Phase Noise Measurements in SLAC Linac

The Linac Coherent Light Source that is under development at SLAC will become the world's first x-ray free electron laser. This laser will enable revolutionary studies in many different areas of science. Before the laser goes into operation at SLAC, phase noise measurements need to be taken to determine whether the existing linac structure will be able to run the LCLS. The phase noise of a system is translated into timing jitter, and the LCLS can only tolerate a certain amount of jitter. The measurements taken on the linac were higher than expected and we hypothesized that our measuring devices might have been the source of high noise readings. After designing new low noise amplifiers to amplify the signal, the phase noise and timing jitter levels went down. We were able to target the PEP phase shifter as the component of the linac system that was adding a lot of noise. More work needs to be done to further reduce the phase noise and timing jitter levels