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7.4 Tagged Neutron Beam for Sea Container Inspection
shown on the left side. An unfolding algorithm allows decomposing the mea-
sured energy spectrum into the sum of energy spectra and each spectrum in
the sum corresponding to one element (C, N, O, Fe…) with a weight related to
its chemical proportion. e obtained sum spectrum is plotted (black lines) in
the previous gures to compare with the measured spectrum and thus verify
the quality of the t. e dierent energy spectra recorded in the same upper
position for drugs and sugar are compared in Figure 7.71 conrming again that
heroin and cocaine can be distinguished from sugar, but not mar ...