatus provides reliable and accurate elemental composition analysis by stabilizing the plasma plume and averaging data, improving the precision of LIBS methods to match known standards and comply with regulations like RoHS.
Implementation Method 1
A pulsed laser is focused on a sample site to generate a plasma plume during a laser ablation process
Implementation Method 2
The plasma plume can be detected with an optical spectrometer having an intensified charge coupled device
Data Source
AI summary
Systems, methods, compositions, and apparatus for laser induced ablation spectroscopy are disclosed. A sample site position sensor, stage position motors operable to move the stage in three independent spatial coordinate directions, and a stage position control circuit can move an analysis sample site to selected coordinate positions for laser ablation. Light emitted from a plasma plume produced with laser ablation can be gathered into a lightguide fiber bundle that is subdivided into branches. One branch can convey a first portion of the light to a broadband spectrometer operable to analyze a relatively wide spectral segment, and a different branch can convey a second portion of the light to a high dispersion spectrometer operable to measure minor concentrations and/or trace elements. Emissions from a plasma plume can be simultaneously analyzed in various ways using a plurality of spectrometers having distinct and/or complementary capabilities.