Nuclear Instruments and Methods in Physics Research A

abstract The idea of measurements of groove density distributions of diffraction gratings suggested and firstrealized in Proceedings of SPIE 5858, (2005) 58580A consists of determination of the spatial frequencyof the first harmonic peak appearing in the power spectral density (PSD) distribution of the gratingsurface profile observed with a microscope. Using a MicroMap TM -570 interferometric microscope, it wasexperimentally proven that this technique is capable of high precision measurements with x-raygratings with groove densities of about 250 grooves/mm, varying along the grating by 75%. In thepresent work, we provide analytical and experimental background for useful application of PSDcharacterization of groove densities of diffraction gratings. In particular, we analyze the shape ofharmonic peaks and derive an analytical fitting function suitable for fitting the PSD peaks obtained withgratings with a variety of groove shapes. We demonstrate the capabilities of the method by applicationto the groove density distribution measurements with a 300-groove/mm grating suitable for soft x-rayapplications.& 2012 Elsevier B.V. All rights reserved.