Abstract In the frame of the PANDORA_Gr3 project, aiming at measuring for the first time in-plasma nuclear β -decays of astrophysical interest, an innovative multi-diagnostic approach to correlate plasma parameters to nuclear activity has been proposed 1–3. This is based on several detectors and techniques (optical emission spectroscopy, RF systems, interferopolarimetry) and here we focus on high resolution spatially-resolved X-ray spectroscopy, performed by means of a X-ray pin-hole camera setup sensitive in the 0.5–20 keV energy domain. We present measurements on an Ar plasma heated by Electron Cyclotron Resonance at the ECR-plasma lab of ATOMKI-Debrecen. The achieved spatial and energy resolution were 0.5 mm and 300 eV at 8 keV, respectively 4. The new algorithm of analysis for single-photon-counted images has been developed allowing an investigation in High-Dynamic-Range (HDR) mode. Hence a spatially resolved quantitative characterization of plasma vs. plasma walls emitted spectra was done; the investigated electrons are the ones crucial for in-plasma ionization. Both stable and turbulent plasma regimes can be investigated.