Beamline detectors operating in the 100-1000Hz regime are becoming more common, and the X-ray beam stability demanded by beamlines is also thus of comparable bandwidths. In order to maintain the positional stability of a focussed X-ray beam at the beamline sample-point at bandwidths of up to ~500Hz, it is proposed to introduce a feedback system that makes adjustments to the X-ray source point (the electron beam) at these bandwidths, using X-ray beam position monitors as the feedback input.
Presently, it is extremely difficult for beamlines to correct beam motion at these frequencies with conventional beamline feedback, using optical components (monochromator, mirrors, etc) to steer the X-ray beam. Simply the mass of these components make them difficult to move and manipulate at >100Hz. The existing electron beam feedback, the “fast orbit feedback”, is less effective above about 200Hz, and in any case, this feedback knows nothing of the X-ray beam stability on the beamline itself.
Thus, it is proposed to develop a new system, monitoring the X-ray beam position on the beamline and making adjustments to the electron beam at ~500Hz, in order to improve the X-ray beam stability.