Optimization of FLUKA detector model for HPGe array

Abstract

Monte Carlo codes, such as FLUKA, are widely used to optimize calibration of spectrometric systems. HPGe detector array (HDA) for lung monitoring was modeled in FLUKA code using available information about their geometry and optimized for efficiency using 241Am point source at smaller distances (<10 cm) as in case of in-vivo monitoring scenarios. Thickness of dead layer (DL) on the top and lateral detector surfaces for low energy counting was determined by considering the experimental and simulated efficiency for various energies. Using trial and error method, optimized DL thickness was found out to be 2.5 μm on top surface and 1.8 mm on lateral surfaces for each HPGe detector in the array. For the optimized model, it was found that the simulated and experimental efficiency and the simulated and experimental spectra were in reasonable agreement. Optimization of the HDA was an important benchmarking step to reduce the simulation errors before they are implemented in complex numerical problems using computational phantoms.

Keywords

• dead layer
• fluka
• gamma spectrometry
• hpge detector array