Speaker
Description
During commissioning of the cavity-based free-electron laser (CBXFEL) project at SLAC, we observed ring-like and two-lobe optical/UV radiation patterns on a screen downstream of a dipole in the CBXFEL undulator line. Understanding the origin of this background is important for interpreting radiation diagnostics and may also enable a non-invasive probe of beam properties. We developed a theoretical and numerical model based on the frequency-domain Liénard–Wiechert field, including coherent synchrotron radiation, coherent edge radiation, microbunching-induced enhancement, and finite transverse beam-size effects. The model shows that coherent edge radiation, combined with the finite transverse size of the electron beam, can produce structured screen patterns consistent with the experimental observations. These results provide a framework for identifying bend-induced background radiation in CBXFEL beamlines and suggest potential beam diagnostic applications based on the observed radiation patterns.
| I have read and accept the Privacy Policy Statement | Yes |
|---|