[Ifeffit] Strange low-r peak in Pt foil EXAFS

Dear All, My target is the L3-edge of Pt foil and Pt-contained high-entropy alloy. In the Pt foil L-edge FT-EXAFS (k range: 3-20 A-1), there is a strange peak lower than the first near neighboring peak. This low-r peak makes confused because I did not found in other metal foil spectra. Also this peak cannot be reduced by increasing the Rbkg value. When I decrease the k range, this strange peak disappears with phase shift. In the Pt-contained high-entropy alloy, this strange peak becomes more pronounced than the 1st NN. Can anyone can give me help interpret this strange peak? Best regards, Fan ******************* JASRI, Sping8 *******************