Measurement of Coherent Off-axis Undulator Radiation as a Beam Diagnostic
نویسندگان
چکیده
* Corresponding author. Tel.: +301-405-4977. Email [email protected]. Abstract A diagnostic undulator is used to measure relative electron bunch lengths. The radiation produced by the short undulator is observed off-axis so that the beam is not interrupted. Wavelengths radiated which are longer than the bunch length are coherent and may be more intense than the shorter wavelengths by a factor of up to 10. The total energy radiated thus changes as the bunch length changes, and a measurement of the radiated energy provides a robust beam diagnostic. This non-disturbing diagnostic would be useful in applications where the length of short electron bunches is critical, such as singlepass FELs and linear colliders. For example, real-time bunch length measurements could be used to optimize performance of a single-pass FEL. The experiment is performed at the Source Development Lab (SDL) at Brookhaven National Laboratory. The theory and description of the experiment are reviewed, and the first experimental results are presented.
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