Element-Sensitive Computed Tomography with Fast Neutrons

We demonstrate that energy-sensitive neutron transmission measurements can be used in conjunction with computed tomography to determine spatial distributions of specific elements in a sample containing elements of biological interest. A neutron continuum with energies up to 8.6 MeV is produced by 9Be(d, n)10B reactions in a thick target. The neutrons are collimated to a narrow beam and are used in a translate-rotate scan of the sample. Pulsed beam time-of-flight techniques are used to measure neutron transmission through the sample. Structure in the energy dependence of the transmission is used to determine the amounts of various attenuating elements encountered by the beam. These quantities are used in tomographic reconstructions of the sample.