Estimation of electron temperature in 14.45 GHz ECR ion source plasma by analysis of Bremsstrahlung spectra

Abstract

Electron Cyclotron Resonance Ion Sources (ECRIS) are known to produce intense X-rays of the order of 100’s of keV. Energy of electrons in the resonantly heated microwave plasma has been estimated by analyzing the Bremsstrahlung spectra obtained using a standard alkali halide (NaI [Ti]) crystal detector. Experiments were carried out on argon plasma discharge from high performance ECR ion source operating at 14.45 GHz. The dependency of X-ray emission with microwave power has been studied in the range 50-400 W. It is verified that maximum energy gained by electrons in ECR plasma follows a power law Emax ⍺ P³/⁸. X-rays of more than 800 keV energy can be generated at very low microwave power as 400 W. The influence of magnetic field and gas pressure in the production of X-rays has also been analyzed.