(Solved): The atomic cross sections for the materials in a gadolinium oxysulfide intensifying screen for 50 ...

The atomic cross sections for the materials in a gadolinium oxysulfide intensifying screen for $$50?\mathrm{keV}$$ photons are: a. What is the cross section per target molecule of $${\mathrm{GdO}}_2\mathrm{S}$$ ? b. How many target molecules per unit area are there in a thickness $$?\mathrm{dx}$$ of material? c. What is the probability that a photon interacts in traversing $$1.2\mathrm{kg}{\mathrm{m}}^{?2}$$ of $${\mathrm{GdO}}_2\mathrm{S}?$$