In-Situ Estimation of Gamma-ray Sources Depths Using Coded-aperture Imager

The in-situ methodology was developed for estimation gamma-ray source depth using gamma-ray imager. The equipment used in this research utilized the EPSILON-G gamma ray imager, which features a coded-aperture and is equipped with a GAGG(Ce) scintillator array for image reconstruction to locate gamma-ray source. For in-situ imaging, the minimum imaging count (MIC), which determines imaging with minimal count in the range of 59.54 to 1332 keV, was acquired using the MCNPX-PoliMi codes and measurements. Using the MIC, the minimum detectable activity (MDA) was calculated, which determines the lowest concentration of surface radioactivity that can be imaged. A depth estimation method was developed for in-situ detection of radioactive materials at specific depths on the surface during radiological emergency situations. The method was validated by comparing the calculated results using
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Cs with the actual location of the gamma-ray sources in the images.