Transmission electron microscopy (TEM) was used to compare the microstructural defects produced in an Fe9Cr model alloy during exposure to neutrons, protons, or self-ions. Samples from the same model alloy were irradiated using fission-neutrons, 2MeV Fe+ ions or 1.2MeV protons at similar temperatures (~300°C) and similar doses (~2.0dpa). The neutron-irradiated alloy contained visible interstitial dislocation loops with b=〈111〉, and on average ~5nm in size. The density varied from 2±1x10 20 m -3 (in the matrix far from dislocations and boundaries) to 1.2±0.3x10 23 m -3 (close to helical dislocation lines). Chromium α'-phase precipitates were also identified at a density of 7.4±0.4x10 23 m -3 . Self-ion irradiation produced mostly homogeneously distributed dislocation loops (6-7nm on average), and with a greater fraction of 〈100〉 loops (~40%) than was seen in the neutron-irradiated alloy, and at a density of 6.8±0.8 x10 22 m -3 . In contrast to the loops produced by neutron irradiation, the self-ion irradiated Fe9Cr contained only vacancy-type loops. Chromium also remained in solution. Proton-irradiated Fe9Cr contained interstitial dislocation loops close to helical-dislocation segments, similar to the neutron-irradiated sample. Chromium α'-phases were also identified in the proton-irradiated sample at a density of 2.5±0.3x10 23 m -3 , and large voids (up to 7nm) were found at a density over 10 22 m -3 . Like the neutron-irradiated sample, the density of dislocation loops was also heterogeneously distributed; far from grain boundaries and dislocation lines the density was 2.5±0.4 x10 22 m -3 , while close to helical dislocation lines the density was 8.1±1.3 x10 22 m -3 .