Analysis of neutron related background of the SXR GEM diagnostic on MAST-U

Soft X-Ray (SXR) diagnostics are crucial in magnetically confined nuclear fusion experiments for studying plasma behavior, such as magneto-hydrodynamic (MHD) instabilities and impurity dynamics. Gas Electron Multiplier (GEM) detectors offer a valuable approach for SXR detection, given their radiation hardness and unique combination of high-rate imaging and spectroscopic capabilities. This study investigates the impact of high neutron rate on the GEM detector spectroscopic response in the MAST-U spherical tokamak. A sample energy spectrum obtained from the GEM diagnostic is compared with Geant4 simulations of both SXR and neutron sources to characterize background effects and study the detector response.