Calibration of integrating sphere system designed for roughness correction in optical calibration of gauge blocks

A total integrated scattering (TIS) system consisting of an integrating sphere has been developed in KRISS for the purpose of measuring the effective roughness amplitude of gauge blocks and platens, which are necessary for the correction of phase shift due to roughness difference between gauge block and platen, in the calibration of gauge blocks by optical interferometry. Details on the TIS system and its calibration by using two different methods are described. The uncertainty of the effective roughness amplitude measurement by using the TIS system is evaluated to be 2 nm (k=1).