  On the base of more general model we assessed accuracy of method that is
widely used for post- tuning accelerator sections. Our consideration has shown
that for wide range of disk loaded waveguide (DLW) parameters using simple
tuning coefficients gives appropriate characteristics of DLWs. For injector
sections, in which phase velocity and amplitude change, there are some
deviation from the desired characteristics. It is necessary to evaluate the
influence of additional phase shift on beam characteristics at the injector
exit.
