Neutron transmission of single-crystal sapphire

Thermal and cold neutron transmission time-of-flight measurements have been taken on blocks of single-crystal sapphire. The transmission characteristics of single-crystal sapphire are not altered by irradiation for a number of years within a beam port at a reactor. Cooling the filter is only useful for the production of beams with the longest wavelengths. Even for poorer grade sapphire there is no degradation of the neutron transmission characteristics. (orig.)