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- Mahmoud I Abbas
- Applied radiation and isotopes : including data…
- 2001

Direct mathematical methods to calculate total and full-energy peak (photopeak) efficiencies, coincidence correction factors and the source self-absorption of a closed end coaxial HPGe detector for Marinelli beaker sources have been derived. The source self-absorption is determined by calculating the photon path length in the source volume. The attenuation… (More)

- Mahmoud I Abbas, Sherif S. Nafee, Younis S Selim
- Applied radiation and isotopes : including data…
- 2006

The calibration of cylindrical detectors using different types of radioactive sources is a matter of routine. The most accurate method, that of experiment, is limited by several factors when the energy interval is broad, requiring a relatively large number of primary standards, implying considerable investment of money and time. Several other techniques can… (More)

- Mahmoud I Abbas
- Applied radiation and isotopes : including data…
- 2006

Knowledge of the solid angle (and consequently, the geometrical efficiency) is essential in all absolute measurements of the strengths of radioactive materials and to calibrate detectors. The method of high-efficiency gamma counting by means of well-type HPGe and NaI (Tl) detectors is widely used and has proved a powerful tool, particularly when… (More)

- Mahmoud I Abbas
- Applied radiation and isotopes : including data…
- 2001

A straightforward analytical formulae for the computation of total and full-energy peak efficiencies of NaI (Tl) and HPGe well-type detectors are deduced. In addition, the attenuation of photons by the source container and the detector end cap materials is presented in a direct mathematical expression. Results are compared with previous treatments.

- Leticia S Pibida, Sherif S. Nafee, Michael P. Unterweger, Michelle Hammond, Lisa R . Karam, Mahmoud I Abbas
- Applied radiation and isotopes : including data…
- 2007

Measurements of radioactive noble gases are routinely made with gamma-ray spectrometers. This work describes the calibration of high purity germanium detectors provided by the full-energy-peak efficiency as a function of the gamma-ray energy. A comparison of measured efficiency values with a new, simplified method based on a direct mathematical method is… (More)

- Zhiliang Wu, Chih Min Liu, +4 authors Hongguang Xu
- The journal of physical chemistry. B
- 2005

Nickel oxide nanowires modified by poly(vinylpyrrolidone) (PVP) were synthesized via a simple chemical pattern. For the first time NiO nanowires with diameters ranging from 40 to 100 nm with the expected ratio (length vs diameter) ranging from 54 to 90 were grown using a simple solution-phase approach (mild method). These nickel nanowires exhibited unique… (More)

- Sherif S. Nafee, Mahmoud I Abbas
- Applied radiation and isotopes : including data…
- 2008

Radiation portal monitor (RPM) systems are widely used at international border crossings, where they are applied to the task of detecting nuclear devices, special nuclear material, and radiation dispersal device materials that could appear at borders. The requirements and constraints on RPM systems deployed at high-volume border crossings are significantly… (More)

- Mahmoud I Abbas
- Applied radiation and isotopes : including data…
- 2006

Direct analytical formulae for the efficiency calibration of gamma (scintillation and semiconductor) detectors using an arbitrarily positioned radiating point source are extended to include sources with volumetric shapes. The attenuation of photons by the source itself (self-absorption) is determined by calculating the photon path length through the source… (More)

- Ayman Hamzawy, Mohamed Salem Badawi, Abouzeid Ahmed Thabet, Mona M Gouda, Ahmed M El-khatib, Mahmoud I Abbas
- The Review of scientific instruments
- 2016

Gamma-ray detectors are widely used in many fields like environmental measurements, medicine, space science, and industry, where the detector geometrical, total, photopeak efficiencies and peak-to-total ratio could be required. The calculation of the detector efficiency depends mainly on the value of the geometrical efficiency, which depends on the solid… (More)

- Ayman Hamzawy, Dimitar N Grozdanov, +7 authors Mona M Gouda
- The Review of scientific instruments
- 2016

Scintillation crystals are usually used for detection of energetic photons at room temperature in high energy and nuclear physics research, non-destructive analysis of materials testing, safeguards, nuclear treaty verification, geological exploration, and medical imaging. Therefore, new designs and construction of radioactive beam facilities are coming… (More)

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