Speaker
Description
At the Photo Injector Test facility at DESY in Zeuthen, Longitudinal Phase
Space (LPS) tomography is done to reconstruct the LPS before the booster. In
order to improve the existing technique, methodical studies were done where
some core concerns were addressed e.g. booster phase scan range, momentum
resolution and space-charge effects. An analytical model was developed to
quantify RMS energy spread, bunch length and phase advance. Phase advance
analysis determined the booster phase range and step size to be used for
obtaining momentum projections. The signal resolution of these projections
was improved by careful beta function control at the reference screen of the
momentum measurements. The reconstruction method was updated from algebraic
reconstruction technique to image space reconstruction algorithm and an
initial scientific presumption of LPS from low energy section momentum
measurements was established. The aforementioned reforms resulted in reduced
noise-like artefacts, better convergence speed and accurate longitudinal
emittance. The method was tested on simulations as well as on experimental
data. It can diagnose not only linear chirp in LPS but also higher order
effects. Experiment with modulated laser beam was also designed to
demonstrate the diagnostic capability.
