Ratio of germanium detector peak efficiencies at photon energies of 4.4 and 11.7 MeV: Experiment versus simulation

Spencer Carson, Christian Iliadis, John Cesaratto, Art Champagne, Lori Downen, Marija Ivanovic, John Kelley, Richard Longland, Joseph R. Newton, Gencho Rusev, Anton P. Tonchev

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

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 = 4212 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 11 B(p, γ)12C 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 26cm) 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%. Another 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.

Original languageEnglish (US)
Pages (from-to)190-198
Number of pages9
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume618
Issue number1-3
DOIs
StatePublished - Jun 1 2010

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Germanium
germanium
Photons
Detectors
detectors
photons
simulation
Experiments
energy
rays
Astrophysics
nuclear astrophysics
Tomography
resonance fluorescence
Fusion reactions
angular correlation
Fluorescence
Crystals
tomography
computerized simulation

Keywords

  • Computed tomography
  • Full-energy peak efficiencies
  • Gamma-ray spectrometry
  • HPGe detector
  • High γ - Ray energy
  • Monte Carlo simulations
  • Radiography

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation

Cite this

Ratio of germanium detector peak efficiencies at photon energies of 4.4 and 11.7 MeV : Experiment versus simulation. / Carson, Spencer; Iliadis, Christian; Cesaratto, John; Champagne, Art; Downen, Lori; Ivanovic, Marija; Kelley, John; Longland, Richard; Newton, Joseph R.; Rusev, Gencho; Tonchev, Anton P.

In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 618, No. 1-3, 01.06.2010, p. 190-198.

Research output: Contribution to journalArticle

Carson, Spencer ; Iliadis, Christian ; Cesaratto, John ; Champagne, Art ; Downen, Lori ; Ivanovic, Marija ; Kelley, John ; Longland, Richard ; Newton, Joseph R. ; Rusev, Gencho ; Tonchev, Anton P. / Ratio of germanium detector peak efficiencies at photon energies of 4.4 and 11.7 MeV : Experiment versus simulation. In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2010 ; Vol. 618, No. 1-3. pp. 190-198.
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AU - Carson, Spencer

AU - Iliadis, Christian

AU - Cesaratto, John

AU - Champagne, Art

AU - Downen, Lori

AU - Ivanovic, Marija

AU - Kelley, John

AU - Longland, Richard

AU - Newton, Joseph R.

AU - Rusev, Gencho

AU - Tonchev, Anton P.

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N2 - 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 = 4212 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 11 B(p, γ)12C 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 26cm) 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%. Another 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.

AB - 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 = 4212 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 11 B(p, γ)12C 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 26cm) 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%. Another 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.

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