scattering decrease with increasing the gamma ray energies. But
photoelectric absorption and coherent scattering interactions were
found to have a small effect on total mass attenuation coefficient in
this energy range. The incoherent (Compton) scattering interaction
was found to be the main interaction process in this energy range
for Inconel 738 superalloy.
The effective atomic numbers (Zeff) have been determined using
Eq. (6) and are given in Table 3. It is seen that the value of the effective
atomic numbers were decreased from 29.30 to 26.94 electron/
atom for theoretical and 29.31 to 26.43 electron/atom for experimental
with increasing of gamma ray energies. They are in good
agreement between experimental and theoretical values, as shown
in Fig. 3.
The number of electrons per unit mass, Ne, has been determined
from Eq. (7), and the result is shown in Table 3. It is seen that the
value of Ne were decreased from 3.108 to 2.858 1023 electron/g
for theory and 3.110 to 2.804 1023 electron/g for experimental
with increasing of gamma ray energies, as shown in Fig. 4.
6. Conclusions
The mass attenuation coefficients of Inconel 738 superalloy
were measured at the different energies of gamma ray using the
Compton scattering technique. There are corresponding of scattered
gammas ray energies between theoretical values and experimental
values, reflecting the validation of Compton scattering
system setup. The results show that mass attenuation coefficients,
effective atomic number and electron density decrease with the increase
in gamma ray energies. The result of partial interaction
show the same trend with mass attenuation values which incoherent
scattering is main interaction process for Inconel 738 superalloy
in 223–662 keV gamma ray energies.
Acknowledgements
The present work was partially supported by the National
Research Council of Thailand (NRCT). The authors would like to
thank Prof. L. Gerward for WinXCom software. J. Kaewkhao would
like to thank Thailand Center of Excellence in Physics (ThEP) for
partially funding support.