  Systematics of neutron scattering cross sections on various materials for
neutron energies up to several hundred MeV are important for ADSS applications.
Ramsauer model is well known and widely applied to understand systematics of
neutron nucleus total cross sections. In this work, we examined the role of
nuclear effective radius parameter (r$_0$) on Ramsauer model fits of neutron
total cross sections. We performed Ramsauer model global analysis of the
experimental neutron total cross sections reported by W. P. Abfalterer, F. B.
Bateman, {\it et. al.,}, from 20MeV to 550MeV for nuclei ranging from Be to U .
The global fit functions which can fit total cross section data over periodic
table are provided along with the required global set of parameters. The global
fits predict within $\pm 8%$ deviation to data, showing the scope for
improvement. It has been observed that a finer adjustment of r$_0$ parameter
alone can give very good Ramsauer model description of neutron total scattering
data within $\pm 4%$ deviation. The required r$_0$ values for Ramsauer model
fits are shown as a function of nuclear mass number and an empirical formula is
suggested for r$_0$ values as a function of mass number. In optical model
approach for neutron scattering, we have modified the real part of
Koning-Deleroche potentails to fit the neutron total cross sections using SCAT2
code. The modified potentails have a different energy dependence beyond 200MeV
of neutron energy and fit the total cross sections from Al to Pb.
