Figure 5.

Calculation of linear attenuation coefficient of water and plexiglass. Comparison between the mass attenuation coefficient (red line) and the mass energy-absorption coefficient (black line) for plexiglass (dotted line) and water (solid line) as a function of the photon energy; μ/ρ = mass attenuation coefficient (for plexiglass or water), μ_en/ρ = mass energy-absorption coefficient (for plexiglass or water); the data used for the construction of the graph are available online at http://www.nist.gov/pml/data/xraycoef/index.cfm.