| Title |
Narrow Bandwidth Active Noise Control for Microphonics Rejection in Superconducting Cavities at LCLS-II |
| Authors |
- A. Bellandi, J. Branlard
DESY, Hamburg, Germany
- S. Aderhold, A.L. Benwell, A. Brachmann, J.A. Diaz Cruzpresenter, D. Gonnella, S.L. Hoobler, J. Nelson, A. Ratti, L.M. Zacarias
SLAC, Menlo Park, California, USA
- J.A. Diaz Cruzpresenter
UNM-ECE, Albuquerque, USA
- R.D. Porter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
|
| Abstract |
LCLS-II is an X-Ray Free Electron Laser (XFEL) under commissioning at SLAC, being the first Continuous Wave (CW) hard XFEL in the world to come into operation. To accelerate the electron beam to an energy of 4 GeV, 280 superconducting cavities of the TESLA types are used. A Loaded Q (QL) value of 4x10⁷ is used to drive the cavities at a power level of a few kilowatts. For this QL value, the RF cavity bandwidth is equal to 32 Hz. Therefore, keeping the cavity resonance frequency within such bandwidth is imperative to avoid a significant increase in the required RF power. In superconducting accelerators, resonance frequency variations are produced by mechanical microphonic vibrations of the cavities. One source of microphonics noise is rotary machinery such as vacuum pumps or HVAC equipment. A possible method to reject these disturbances is to use Narrowband Active Noise Control (NANC) techniques. Such a technique was already tested at DESY/CMTB and Cornell/CBETA. This proceeding presents the implementation of a NANC controller in the LCLS-II Low Level RF (LLRF) control system. Tests on the rejection of LCLS-II microphonics disturbances are also presented.
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| Paper |
download THPOPA21.PDF [0.385 MB / 4 pages] |
| Poster |
download THPOPA21_POSTER.PDF [1.843 MB] |
| Cite |
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※ EndNote |
| Conference |
LINAC2022 |
| Series |
International Linear Accelerator Conference (31st) |
| Location |
Liverpool, UK |
| Date |
28 August-02 September 2022 |
| Publisher |
JACoW Publishing, Geneva, Switzerland |
| Editorial Board |
Peter McIntosh (STFC DL, Daresbury, UK); Graeme Burt (Lancaster Univ., Lancaster, UK); Robert Apsimon (Lancaster Univ., Lancaster, UK); Volker R.W. Schaa (GSI, Darmstadt, Germany) |
| Online ISBN |
978-3-95450-215-8 |
| Online ISSN |
2226-0366 |
| Received |
24 August 2022 |
| Revised |
30 August 2022 |
| Accepted |
02 September 2022 |
| Issue Date |
26 September 2022 |
| DOI |
doi:10.18429/JACoW-LINAC2022-THPOPA21 |
| Pages |
785-788 |
| Copyright |
 Published by JACoW Publishing under the terms of the Creative Commons Attribution 4.0 International license. Any further distribution of this work must maintain attribution to the author(s), the published article's title, publisher, and DOI. |
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