[Ifeffit] S XANES question

[Matthew Marcus]

A user on ALS 10.3.2 is taking S K-edge XANES and consistently finding a strong peak at 2484eV (calibration: gypsum white line = 2482.75eV).
There's a shoulder at the nominal position of the sulfate peak.  Now, peaks below sulfate I can understand, but since there's no such
thing as heptavalent sulfur, what could give a peak *above* the sulfate white line?  Anybody ever seen that?  Yes, we checked calibration.
	mam