Figure 4.

Neutron transmission spectra for BaBrCl:Eu samples with different concentrations of Eu dopant, as shown in the legend (in mole %), calculated from equations (2) and (3) using tabulated cross sections from the ENDF database. A constant 5 mm sample thickness, a natural isotopic abundance for Eu (¹⁵¹Eu 47.8% and ¹⁵³Eu 52.2%) and a density of 4.5 Mg m⁻³ are assumed in the calculations. Strong neutron resonance absorptions at ∼0.42, 0.28, 0.22, 0.18 and 0.16 Å (∼0.46, 1.06, 1.76, 2.47 and 3.39 eV) are present for the Eu dopant and can be used for unambiguous imaging in energy-resolved experiments, as well as Ba and Br for high-energy resonances. In the thermal and cold neutron ranges, Eu provides nearly half of the attenuation contrast, even at the 0.5% dopant concentration.