Determination of the multiple scattered fraction as a function of target thickness

In the present work, the multiple scattered fraction (MSF) was investigated experimentally for HgO and PbO targets of various thicknesses. The targets were excited by 59.54 keV gamma rays emitted from a 5 Ci Am-241 annular radioactive source and the emitted photons were collected using a high-resolution HPGe semiconductor detector with a resolution of 182 eV at 5.9 keV placed at a scattering angle of 168 degrees. Our results show that the number of multiple scattered photons exponentially increases with the increase of target thickness for scattering (Compton and coherent) and characteristic (K alpha(2) and K alpha(1)) peaks and then saturates at a particular value of the target thickness called saturation thickness.