JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
@inproceedings{contreras-martinez:srf2021-suptev014,
author = {C. Contreras-Martinez and T.T. Arkan and T.N. Khabiboulline and Y.M. Pischalnikov and G.V. Romanov and R.P. Stanek and J.C. Yun},
% author = {C. Contreras-Martinez and T.T. Arkan and T.N. Khabiboulline and Y.M. Pischalnikov and G.V. Romanov and R.P. Stanek and others},
% author = {C. Contreras-Martinez and others},
title = {{SRF Cavity Tuners for 3.9 GHz Cryomodules for LCLS-II Project}},
booktitle = {Proc. SRF'21},
% booktitle = {Proc. 20th International Conference on RF Superconductivity (SRF'21)},
pages = {155--158},
eid = {SUPTEV014},
language = {english},
keywords = {cavity, cryomodule, operation, SRF, FEL},
venue = {East Lansing, MI, USA},
series = {International Conference on RF Superconductivity},
number = {20},
publisher = {JACoW Publishing, Geneva, Switzerland},
month = {10},
year = {2022},
issn = {2673-5504},
isbn = {978-3-95450-233-2},
doi = {10.18429/JACoW-SRF2021-SUPTEV014},
url = {https://jacow.org/srf2021/papers/suptev014.pdf},
abstract = {{Fermilab conducted testing of three 3.9 GHz cryomodules for the LCLS-II project that will operate in continuous wave mode. A fast/fine tuning component was added to the LCLS-II 3.9 GHz tuner design due to the cavity bandwidth of 130 Hz which consists of two encapsulated piezos. Several cavities faced problems with fast-tuner operations after cooldown to 2 K and tuning the cavities to 3.9 GHz in cryomodule 2. All the piezo actuators were in working conditions but the slow tuner ranges required to stretch some of the cavities to the operational 3.9 GHz frequency were too small to deliver the required preload on the piezos. This behavior can be attributed to several factors: setting the initial warm cavity frequency during production too high, pressure tests of the warm cryomodule could have changed cavity frequency; and the small bending and twisting of the cavity-tuner system during the cooldown and warmup of the cavities. A decision was made to inelastically retune the warm cavities to decrease the unrestrained frequency by 200-300 kHz, this was done via the slow tuner. The results for this retuning method of three 3.9GHz cryomodules will be discussed.}},
}