Per-pixel attenuation histograms for 14 MeV neutron
and 60Co gamma-ray (1.17 and 1.33 MeV) transmissions
were calculated for 940 cargo images collected over a
period of 3 weeks. A more detailed manual analysis was
made of 202 cargo images collected over a 4-day window
inside this period. This detailed analysis included
additional information on the ULD type and manifest
details (where available). The breakdown by ULD type
is shown in Fig. 1. Detailed descriptions and drawings
of the different ULD types are available from a number
of sources on the web (e.g., Air Freight Council of
NSW, 2007). The commonest observed ULDs are AKEs
with dimensions of 1530 (width) 2010 (length) 1630
(height) mm. The commonest observed pallets are the
PMCs and PAGs with dimensions of 2440(2240 for
PAG) 3180 1630 mm. Cargos are scanned through the
narrower (width) dimension. Overall, about 50% of cargo
was loaded into ULDs and 50% on pallets.
F