SiPM Time-Gated LIBS System for Portable Elemental Analysis
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Solution Overview
Problem
Current LIBS systems face challenges with bulky, expensive ICCD cameras and limited versatility of line cameras, particularly in achieving sensitive time-resolved measurements with low energy per pulse and high repetition rate laser sources, which restricts their application beyond laboratory settings.
Innovation Solution
The use of a silicon photomultiplier (SiPM) in a portable LIBS system for time-gated photon counting, combined with a low energy pulsed fiber laser and wavelength-converting coatings, enables efficient detection of spectral lines with improved sensitivity and robustness, overcoming the limitations of ICCD cameras.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ICCD cameras are used for time-resolved detection in LIBS systems, then measurement sensitivity and dynamic range are improved, but system weight, size, and cost increase significantly
Solution Approach 1:
The patent extracts the time-gating function from the detector itself and implements it through external optical shutters (acousto-optic or electro-optic modulators) placed in the optical path. This separation allows the use of simpler, lighter detectors while maintaining time-resolved measurement capabilities through the external gating mechanism.
Solution Approach 2:
The patent employs a photomultiplier tube (PMT) that can operate in multiple modes (continuous and time-gated) by simply adjusting the shutter timing, making the detection system versatile for different measurement requirements without needing specialized detectors for each mode.
2Measurement precision
If ICCD cameras are used for time-resolved detection in LIBS systems, then measurement sensitivity and dynamic range are improved, but system cost increases significantly
Solution Approach 1:
The patent extracts the time-gating function from the detector itself and implements it through external optical shutters (acousto-optic or electro-optic modulators) placed in the optical path. This separation allows the use of simpler, lighter detectors while maintaining time-resolved measurement capabilities through the external gating mechanism.
Solution Approach 2:
The patent replaces the expensive ICCD camera with a combination of a relatively inexpensive photomultiplier tube and programmable optical shutters, achieving comparable measurement sensitivity at a fraction of the cost by using standard, readily available components.
3Loss of information
If line cameras are used for spectral detection, then spectral information can be obtained, but time-resolved measurement capability and measurement sensitivity are limited
Solution Approach 1:
The patent segments the spectral detection into multiple wavelength channels using a diffraction grating that disperses light across the PMT's spectral response range, allowing simultaneous detection of multiple spectral lines while maintaining time-resolved capability through the gated detection approach.
Solution Approach 2:
The patent introduces a diffraction grating as an intermediary between the plasma source and the PMT detector, which disperses the emitted light into its spectral components and directs them to the detector, enabling spectral analysis without requiring a complex spectral camera.
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 configuration allows for sensitive and portable LIBS systems capable of detecting elements with low LOD values, suitable for field applications, by enhancing dynamic range and reducing system weight and cost, while maintaining analytical performance.
Implementation Method 1
irradiating the sample using repetitive laser pulses to create a plasma that emits light representative of the sample's one or more constituent elements
Implementation Method 2
create a plasma that emits light representative of the sample's one or more constituent elements
Implementation Method 3
detecting, via said SiPM, said spectral portion of said emitted light within said predefined wavelength interval
Implementation Method 4
combined with a low energy pulsed fiber laser and wavelength-converting coatings
Data Source
AI summary
Described are various embodiments of a system, method and device for laser induced breakdown spectroscopy (LIBS). In some embodiments, the LIBS system comprises a silicon photomultiplier (Si PM) operated in a time-gated photon counting mode. Some such embodiments allow for the provision of a portable LIBS device. Also provided are embodiments for the measurement of constituent carbon, gold and/or other precious metal group elements in a target sample.