Modulated Spark Waveform for Precise Optical Emission Spectroscopy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional spark generators for optical emission spectroscopy lack control over the current waveform, leading to poor reproducibility and accuracy in elemental analysis, particularly for trace elements and alloying elements in metal samples, and CCD detectors experience deterioration due to intense UV light from single peak spark sources.
Innovation Solution
A spark generator producing a current waveform with a first modulated portion of high current and high gradient peaks of variable amplitude and inter-peak duration, and a second modulated portion of low current and low gradient without peaks, allowing for controlled energy delivery and reduced detector deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single high current peak is used for sample evaporation and excitation, then the evaporation efficiency is improved, but the measurement precision deteriorates due to poor spark reproducibility
Solution Approach 1:
The single high current peak is segmented into multiple high current peaks of variable amplitude and inter-peak duration within the first modulated portion. This segmentation allows the sample evaporation process to be divided into multiple stages, improving both evaporation efficiency and spark reproducibility for better measurement precision
Solution Approach 2:
The spark generator applies periodic modulation to the current waveform, creating alternating high and low current periods. The first modulated portion contains multiple high current peaks for evaporation, while the second modulated portion provides low current for stable excitation, achieving both high productivity and measurement precision
2Illumination intensity
If a single high current peak is used to excite atoms in vaporised sample, then the excitation intensity is improved, but the detector deterioration accelerates due to intense UV light
Solution Approach 1:
The current waveform is modulated periodically with the first modulated portion providing high current peaks for intense excitation, followed by the second modulated portion with low current that reduces UV light intensity. This periodic variation maintains necessary excitation intensity while allowing detector recovery periods, reducing cumulative detector deterioration
Solution Approach 2:
The high current peaks in the first modulated portion perform the excitation function preliminarily, creating the necessary atomic excitation before the low current second modulated portion takes over for sustained detection, thereby protecting the detector from continuous intense UV exposure
3Device complexity
If conventional analogue spark generator is used with unmodulated current waveform, then the device complexity is reduced, but the measurement precision deteriorates due to poor control over current profile
Solution Approach 1:
The spark generator transitions from static unmodulated current to dynamic modulated current waveform. The modulation allows real-time variation of current amplitude and timing, enabling precise control over the spark characteristics while maintaining reasonable device complexity through efficient modulation circuitry
Solution Approach 2:
The current waveform parameters (amplitude, duration, inter-peak intervals) are changed through modulation to optimize both trace element and alloying element analysis. This parameter control achieves high measurement precision without requiring overly complex device architecture
4Measurement precision
If high current peaks of variable amplitude are used for trace element analysis, then the detection sensitivity is improved, but the device complexity increases due to modulation requirements
Solution Approach 1:
The modulation creates periodic high current peaks with variable amplitude patterns optimized for trace element detection. This periodic structure allows sensitive detection while using relatively simple modulation circuitry, balancing detection sensitivity with 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
This approach enhances the precision of elemental analysis by controlling high and low energy transitions, reducing detector deterioration, and improving the separation of spectral background from useful transitions, enabling more accurate determination of both trace and alloying elements.
Implementation Method 1
a spark (herein used to refer to any electrical spark, arc or discharge) is used to rapidly vaporise a sample and excite elements in the vapourised sample
Implementation Method 2
Light is emitted by the excited elements of the sample as transitions occur from an excited state to a lower energy state
Implementation Method 3
an optical system for dispersing the emitted light into discrete wavelengths
Data Source
AI summary
The invention provides a spark generator for generating a spark for optical emission spectroscopy (OES), wherein the spark has a current waveform comprising a first modulated portion which comprises a plurality of relatively high current and high gradient peaks of variable amplitude and/or inter-peak duration and a second modulated portion of relatively low current and low gradient which is substantially without modulated peaks. The spark is preferably generated from two or more programmable current sources. The invention also provides an optical emission spectrometer comprising the spark generator and a method of optical emission spectroscopy using the spark generator.