High precision X-ray measurements 2021

Probing Electron Properties in ECR Plasmas using X-ray Bremsstrahlung and Fluorescence Emission

9 Jun 2021, 12:40

20m

Contribution type Session

Speaker

Bharat Mishra (INFN - LNS)

Description

Emission spectroscopy has been long-employed as a powerful passive diagnostic tool to probe electron cyclotron resonance (ECR) plasma properties. By comparing experimentally measured spectra with suitable theoretical models, quantities of physical importance like particle density, temperature and charge state distribution can be estimated.Traditionally, optical emission spectroscopy has been used to probe cold electron properties ($T_e<10\mathrm{eV}$) [1] while X-ray bremsstrahlung spectroscopy has proved more useful for hot electrons ($T_e>50\mathrm{keV}$) [2].

Recently, phenomenological X-ray spectroscopic analyses have also been extended to include atomic line spectra, in order to deduce information about warm electrons ($T_e\sim 2-30\mathrm{keV}$) and ion densities [3,4], and inner-shell ionisation rates [5]. Here we present a new numerical method capable of describing simultaneously the bremsstrahlung background as well as volumetric K-line emission spectra of plasma ions, in the range $2-20\mathrm{keV}$ [6], thus allowing deduction of charge particle density and electron energy distribution function (EEDF). The technique can be also used to experimentally benchmark theoretically derived anisotropic EEDFs known to exist in ECR plasmas. This will prove useful for modelling space-resolved volumetric X-ray emissions [7] as well as for validating data inputs crucial for the PANDORA project.

REFERENCES
[1] O. Tuske et al, Rev. Sci. Instrum. 75, 1529 (2004)
[2] C. Baruè, M. Lamoureux, P. Briand, A. Girard and G. Melin, J. Appl. Phys. 76, 5 (1994).
[3] G. Douysset, H. Khodja, A. Girard and J.P. Briand, Phys. Rev. E. 61, 3 (2000).
[4] J.P. Santos, A. M. Costa, J.P Marques, M.C. Martins, P. Indelicato and F. Parente, Phys. Rev. A. 82, 062516 (2010).
[5] M. Sakildien, R. Kronholm, O. Tarvainen, T. Kalvas, P. Jones, R. Thomae and H. Koivisto, Nuclear Inst. and Methods in Physics Research A, 900 (2018).
[6] D. Mascali, G. Castro, S. Biri, R. Racz, J. Palinkas, C. Caliri, L. Celona, L. Neri, F.P. Romano, G. Torrisi and S. Gammino, Rev. Sci. Instrum. 87, 02A510 (2016).
[7] R. Rácz, S. Biri, J. Pálinkás, D. Mascali, G. Castro, C. Caliri, F. P. Romano and S. Gammino, Rev. Sci. Instrum. 87, 02A741 (2016).

Presentation materials

HPXM Presentation.pdf