Figure 2: Response of Cherenkov detectors to various materials of the same aerial density.
From: Uncovering Special Nuclear Materials by Low-energy Nuclear Reaction Imaging
(a) Energy-dependent transmission measurement of several objects composed of different materials (a complete set of objects measured is provided in Supplementary Materials). The shaded regions of the spectrum are attributed to the Cherenkov detector response to 4.438 MeV and 15.1 MeV gamma rays produced in the 11B(d,n)12C reaction. (b) The two characteristic energy regions in (a) are used to reconstruct the effective atomic number of eight test objects composed of different materials. The known photon interaction cross sections for 4.438 MeV and 15.1 MeV gamma rays are used for a comparison calculation and shown as red line. The reconstruction method for the measured Cherenkov radiation spectrum and the comparison transmission calculation are described in detail in the Supplementary Materials. Error bars calculated for the measured ratios are smaller than the plot markers (circles) and are therefore not shown.
