Hi Jason, I didn't try to use the original data (and, like Bruce's rant, once I saw that it was a spec file with multiple scans [er file and with 100+ columns, I didn't even try). But from looking at the spectra Bruce posted, it's hard to see what the problem might be. It's hard to say that the data is clearly wrong. It does look a lot like Au foil, but with a much, much lower sigma2, or much higher energy resolution or mean-free-path or something else to increase the amplitude in a k-dependent way . It's hard to see how any measurement problem would give such an artifact, but we don't know a lot about how the measurements were made. Obviously, a clearer data file would be helpful, as would more information about the sample and measurements. What values do you get for sigma2? You said the values were not sensible, but you didn't say what that was. You also said the amplitude was "huge, up to 80 in some cases". I have no idea what that means... Was the sample cold? Do you have multiple measurements that show the same amplitude behavior? --Matt