Determination of effective atomic number and electron density of heavy metal oxide glasses

ABSTRACT

The effective atomic number (Z_eff) and effective electron density (N_eff) of eight heavy metal oxide (HMO) glasses have been determined using the Monte Carlo simulation code MCNP for the energy range of 10 keV–10 MeV. The interpolation method was employed to extract Z_eff and N_eff values from the simulation and that calculated with the help of XCOM program. Comparisons are also made with predictions from the Auto-Z_eff software in the same energy region. Wherever possible, the simulated values of Z_eff and N_eff are compared with experimental data. In general, a very good agreement was noticed. It was found that the Z_eff and N_eff vary with photon energy and do not have extended intermediate regions where Compton scattering is truly dominating; only dips slightly above ∼1.5 MeV were recorded. Z_eff and N_eff are found to increase with PbO and Bi₂O₃ contents. It was found that the Z_eff value rather than the N_eff value is a better indicator for PbO and/or Bi₂O₃ contents.

KEYWORDS:

• MCNP
• effective atomic number
• glass
• effective electron number
• XCOM
• Auto-Z_eff program

Acknowledgements

The authors would like to thank cyclotron project, Exp. Nuclear Physics department, Nuclear Research Centre, Atomic Energy Authority, especially Dr. Ahmed M. M. Solieman, for using MCNP-4B code.