Comunicazione
Space-resolved electron density and temperature evaluation in ECR ion sources plasma by X-ray pinhole camera spectroscopy.
Finocchiaro G., Naselli E., Mishra B., Biri S., Mazzaglia M., Pidatella A., Rácz R., Torrisi G., Mascali D.
X-ray space-resolved spectroscopy can be used to evaluate electron density and temperature distribution in magnetized plasmas. In the PANDORA project a high-resolution full-field X-ray pin-hole camera setup was developed, consisting of a 400 $\mu$m hole in a lead disk coupled to a 1MP X-ray CCD camera (1--20 keV energy range). Single-photon-counted (SPhC) and high-dynamical-range (HDR) analysis allowed 560 m and 230 eV @ 8.1 keV of spatial and energy resolution, respectively. Quantitative analysis has been performed on electron cyclotron resonance (ECR) argon plasmas, heated by 200 W microwave power at 14 GHz. Local electron density and temperature have been extracted by the analysis of both the local fluorescence and bremsstrahlung spectra, according to the theoretical emissivity model in the approximation of local Maxwell-Boltzmann electron energy distribution. The analysis method is a powerful tool to investigate the effects of magnetic confinement and the plasma heating dynamics, with relevant implications about R&D of ECR Ion Sources for accelerator physics, as well as for fundamental plasma physics and in-plasma nuclear physics research.