The Army Pulse Radiation Facility Reactor is a fast pulse, or burst, reactor generally used to provide a fast neutron environment In response to several test requirements, a number of fast neutron-to-gamma converter shields have been designed, calibrated, and placed into operation to produce a pulsed or steady-state gamma environment of ionizing radiation. The four basic converter configurations are (a) a narrow pulse converter box which has produced a maximum gamma dose rate of 3.8 × 108 rad/sec with a pulse width at half-maximum power of 50 μsec; (b) a wide pulse converter box which has produced 6.7 × 107 rad/sec at 400 μsec; (c) a narrow pulse converter cavity that has produced 7.7 × 108 rad/sec at 50 μsec; and (d) a wide pulse converter cavity that has produced 7.7 × 107 rad/sec at 1 msec. In terms of rads tissue, the gamma-to-neutron dose ratio varies from 0.1 (no converter) to ∼5; while in terms of rads (silicon), the neutron dose is almost 2 orders of magnitude less than the gamma dose.