Title of article :
Ratio of germanium detector peak efficiencies at photon energies of 4.4 and 11.7 MeV: Experiment versus simulation
Carson، نويسنده , , Spencer and Iliadis، نويسنده , , Christian and Cesaratto، نويسنده , , John and Champagne، نويسنده , , Art and Downen، نويسنده , , Lori and Ivanovic، نويسنده , , Marija and Kelley، نويسنده , , John and Longland، نويسنده , , Richard and Newton، نويسنده , , Joseph R. and Rusev، نويسنده , , Gencho and Tonchev، نويسنده , , Anton P.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2010
Full-energy peak efficiencies of germanium detectors are frequently investigated at γ -ray energies below 4 MeV using calibrated radioactive sources, while very accurate peak efficiencies for higher photon energies are essentially non-existent. Peak efficiencies in the energy range of E γ = 4 – 12 MeV are crucial for a number of applications, including nuclear astrophysics measurements of fusion reactions and resonance fluorescence experiments. We report on a novel method, using the 163 keV resonance in the B 11 ( p , γ ) C 12 reaction, of measuring accurately the ratio of full-energy peak efficiencies at 4.44 and 11.66 MeV. We derive this ratio for three different detector-target distances (3, 12 and 26 cm) directly from measured peak intensities and demonstrate that corrections are small ( γ -ray branching ratios, angular correlations, coincidence summing). Our measured full-energy peak efficiency ratios have a precision of 1.4–1.6%.
r important goal of our study was to determine to what precision full-energy peak efficiencies at high γ -ray energies can be predicted using the simulation codes Geant3 and Geant4. We imaged our detector using computed tomography and radiographs in order to extract reliable detector crystal dimensions. Based on these results, extensive computer simulations are performed. We find that the simulation results agree with the measured peak efficiency ratios within an uncertainty of 1.6% for Geant4 and 2.6% for Geant3. Our results are useful for assigning uncertainties when peak efficiencies are extrapolated from low energy data to high energies based on simulations only.
HPGe detector , Gamma-ray spectrometry , Full-energy peak efficiencies , High ? -ray energy , Radiography , computed tomography , Monte Carlo simulations
Journal title :
Nuclear Instruments and Methods in Physics Research Section A