Agustin Romero
Email: ar1@stanford.edu
Google Scholar: https://scholar.google.com/citations?user=d90AoQcAAAAJ
ORCID: https://orcid.org/0000-0002-9920-231X
Ultra-fast transverse beam orbit control in LCLS copper linac. Part I
https://iopscience.iop.org/article/10.1088/1748-0221/17/11/P11031/pdf
Current and future experiments at LCLS require x-ray pulse trains of variable time separation on the nanosecond scale. For instance, the cavity-based XFEL (CBXFEL) will use up to 4 pulses separated by 218.5 ns, the X-ray Laser Oscillator (XLO) will use 15 to 25 ns spaced pulses, and the Matter under Extreme Conditions (MEC) experiments use pulse trains separated by 5 nanoseconds or less. In this paper, we demonstrate an ultra-fast e-beam trajectory control method based on transverse electro-magnetic (TEM) striplines and state-of-the-art power sources, to enhance LCLS operations in these regimes.
LCLS MULTI-BUNCH IMPROVEMENT PLAN: FIRST RESULTS
https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT037
https://jacow.org/ipac2022/papers/tupopt037.pdf
LCLS copper linac primarily operates in a single bunch mode with a repetition rate of 120 Hz. Presently, several inhouse projects and LCLS user experiments require double- and multi-pulse trains of X-rays, with inter-pulse delay spanning between 0.35 and 220 ns. We discuss beam control improvements to the copper linac using ultra-fast stripline kicker, as well as additional photon diagnostics. We especially focus on a case of double-pulse mode, with 220 ns separation.
High Efficiency Traveling Wave Linac With Tunable Energy
https://accelconf.web.cern.ch/linac2022/papers/thpojo16.pdf
We will present the physics design of a compact, highly efficient, energy-tunable 9.3 GHz linac to generate up to 500 W of 10 MeV electron beam power for medical and security applications. This linac will employ a patented travelling wave accelerating structure with outside power flow which combines the advantages of high efficiency with energy tunability of traveling wave cavities. Unlike standing wave structures, the proposed structure has little power reflected back to the RF source, eliminating the need for a heavy, lossy waveguide isolator. In contrast to the side-coupled cavity designs, the proposed structure is symmetrical and therefore it does not have deflecting axial fields that impair the beam transport. The high shunt impedance will allow the linac to achieve an output energy of up to 10 MeV when powered by a compact commercial 9.3 GHz 1.7 MW magnetron. For pulse-to-pulse tuning of the beam output energy we will change the beam-loaded gradient by varying the linac's triode gun current.