Noise reduction efforts for the infrared beamline at the Advanced Light Source

The quality of infrared microscopy and spectroscopy data collected at synchrotron based sources is strongly dependent on noise. We have successfully identified and suppressed several noise sources affecting Beamline 1.4.3 at the Advanced Light Source (ALS), resulting in significant reductions to the noise in the users´ FTIR spectra. In this paper, we present our methods of noise source analysis and the techniques used to reduce the noise and its negative effect on the infrared beam quality. These include analyzing and changing physical mounts to better isolate portions of the beamline optics from low-frequency environmental noise, and modifying the input signals to the main ALS RF system. We also discuss the relationship between electron beam energy oscillations at a point of dispersion and infrared beamline noise.