(a) Scattering profile of the empty glass capillary (blue). The calculated incoherent scattering fraction at sinθ/λ = 0.7 is 76% for glass and 69% for Si. The corresponding incoherent intensities are shown in red (glass, full line; Si, broken line; neglecting absorption). The green line shows the total background level consisting of the sum of the glass capillary and the incoherent scattering from Si, multiplied by the transmission of 0.643 owing to the absorption from the Si powder. (b) The scattering profile of Si is shown in red and the background as determined from (a). The green semi-transparent box indicates the region seen by the photon detector mounted at 2θ = 90°.