Soft X-ray photon energy calibration using multilayer mirror

A synchrotron beamline requires a set of reference values for calibration of photon beam energy, which are generally obtained from the absorption edges of different materials. However, due to oxidation and other chemical effects, these values are often different from the values of a pristine material. This makes the task of energy calibration difficult. In the present study, we have used a W/B4C multilayer for wavelength calibration for Soft x-ray reflectivity beamline (BL-03) at Indus-2. The structural parameters of the multilayer were obtained from Grazing Incidence X-ray Reflectivity (GIXRR) measurements. For energy calibration of soft x-ray beam, the reflectivity data at three different wavelengths were collected and analyzed to find correct wavelength values. The values so obtained were linearly interpolated to generate a curve for photon beam energy for 400-1500eV energy range.