Successful First Run with New Deflecting Cavity on VELA

The first commissioning with beam has been made with the new Transverse Deflecting Cavity on VELA. Use of this cavity allows the longitudinal properties of the electron beam to be resolved, thus it forms a key component in the suite of diagnostics tools on VELA to enable full 6-dimensional phase space characterization of the electron bunches produced by the photo injector electron gun. The photograph below shows the installed cavity in the accelerator.


Installed cavity in the accelerator.

Initial measurements taken using the Transverse Deflecting Cavity show the VELA electron bunch length to be of the picosecond to sub-picosecond scale, varying with bunch charge, with results similar to simulations. Knowledge of the bunch length is important for further experiments on VELA, such as electron diffraction. In addition, Understanding how to use this type of device to measure the temporal beam properties will be vital in delivering the high quality electron bunches needed for future FELs such as CLARA.

The transverse deflecting cavity was designed by CI members ASTeC, STFC Technical Department, and The University of Lancaster.