Calculate the linear attenuation coefficient for 0.5 MeV and 6.0 MeV gamma rays in concrete (r = 2.3 g/cm³) having an elemental composition by weight of hydrogen, 1.0%; oxygen, 52.9%; silicon, 33.7%; aluminum, 3.4%; iron, 1.4%; calcium, 4.4%; sodium, 1.9%; and potassium, 1.3%. Perform the complete calculation using mass attenuation coefficients taken from the NIST homepage. (http://physics.nist.gov/PhysRefData/XrayMassCoef/tab3.html)