High power breakdown testing of a photon

This study investigates an improved single-cell photonic band-gap accelerator structure featuring an inner row of elliptical rods, designated as PBG-E. The objective was to assess the structure's performance under high power conditions at a X-band frequency (11.424 GHz), focusing on its gradient and breakdown probability. The methodology involved rigorous testing at a 60 Hz repetition rate, revealing a gradient of 128 MV/m with a breakdown probability of approximately 3.6 x 10^-3 per pulse per meter at a pulse length of 150 ns. The results indicated that the PBG-E structure effectively reduced peak surface magnetic fields by 20% and minimized temperature rise during operation compared to earlier rod designs. Notably, the breakdown rate was comparable to that of a reference single-cell standing-wave undamped structure tested under the same conditions. Post-testing inspections revealed surface damage, yet no significant change in breakdown rates was observed. These findings suggest that PBG structures, when optimized for lower surface magnetic fields and appropriate pulsed heating conditions, can achieve performance metrics on par with conventional undamped accelerator designs, indicating their potential for high-gradient applications.