Abbas, M.I. (2001) A Direct Mathematical Method to Calculate the Efficiencies of a Parallelepiped Detector for an Arbitrarily Positioned Point Source. Radiation Physics and Chemistry, 60, 3-9.
http://dx.doi.org/10.1016/S0969-806X(00)00329-7

has been cited by the following article:

• TITLE: Direct Analytical Method to Calculate Photopeak Efficiency and Photopeak Attenuation Coefficient of NaI(Tl) Well-Type Detector

  AUTHORS: K. S. Al-Mugren, Mahmoud I. Abbas, Eman M. El-Bayoumi, N. S. Aly

  KEYWORDS: NaI(Tl) Well-Type Scintillation Detector, Full-Energy Peak Efficiency, Photopeak Attenuation Coefficient, Gamma-Ray Point Sources

  JOURNAL NAME: World Journal of Nuclear Science and Technology, Vol.6 No.2, April 28, 2016

  ABSTRACT: In this paper full-energy peak (photopeak) efficiency and photopeak attenuation coefficient of 3'' × 3'' NaI(Tl) well-type scintillation detector were calculated using gamma-rayisotropic radiating point sources (with photon energy: 0.245, 0.344, 0.662, 0.779, 0.964, 1.1732, 1.333 and 1.408 MeV) placed outside the detector well. These energies were obtained from 152Eu, 137Cs and 60Co. The relations between the full energy peak efficiency and photopeak attenuation coefficients, were plotted vs. photon energy at different sources to detector distance, and it found that the full energy peak efficiency decreased by increasing the distance between the source and the detector.