Noise reduction for the infrared beamline at the Advanced Light Source

Significant reductions in the noise of the infrared light have been made at Beamline 1.4.3 infrared source at the Advanced Light Source (ALS). The primary source of vibrational noise has been identified as the water system for the storage ring RF system, which is located near the beamline. Modifications to this system have reduced the noise by an order of magnitude. The dominant source of higher frequency noise has been identified as phase noise in the RF master oscillator driving synchrotron oscillations of the beam. We present measurements of the effect of the electron beam motion in a Fourier transform interferometer (FTIR) detector and a discussion of the coupling mechanism to the beam.