A radiation scattering measurement system, such as an x-ray diffraction system, uses a modified beamstop, or attenuator, to allow simultaneous detection of energy scattered from a sample and energy transmitted through the sample. Rather than entirely blocking the transmitted beam energy from reaching a detector of the system, the attenuator blocks only an outer portion of the transmitted beam, so that a shadow region is created on the detector surrounding the detector region upon which the transmitted beam is incident. This local region of minimum intensity defines a boundary on the detector between the transmitted beam energy and the energy scattered from the sample. The attenuator also reduces the per-unit-area intensity of the transmitted beam using a broadband filter element, so that the transmitted beam does not saturate the detector. A single detector frame is taken containing the beam energy and the scattered energy, and the minimum intensity boundary between the two is located. The measurements from the different detector regions are then used to determine the relative intensity between the transmitted beam and the scattered energy, and a transmission coefficient is calculated.