Fiber Optic Gas Temperature Measurement in Plasma
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for measuring gas temperature in low-pressure RF plasmas are inadequate due to electromagnetic interference and limitations in traditional spectroscopic diagnostics, which result in inaccurate and unsatisfactory measurements.
Innovation Solution
A device comprising a fiber optic temperature sensor, quartz tube, circulator, spectrometer, and broadband light source, where the fiber optic temperature sensor uses an optical signal to measure the central wavelength of reflected light, avoiding electromagnetic interference and providing accurate, fast gas temperature measurements in plasmas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thermocouple sensor is used for gas temperature measurement, then the measurement method is simple and widely used, but the measurement is susceptible to electromagnetic fields and the thermocouple interferes with the plasma
Solution Approach 1:
The patent introduces an optical fiber as an intermediary medium to transmit light signals between the external light source/spectrometer and the plasma environment. This optical intermediary allows temperature measurement without direct electrical contact, eliminating electromagnetic interference while maintaining measurement capability through optical wavelength analysis of plasma emission
Solution Approach 2:
The patent replaces the electrical-based thermocouple measurement system with an optical-based measurement system. Instead of using electrical signals that are susceptible to electromagnetic interference, the system uses optical wavelengths to probe plasma temperature, substituting the mechanical/electrical measurement approach with an optical one that is immune to electromagnetic fields
2Reliability
If traditional spectroscopic diagnostics are used for gas temperature measurement, then the measurement can be performed in plasma environment, but the response time is long and the equipment is expensive with complicated calculation process
Solution Approach 1:
The patent extracts and utilizes only the most relevant spectral information - specifically the wavelength position of emission lines - while ignoring complex spectral analysis. By focusing solely on wavelength measurement rather than full spectral decomposition, the system achieves fast response times while maintaining accuracy in plasma environments
Solution Approach 2:
The patent applies partial action by performing only the necessary wavelength measurement without conducting complete spectral analysis. Instead of analyzing the entire spectrum with complex calculations, the system selectively measures only the wavelength positions of relevant emission lines, reducing computational complexity and response time while maintaining measurement reliability
3Measurement precision
If traditional spectroscopy diagnostic methods are used, then the measurement can be performed, but the spatial resolution is poor and the calculation process is complicated
Solution Approach 1:
The patent applies local quality by using a focused optical fiber probe that concentrates measurement at a specific spatial location within the plasma. The optical fiber delivers and collects light from a localized region, enabling spatially resolved temperature measurements with high spatial resolution while keeping the calculation process simple through direct wavelength-to-temperature conversion
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 device enables precise and rapid measurement of gas temperature in plasmas, effectively characterizing electromagnetic effects in low-pressure RF-CCP systems with improved spatial resolution and resistance to electromagnetic interference.
Implementation Method 1
the fiber optic temperature sensor uses an optical signal to measure the central wavelength of reflected light
Implementation Method 2
the fiber optic temperature sensor is connected to the circulator by means of an optical fiber
Implementation Method 3
a spectrometer, a broadband light source and a computer, where... the spectrometer is electrically connected to the computer which is configured to read and record spectra collected by the spectrometer
Data Source
AI summary
The present invention discloses a device for measuring gas temperature in plasma, including: a vacuum chamber, a fiber optic temperature sensor, a quartz tube, a circulator, a spectrometer, a broadband light source and a computer. One end of the quartz tube is inserted into the vacuum chamber. The fiber optic temperature sensor is located in the plasma in the vacuum chamber and fixed to the quartz tube. The fiber optic temperature sensor is connected to the circulator by means of an optical fiber passing through the quartz tube. The circulator is connected to the broadband light source and the spectrometer through optical fibers, respectively. The spectrometer is electrically connected to the computer which is configured to read and record spectra collected by the spectrometer.