A novel method for the efficiency calibration of in situ gamma spectrometry systems.

The FEPE calibration of in situ gamma spectrometer is very complex and limits its widespread use. In this study, a novel method for the absolute FEPE calibration of in situ spectrometer is proposed. The proposed method is applied for the FEPE calibration of HPGe detector (GC-3020) intended to use for in situ measurements. The intrinsic FEPE of detector is determined by measuring standard radioactive point sources 152Eu,137Cs, 133Ba and 60Co at a distance of 25 cm from front face of the detector. The method is validated by Monte Carlo simulations in Geant4. The absolute FEPE values obtained through the proposed methodology are compared to those computed using MC simulations. A good agreement between them validates the proposed method, in the energy range of interest. The proposed method may be employed for the rapid calibration of in situ gamma spectrometry systems during nuclear emergency. • A method to calibrate in situ gamma spectrometer rapidly. • Intrinsic FEPE of detector measured using few point sources. • Radial extent of disk source is optimized for various detector sizes. • Method validated by computing FEPE using Geant4 MC simulation. [ABSTRACT FROM AUTHOR]