The LCLS-II HE superconducting linac can produce multi-energy beams by supporting multiple undulator lines simultaneously. This could be achieved by using the cavity SRF tuner in the off-frequency detune mode. This off-frequency operation method was tested in the verification cryomodule (vCM) and CM 1 at Fermilab at 2 K. In both cases, the tuners achieved a frequency shift of -565±80 kHz. This study will discuss cavity frequency during each step as it is being assembled in the cryomodule string and finally when it is being tested at 2 K. Tracking the cavity frequency helped enable the tuners to reach this large frequency shift. The specific procedures of tuner setting during assembly will be presented.
@article{arxiv.2208.06320,
title = {Tests Of The Extended Range SRF Cavity Tuners For The LCLS-II-HE Project*},
author = {C. Contreras-Martinez and T. Arkan and A. Cravatta and B. Hartsell and J. Kaluzny and T. Khabiboulline and Y. Pischalnikov and S. Posen and G. Romanov and JC. Yun},
journal= {arXiv preprint arXiv:2208.06320},
year = {2022}
}