Temperature dependence of total neutron cross sections in thermal and keV regions

In the thermal neutron energy region, the inelastic scattering cross sections of Si have been measured at room temperature and at 6000C with a time-of-flight spectrometer using a single-crystal Si sample. The results are in good agreement with the calculated ones based on Debye model. A filtered neutron beam with an energy band of 23.3 to 25.3 keV has been used to measure the temperature dependence of the total cross section of Nb in the keV region. The cross section is averaged over the neutron energy band which covers a number of resonances. This average cross section shows the effect of Doppler broadening of the resonances. The sample thickness dependence of Nb has also been measured at 54 and 144 keV by using a Si-filtered beam