[en] A new approach was developed, employing the field-ion microscope technique, to determine directly radiation damage profiles in order-disorder alloys; the approach was applied to Pt₃Co. The experiment consisted of irradiating in situ, at 30⁰K, Pt₃Co specimens with low-energy (500 to 2500 eV) Ne⁺ ions. The specimens were subsequently dissected on an atom-by-atom basis employing the pulse field-evaporation technique. The latter procedure made it possible to determine the change in the Bragg-Williams long-range order parameter (S) as a function of distance from the irradiated surface. The measurement of ΔS/sub d/, where the subscript indicates damage, versus distance (x) constituted a radiation damage profile; the depth resolution of this profile was aproximately equal to 2 A. The mean depth of damage (anti x/sub d/) varied from approximately equal to 9 to 20 A and the standard deviation or straggling (Δx) varied from approximately equal to 6 to 18 A as the implantation energy was increased from 500 to 2500 eV. The radiation damage profiles have also been used to determine the effective stopping power of Ne in Pt₃Co