Mitigation of COTR due to the Microbunching Instability in Compressed Electron Beams

Abstract

We have demonstrated a technique to mitigate the intensity of the coherent OTR (COTR) relative to the OTR signals on the Advanced Photon Source chicane-compressed beams at 325 MeV. Since the reported spectral content of the COTR at LCLS after the first compression stage is similar, the concepts should also apply to LCLS. We utilized the stronger violet content at 400 nm of the OTR compared to the observed gain factors of the COTR in the green to NIR. We also demonstrated the use of an LSO:Ce scintillator that emits violet light to support lower-charge imaging