Hi Ke, It sounds like you are putting a lot of UO2 in the beam, and I might be worried about self-absorption in fluorescence data. I’m not sure about transmission, if you have lots of absorption (edge step of >>1) then you’ll be doing EXAFS on pinholes and thin spots. What are you getting for transmission edge steps on that sort of sample? “Good” UO2 data for me can have an edge-step in transmission of 0.10 or less. In my personal experience as little as ~2 mg U /square cm in UO2 will result in good data. YMMV based on beamline. Best, Drew Latta From: ifeffit-bounces@millenia.cars.aps.anl.gov [mailto:ifeffit-bounces@millenia.cars.aps.anl.gov] On Behalf Of Ke Yuan Sent: Wednesday, October 15, 2014 10:20 AM To: bravel@bnl.gov; ifeffit@millenia.cars.aps.anl.gov Subject: [Ifeffit] Ke Hi Bruce, Thanks for your comments! I studied Shelly's paper and found my data does looks different, especially the first peak at 1.9 A, seems it splits into two in my case. I prepared this sample by pressing UO2 powder into a hole (2mm deep), which might have significant self-absorption effect, because it's not dilute and thin. Do you think this will change the peak amplitude? Best, Ke