Feasibility studies of an inverse compton scattering based gamma source at MESA

Abstract

Recent years saw a number of accelerator projects attempt to utilize Inverse Compton Scattering (ICS) as gamma sources and beam diagnostic tools. With it's low cross section, ICS is a prospective pairing with energy recovery linacs (ERL) as they require low impact experiments for energy recovery efficiency to be high.\\ At the Johannes Gutenberg-University Mainz, the Mainz Energy Recovering Superconducting Linear Accelerator (MESA) is under construction. To investigate the potential of an ICS experiment at MESA, the task was given to conduct a feasibility study for ICS at MESA. In this thesis, the mathematical foundation of ICS as a relativistic particle collision between fermions and photons is summarized and derived. On this foundation, a semi-analytical numerical ICS simulation code named Comparse was written. It's principles and focus on performance are described in a chapter of it's own. Three positions in the accelerator layout possibly suitable for an ICS experiment were identified in the plans and beam line simulations according to which MESA is currently under construction. Using beam parameters in these locations, a number of ICS performance studies were conducted with Comparse. Through various investigated implementation scenarios, a detailed picture of MESA's potential as the driver for a ICS gamma source is formed. We have shown that with minimal effort, MESA can drive a E_ph' > 200 keV or lambda < 6.2 pm photon source with a flux of at least F >14.000 ph/s. At the other end of the scale, assuming moderate modifications to the MESA beamline and an amplified lambda = 193 nm laser, we project the potential for a F > 5*10^8 ph/s gamma source above 1 MeV photon energy. Finally, we present various aspects of ICS experiment that impact the performance, including polarization effects. With this thesis, we have thus provided a rare comprehensive review of the interdependence of the ICS behavior between polarization, scattering and incident angles as well as recoil and momentum distribution.