The cross-section for photoelectric-equivalent interactions in germanium for gamma-ray spectral analysis

This research analyzes and quantifies the multiple interactions that lead to full-energy deposition in thick germanium detectors under various geometric conditions by Monte Carlo simulations and confirms the simulated efficiency results by measuring radioactivity standards. It examines the photoelectric-equivalent peak relative to the gamma-ray flux passing through the crystal, analyzes it in terms of the influence of detector dimensions, and summarizes the findings in simple expressions. It also gives a simple theoretical approach, based on the average characteristics of detector and gamma-ray interactions, to calculate the intrinsic detector efficiency.;It is found that Monte Carlo simulation can be used to generate the shape of the response over the entire energy range (40-2500 keV) for several geometries. These simulations match well with the experimental measurements of gamma-ray standards for different geometries. This provides a simpler way for users to generate efficiencies for various configurations of source and detector with Monte Carlo simulations and analytical functions, and defines a way to find the associated uncertainties. Based on Monte Carlo simulations, confirmed with three detector measurements, it provides multiple interaction absorption coefficients as function of energy and detector dimension for germanium detectors.