LIBS Analyzer Sample Presence Detection Using Pre-Firing Fluorescence
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LIBS systems often require higher power lasers to detect certain elements, which can lead to regulatory requirements and safety concerns due to the potential for eye damage, necessitating the development of an eye-safe laser system that ensures accurate targeting and prevents unnecessary laser shots.
Innovation Solution
A LIBS system with a controller subsystem that initiates a laser pump sequence only when the laser is aimed at a sample, using low-intensity pre-firing radiation to determine sample presence and halting the sequence if not detected, thereby preventing laser discharges into air and ensuring accurate spectral analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a higher power laser is used to detect certain elements and achieve lower detection limits, then measurement precision is improved, but safety risks increase due to potential eye damage and regulatory requirements
Solution Approach 1:
The system performs preliminary detection using low-intensity pre-firing radiation (fluorescence emitted during laser pumping) to verify sample presence before initiating the high-power laser discharge. This preliminary action prevents high-power laser shots when no sample is present, thereby maintaining measurement precision while eliminating safety risks associated with untargeted high-power laser emission
Solution Approach 2:
The patent introduces an intermediary detection mechanism using the fluorescence emitted during the laser pump cycle as a mediator. This intermediate signal serves as a safety check between the control system and the high-power laser discharge, allowing the system to verify target presence without directly exposing operators to harmful high-power laser radiation
2Measurement precision
If a higher power laser is used to achieve lower detection limits, then measurement precision is improved, but device complexity increases due to regulatory requirements for eye protection and safety protocols
Solution Approach 1:
The system performs preliminary detection using low-intensity pre-firing radiation (fluorescence emitted during laser pumping) to verify sample presence before initiating the high-power laser discharge. This preliminary action prevents high-power laser shots when no sample is present, thereby maintaining measurement precision while eliminating safety risks associated with untargeted high-power laser emission
Solution Approach 2:
The laser pump cycle itself generates the detection signal (fluorescence) needed for safety verification. The system uses its own operational process to provide the safety check, eliminating the need for separate detection devices or complex external safety systems. This self-service approach maintains detection precision while reducing device complexity
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 effectively prevents unnecessary laser discharges, ensuring safe operation and accurate elemental detection while maintaining a Class I laser classification, reducing the need for special training or equipment and enhancing detection capabilities with higher power lasers.
Implementation Method 1
analyze low intensity pre-firing radiation (fluorescence emitted by the laser rod during energization or "pumping" that occurs 10's to 100's of microseconds before the laser discharge)
Implementation Method 2
a laser configured to produce a plasma on a sample
Implementation Method 3
a spectrometer responsive to radiation emitted from the plasma
Data Source
AI summary
A LIBS analyzer and method includes a laser configured to produce a plasma on a sample at a focal point on the sample and a spectrometer responsive to radiation emitted from the plasma and configured to produce an output spectrum. A detector is positioned to detect low intensity pre-firing radiation produced by the laser and reflected off the sample from the focal point. The intensity of the low intensity pre-firing radiation is compared to a predetermined minimum and the laser pump sequence is halted if the intensity of the low intensity pre-firing radiation is less than the predetermined minimum.