[en] The fast-neutron hodoscope monitors fuel motion within thick opaque capsules during experiments at the Transient Reactor Test (TREAT) Facility. Capsules containing LMFBR test fuel are positioned at the center of the reactor and subjected to destructive radiation transients which simulate fuel motion during accident conditions. Fission neutrons born in the test fuel are sampled at down to submillisecond intervals by a two-dimensional array of hundreds of fast-neutron detectors located behind slots in an ex-core collimator. The slots are aimed through a hole in the reactor core at elements of a rectangular grid at the center-core capsule. The hodoscope measures and stores a dynamic two-dimensional image of test-fuel fission rate. Shielding effects have been treated by renormalizing each hodoscope channel count rate by the total count rate for all hodoscope channels. This enforces global mass conservation but yields systematic local and regional inaccuracies among channels. A locally consistent computational approach to this shielding problem has been developed