The influence of fast neutron irradiation on the crystal structure, resistivity p(T) and Hall coefficient RH(T) in heavy fermion (HF) compound CeCu6 was investigated. Neutron powder diffraction shows that irradiation leads to increase in the unit cell volume by 0.3% and approximately 1.5 times increase in the Debye-Waller temperature factor with preservation of the Puma initial crystal structure. Nevertheless, such small changes result in practically full suppression of the HF state, i.e., at low temperature, the square-law term disappears and a logarithmic term corresponding to strong magnetic scattering (the Kondo effect) appears in rho(T) and R-H(T) dependences. Within the framework of the multi-band model, this points to a strong reduction in the HF charge carrier concentration, whereas changes in the band parameters of light charge carriers are small. (c) 2005 Elsevier B.V. All rights reserved.