Motorized Sample Cell Tracking for Laser Ablation

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Solution Overview

Problem

As specimen chamber sizes for LA-ICP-MS and LA-ICP-OES increase, efficient collection of specimen material becomes more challenging, and existing methods for maintaining the position of a sample collection cell relative to the laser ablation site are limited in precision and efficiency.

Innovation Solution

A system comprising a specimen stage, a sample capture cell, and a cell-positioning system with various actuators (mechanical, electro-mechanical, hydraulic, pneumatic, piezoelectric, or magnetic) to move the sample capture cell relative to the specimen stage, ensuring precise alignment and efficient collection of specimen material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If specimen chamber size is increased to accommodate larger specimens, then the capacity to handle larger specimens is improved, but the efficiency of specimen material collection deteriorates

Engineering Contradiction:

Improvespecimen chamber volumeVSAvoidspecimen material collection efficiency

Core Design Contradiction:

Volume of moving objectVSProductivity

Solution Approach 1:

The sample capture cell is made movable rather than fixed, allowing it to dynamically track and follow the laser ablation site as the laser moves across the specimen surface. This dynamic positioning capability enables efficient collection of specimen material throughout the entire specimen area, resolving the contradiction between large chamber volume and collection efficiency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

A feedback control system is implemented where the position of the laser ablation site is continuously monitored and used to control the position of the sample capture cell. The cell-positioning system receives position information and automatically adjusts the cell location to maintain optimal alignment with the laser ablation site, ensuring high collection efficiency regardless of chamber size.

Inventive Principle:

Principle #23Feedback

2Device complexity

If conventional fixed positioning methods are used for the sample capture cell, then the system complexity is reduced, but the precision of alignment with the laser ablation site deteriorates

Engineering Contradiction:

Improvepositioning system complexityVSAvoidalignment precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces complex mechanical positioning mechanisms with a combination of magnetic coupling and feedback control. The magnetic coupling provides stable positioning through magnetic fields rather than mechanical contacts, while the feedback control system uses electronic signals to maintain precise alignment, reducing mechanical complexity while improving precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

A magnetic field is introduced as an intermediary between the sample capture cell and the external reference magnet. This magnetic coupling allows for precise positioning and tracking without direct mechanical connections, simplifying the mechanical structure while maintaining high alignment precision through the magnetic interaction.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If magnetic coupling is used to maintain the sample capture cell position, then the ease of operation is improved, but the reliability of position maintenance deteriorates

Engineering Contradiction:

Improvecell positioning easeVSAvoidposition maintenance reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

A feedback control system is implemented where the actual position of the sample capture cell is continuously monitored and compared with the desired position. The system automatically makes corrections to maintain reliable positioning, combining the ease of magnetic coupling operation with the reliability of active control to ensure consistent position maintenance.

Inventive Principle:

Principle #23Feedback

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 enables precise and efficient collection and transport of specimen material from the laser ablation site to the analysis system, improving the accuracy and reliability of compositional analysis.

Implementation Method 1

One method employs a noncontact magnetic coupling, through a window in the specimen chamber, between the secondary volume and a fixed reference magnet outside the specimen chamber

Methodology Applied

Scientific EffectMagnetic coupling: Magnetism

Implementation Method 2

ablating a portion of the specimen with one or more laser pulses to generate a plume containing particles and/or vapor, ejected or otherwise generated from the specimen

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentUS11353379B2Motorized tracking of sample cell within specimen chamber and methods of using the same

Publication Date: 2022.06.07 ELEMENTAL SCI LASERS LLC

AI summary

A sampling apparatus (100) employs a cell-positioning system to move a sample capture cell (138) relative to a specimen positioning system (124). The cell-positioning system may be controlled to move sample capture cell (138) opposite to movement of the specimen positioning system (124) to maintain alignment of the sample capture cell (138) with an optical path of a laser beam of a sample generator (108). Alternatively or additionally, the cell-positioning system may be controlled to move sample capture cell (138) in response to alignment deviation of a reference beam on a quadrant detector (404).