Determination of electron temperature in an ion source

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SUMMARY

The discussion focuses on determining the electron temperature in an ion source utilizing Electron Cyclotron Resonance (ECR). The Saha equation is proposed for this purpose, specifically the formula ##\frac{n_en_i}{n_a}=\frac{g_eg_i}{g_a}*3*10^{21} T^{3/2} e^{-J/T}##. The McWhirter criterion is referenced to assess the applicability of the Saha equation, defined as ##n_e >>1.6*10^{12}T^{1/2}*\Delta E^3##, where ##n_e## is electron density, T is electron temperature in eV, and ##\Delta E## represents the energy gap between states. The user seeks clarification on the appropriate value of ##\Delta E## for singly charged helium.

PREREQUISITES
  • Understanding of the Saha equation in plasma physics
  • Familiarity with the McWhirter criterion for electron density
  • Knowledge of energy levels in atomic physics, particularly for helium
  • Basic principles of Electron Cyclotron Resonance (ECR) ion sources
NEXT STEPS
  • Research the specific energy levels and transitions for singly charged helium
  • Study the application of the Saha equation in plasma diagnostics
  • Explore the McWhirter criterion in detail for various ion sources
  • Investigate methods for measuring electron density in ECR ion sources
USEFUL FOR

Researchers in plasma physics, engineers working with ion sources, and physicists studying electron temperature measurements in ECR systems.

HeavyIon
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How to correctly determine the temperature of electrons in an ion source based on ECR?
Is it possible to use the Saha equation?
##\frac{n_en_i}{n_a}=\frac{g_eg_i}{g_a}*3*10^{21} T^{3/2} e^{-J/T}##
Using the search, I found the McWhirter criterion for the applicability of the formula above:
##n_e >>1.6*10^{12}T^{1/2}*\Delta E^3##
Here ##n_e## is the electron density in ##cm^{-3}##, T is the electron temperature in ##eV##, and ##\Delta E## is the largest energy gap between upper and lower energy states that corresponds to one of the spectral lines used. I don't quite understand what \Delta E value should be considered in my case? I'm getting singly charged helium.
 

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