Determination of the optimal cylindrical geometry heights for gamma-ray spectrometric analysis

• Optimal sample thickness for γ spectrometry was determined.
• Estimation and experimental study for sample thickness and count rate was done.
• Optimal thickness was found to be 10 cm for E > 100 keV regardless the type of HPGe.
• For N-type HPGe, thicknesses 3.5 cm for 46.5 keV and 5 cm for 59.5 keV were found.
• Very good agreement between estimation and experimental results were found.

The optimal heights (sample thickness) for samples of cylindrical geometry analyzed by gamma-spectrometry with HPGe detectors have been determined by studying the correlation between the sample thickness and the sample mass multiplied by the efficiency. For energies higher than 100 keV, the optimal thickness for a cylindrical sample with a diameter of 6.8 cm was determined to be 10 cm, regardless of the type of HPGe detector. A strong relationship was observed between the optimal sample thickness and the gamma energy line (when E < 100 keV) and the density of the sample for N-type HPGe (R.eff. 60%) detectors. For a sample density 2 g cm−3, the optimal thickness was determined to be 3.5 cm at 46.5 keV and 5 cm at 59.5 keV.