  Resistivity Rho(T), Hall coefficient RH(T), superconducting transition
temperature Tc and slopes of the upper critical field dHc2/dT were studied in
(Ba1-xKx)Fe2As2 (x = 0.218, 0.356, 0.531) single crystals irradiated with fast
neutrons. It is found that dTc/dRhoSC - the rate of decreasing Tc as a function
of the RhoSC (RHoSC is the resistivity at T = Tc) - linearly increases with
concentration x. Slow changes in the Hall coefficient RH, as well as the
quadratic electronic contribution to the resistivity, show that there are no
substantial changes in the topology of the Fermi surface caused by irradiation.
The slopes of the upper critical field dHc2/dT in ab- and c-directions as a
function of RHoSC determined by Hall measurements show a reasonable agreement
with a model that suggests constancy of the band parameters.
