The first measurement of plasma density in an ECRIS-like device by means of a frequency-sweep microwave interferometer

D Mascali; G Torrisi; O Leonardi; G Sorbello; G Castro; L G Celona; R Miracoli; R Agnello; S Gammino

doi:10.1063/1.4963710

The first measurement of plasma density in an ECRIS-like device by means of a frequency-sweep microwave interferometer

Rev Sci Instrum. 2016 Sep;87(9):095109. doi: 10.1063/1.4963710.

Authors

D Mascali¹, G Torrisi¹, O Leonardi¹, G Sorbello¹, G Castro¹, L G Celona¹, R Miracoli², R Agnello¹, S Gammino¹

Affiliations

¹ INFN - Laboratori Nazionali del Sud, 95123 Catania, Italy.
² ESS Bilbao, 48170 Zamudio, Spain.

PMID: 27782559
DOI: 10.1063/1.4963710

Abstract

The note presents the first plasma density measurements collected by a novel microwave interferometer in a compact Electron Cyclotron Resonance Ion Sources (ECRIS). The developed K-band (18.5 ÷ 26.5 GHz) microwave interferometry, based on the Frequency-Modulated Continuous-Wave method, has been able to discriminate the plasma signal from the spurious components due to the reflections at the plasma chamber walls, when working in the extreme unfavorable condition λ_p ≃ L_p ≃ L_c (λ_p, L_p, and L_c being the probing signal wavelength, the plasma dimension and the plasma chamber length, respectively). The note describes the experimental procedure when probing a high density plasma (n_e > 1 ⋅ 10¹⁸ cm^-3) produced by an ECRIS prototype operating at 3.75 GHz.