A quick technique to improve the geometry characterisation of aged HPGe detectors for MC code efficiency calculation

Area of Science:

• Nuclear instrumentation
• Computational physics
• Metrology

Background:

• Accurate efficiency calibration is crucial for High-Purity Germanium (HPGe) detectors in radioactivity measurements.
• Initial Monte Carlo (MC) simulations using nominal detector parameters showed significant deviations from established activity values.
• The EMRP JRP MetroMETAL project highlighted the need for improved detector modeling for reliable efficiency calculations.

Purpose of the Study:

• To optimize a virtual HPGe detector model for accurate Monte Carlo efficiency calculations.
• To investigate the impact of detector parameter adjustments on simulation accuracy.
• To compare the performance of LABSOCS® and PENELOPE 2011 for efficiency calculations with different source geometries.

Main Methods:

• Creation of a virtual HPGe detector model based on an aged detector image.
• Optimization of the virtual detector's construction parameters to minimize simulation deviations.
• Calculation of detector efficiencies for point and voluminous sources using LABSOCS® and PENELOPE 2011 MC codes.

Main Results:

• The optimized virtual detector model significantly reduced deviations from assured activity values compared to the nominal model.
• LABSOCS® and PENELOPE 2011 provided comparable efficiency values for point sources.
• Differences in efficiency calculations were observed for voluminous sources between the two simulation codes, highlighting the importance of source geometry in MC simulations.

Conclusions:

• Virtual detector optimization is essential for achieving accurate MC efficiency calculations, especially with limited resources.
• The choice of MC simulation code and accurate modeling of source geometry are critical for reliable radioactivity measurements.
• This work contributes to the metrology of radioactivity by improving the accuracy of HPGe detector efficiency determination.