Evaluation of Bunch Length by Measuring Coherent Synchrotron Radiation with a Narrow-Band Detector at LEBRA

Abstract

This study presents a novel technology to measure electron bunch length with a high time resolution by measuring coherent synchrotron radiation using a narrow-band detector at Laboratory for Electron Beam Research and Application (LEBRA)—an S-band linear accelerator facility for free-electron lasers. The form factor was observed to decrease exponentially with charge—in concordance with the relationship between the intensity of the coherent synchrotron radiation and the magnitude of electron bunch charge—in the region in which the effect of electron bunch charge on bunch length is negligible. The calculated root-mean-square bunch length was observed to agree well with the value determined from the spectral shape obtained. The aforementioned results are expected to be useful in real-time observation of small changes in electron bunches in advanced accelerators.

Terahertz as a Frontier Area for Science and Technology

“…Correlated with this research, the manuscript by Sakai and co-workers [34] is an original study that introduces a new technology to measure electron bunch length at high time resolutions. Using the coherent synchrotron radiation (CSR) emission, they evaluated the RMS bunch lengths in full-bunch mode and in burst mode.…”

Degradation of Lignin by Infrared Free Electron Laser

“…One macro-pulse bunches several thousand micro-pulses, and the duration of each micro-pulse is less than 1 ps. The repetition rates of mid-IR FEL and near-IR FEL are both 2856 MHz in the full-bunch mode [31]. The FEL pulse energy integrated over the macro-pulse ranges from 1 to 20 mJ, and the beam diameter was set to about 300-400 µm above the sample surface using an off-axis parabolic mirror or a focusing lens (CaF 2 ).…”