Speaker
Description
Understanding femtosecond longitudinal electron bunch properties including the temporal profile and slice parameters, together with the synchronisation to an external laser system is of key importance for accelerators operating with ultrashort bunches, such as UED machines, FELs, LWFAs. A well-established route to measuring these properties is to use radio-frequency transverse-deflecting cavities (TDCs) coupled with a dipole spectrometer. These metre-scale components, however, necessitate powerful and costly klystrons, and relative-to-laser temporal diagnostics are hindered by uncorrelated RF-laser timing jitter. To overcome these challenges, higher-frequency transverse-deflecting structures, driven by laser-generated THz radiation have emerged as a promising alternative. Current demonstrations, however, have been limited to proof-of-principle laboratory experiments, operating at electron energies of 4.5 MeV and below, and typically using femtocoulomb-scale charges.
Here, we present work on the design of a commercial prototype THz-driven transverse streaking device. Our compact prototype encompasses the full THz-streaking system, including a vacuum chamber housing a 10 cm long dielectric-lined waveguide (DLW) interaction structure with integrated coupler, precision vacuum alignment system, THz generation crystal, and laser transport components. Our standalone THz streaker requires minimal beamline space and is designed to operate using a commercially available 10 mJ laser amplifier, making it widely accessible for typical accelerator facilities.
We report on the optimisation of DLWs for efficient transverse streaking, using simulations of the internal EM fields and electron propagation. We show how the dispersion curve of the structure can be engineered through optimising the cross-sectional geometry, leading to prolonged interaction lengths with minimised sensitivity to fabrication tolerances. We also investigate the field uniformity, tuneability, and operating frequency of the structure. Simulations of our device predict that a temporal resolution of 34 fs using a 100 MeV, 1 mm-mrad emittance beam will be achieved, placing it in the regime of RF-driven TDCs, using an innately laser-synchronised measurement.
| Presenting Author | Joseph Bradbury |
|---|---|
| Is the Presenting Author a PhD Student or Early Career Scientist ? | Yes |
| Area of research | Accelerator technology (including magnets) |