21–26 Jul 2024
NIU Naperville Conference Center
US/Central timezone

Analytical and Numerical Studies of Dark Current in Radiofrequency Structures for Wakefield Acceleration

23 Jul 2024, 18:00
1h 30m
NIU Naperville Conference Center

NIU Naperville Conference Center

1120 E. Diehl Road, Ste 150, Naperville IL 60563

Speaker

Mr Gaurab Rijal (Northern Illinois University)

Description

RF breakdown limits the attainable acceleration gradient in normal conducting RF structures, challenging high-gradient operations. Recent experiments at the Argonne Wakefield Accelerator (AWA) suggest short RF pulses (a few nanoseconds) can mitigate this breakdown. We simulated dark current emission in the short-pulse regime to study breakdown initiators including field emission and multipacting. This study integrates analytical and numerical modeling of dark electron generation to understand multipacting and RF breakdown in structures driven by short RF pulses. We simulated electron trajectories under various conditions in the electromagnetic fields. Our analytical model, compared against simulations, predicted multipacting resonance modes and secondary electron yield. Our findings have revealed the dependence of dark current generation on the RF field strength, pulse duration, and surface properties. These insights guide the design of RF structures with enhanced performance and reduced breakdown susceptibility, advancing the next-generation short-pulse accelerators.

Working group WG4 : Novel structure acceleration

Primary author

Mr Gaurab Rijal (Northern Illinois University)

Co-authors

Xueying Lu (Northern Illinois Univ / Argonne National Laboratory) Michael Shapiro (MIT) John Power (Argonne National Lab)

Presentation materials

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