The generation rate of paramagnetic defects has been measured by means of Electron Paramagnetic Resonance over the 1015–1017‐10n  cm−2fluence range, using a low flux (7×101010n  cm−2 s−1) of fast neutrons; much higher yields are achievable than reported up to now. A comparison of 4.2‐  and 295‐K spectra evidences a narrowing of the hyperfine structure separation of the components of the AsGaquadruplet with increasing temperature.