Gamma Spectroscopy of 129mXe Samples Produced at the MARIA Reactor for the Gamma-MRI Project

This report details the gamma spectroscopy analysis of a $^{129m}Xe$ sample produced through neutron activation of $^{128}Xe$ at the MARIA reactor. The energy, resolution, and efficiency calibrations of the gamma detector were performed, along with the identification and activity estimation of key radionuclides and external contaminants. Python scripts were developed for each required peak fitting and calibration curve. Special focus was given to the 196.5 keV gamma peak of $^{129m}Xe$, due to its importance for the Gamma-MRI project. The activity of $^{129m}Xe$ was estimated to be 77(4) M Bq at the end of irradiation, and with this, the cross-section of the $^{128}Xe$(n, γ)$^{129m}Xe$ reaction was estimated to be 0.31(6) b, consistent with available literature.