Dear Mark, thanks for your answer! Yes, there is an actual change in energy and I guess my problem does not have a single source!
In the case you know someone who faced/have faced a similar problem around please tell me. Brazilian regards, LS. 1. Is the energy drift a change in flux or actual change in wavelength? In the case of a change in flux it could be that you require more cooling, what temperature is the cooling water at and how constant is the water temperature? You may need to lower the cooling water temperature. On beamline 10 at the SRS, the 1st mirror is cooled by the synchrotron deionised water supply at a temperature of ~20oC, however we cool the monochromator crystals on an independent water supply, typically at a temperature of 4oC. We do see a drastic shift in beam intensity when we go to wavelengths >2.2A (beam fluctuates wildly), consequently we limit operations to wavelengths between 0.875 and 2.1A. If it is a real change in energy/wavelength then there is a more serious problem. It would suggest a change in the beam entering the optical elements.
