Plasma Emission Impurity Measurement With Interference Trapping
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Solution Overview
Problem
Current plasma emission systems for measuring impurities like nitrogen in rare and noble gases face interference issues from other impurities, leading to inaccurate measurements, especially at sub-ppb and high ppm levels, and lack long-term stability due to non-linearity and environmental factors.
Innovation Solution
A method and system that utilize a series of trapping means to remove interfering impurities, add moisture to stabilize the gas sample, and use a plasma emission system with emission wavelength correction and background subtraction to provide accurate measurements, ensuring linearity and stability across a wide concentration range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If plasma emission detection is used to measure inert impurities like N2 in noble gases, then the measurement capability is enabled, but interference from other impurities and non-linearity problems occur
Solution Approach 1:
The patent extracts and removes interfering impurities from the gas sample before measurement using selective trapping mechanisms. Different impurities are trapped by specific means (e.g., molecular sieves for water, catalysts for hydrocarbons) to isolate the target impurity for accurate measurement.
Solution Approach 2:
The patent modifies plasma parameters such as power input, frequency, and gas flow rates to optimize the emission signal for the target impurity while minimizing interference from other components. Parameter adjustment is used to linearize the response and improve measurement accuracy.
2Adaptability or versatility
If multiple impurities are present in the gas sample, then real-world applicability is improved, but interference and non-linearity increase
Solution Approach 1:
The patent segments the impurity removal process into multiple stages using different trapping mechanisms for different impurity types. This sequential approach allows each impurity to be addressed separately, maintaining measurement reliability even when multiple impurities are present simultaneously.
Solution Approach 2:
The patent introduces intermediary substances or conditions (such as controlled moisture addition) that mediate between the complex mixture of impurities and the measurement system. These intermediaries stabilize the plasma emission characteristics and reduce non-linearity effects.
3Adaptability or versatility
If the measurement range is extended from sub-ppb to 10,000 ppm, then the versatility is improved, but non-linearity and interference effects worsen
Solution Approach 1:
The patent employs dynamic adjustment of plasma power and other parameters based on the detected impurity concentration level. The system automatically optimizes operating conditions for each measurement range, maintaining linearity and accuracy from sub-ppb up to 10,000 ppm.
Solution Approach 2:
The patent implements feedback mechanisms that monitor the emission signal characteristics and adjust plasma parameters in real-time. This feedback control compensates for non-linearity and interference effects across the entire concentration range, ensuring consistent measurement precision.
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 solution achieves highly accurate, reliable, and stable measurements of nitrogen in noble gases, eliminating interference and non-linearity issues, enabling precise detection from sub-ppb to 10,000 ppm levels with long-term stability.
Implementation Method 1
The basic concept of this system is to get a discharge through the gas to create plasma, i.e. a gaseous ionized zone. The molecules of the background gas get excited and excite the gas molecules of N2 impurities which in turn emit various spectral emission wavelengths characteristic of N2.
Implementation Method 2
This method is generally known as plasma emission detection and is used with sample background gases that are easy to ionize with the help of electrical or electro magnetic field generator. The molecular species in the vapour phase is excited to emit light, then, the spectrum and the intensity of the emitted light are analyzed to determine the concentration of impurity in the sample.
Implementation Method 3
A method and system that uses a combination of trapping means to remove interfering impurities
Implementation Method 4
adding moisture to the gas sample at the outlet of the impurities trap
Data Source
AI summary
The invention provides a system and a method of eliminating interference for impurities measurement in noble gases based on emission spectroscopy which provide very stable, sensitive and interference free results. The method mainly relies on the use of a combination of particularly designed means serially connected for cancelling interferences and proper means for correcting linearity issues. The proposed method is particularly advantageous since it offers long-term stability while providing very accurate and reliable results, even at sub-ppb and up to 10,000 ppm levels, whatever the surrounding conditions and the additional impurities that could be present in the gas under analysis.