Development of a forward model for a new multi-energy soft x-ray diagnostic on MST

The multi-energy soft x-ray (ME-SXR) diagnostic installed on MST utilizes a novel calibration of the DECTRIS PILATUS3 100k x-ray detector to achieve a combination of spatial and spectral sensitivity. Forward modeling is required to extract valuable information on underlying plasma parameters (T_e, n_e, etc.) from data collected by the diagnostic. A full forward model is under development which calculates emission from the given plasma profiles using information from the Atomic Data and Analysis Structure (ADAS) code. ADAS calculates ionization state fractions for impurity ions, including the effects of charge-exchange with neutral particles. ADAS is also used to calculate x-ray emissivity due to free-free, free-bound, and bound-bound electron-ion interactions. The model also incorporates the response of the detector based on calibration results, including effects from charge-sharing between neighboring pixels. A method for using this model to infer plasma properties using Bayesian probability theory is presented. This model will be added to an existing integrated data analysis framework to make use of all available information. Work supported by the US DOE.