This article discusses the effect of different potential spectra of neutrons leaking from an inertial confinement fusion (ICF) pellet on integral parameters characterizing the blanket performance. We have compared time dependent and steady state neutron calculations to determine the neutron and gamma spectra from the target. Results show, that assuming a fuel burnup-average ρR parameter,<ρR>b, in the steady state method, realistic spectra can be obtained. The influence of the fuel <ρR>b, ρΔR pusher parameter as well as that of the gammas exploding from the target, on the chamber response has been analyzed.