Paper | Title | Page |
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WETEB3 | CEBAF C100 Fault Classification based on Time Domain RF Signals | 763 |
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Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 The CEBAF 12 GeV upgrade project, which was completed and commissioned in 2014, included the construction and installation of 80 new 7-cell superconducting cavities that were configured in 10 cryomodules. In 2018, the software and hardware in the digital low level RF systems were configured such that a fault would trigger an acquisition process which records waveform records of 17 of the RF signals for each of the 8 cavities within the cryomodule for subsequent analysis. These waveforms are especially useful in C100 cryomodules as there is a 10% mechanical coupling between adjacent cavities. When one cavity has a fault and the gradient is reduced quickly, it will mechanically deform due relaxation of the Lorentz force effects. This deformation change causes perturbations in the adjacent cavities which, in turn, causes a cascade of cavity faults that are difficult to understand without the time domain data. This contribution will describe the types of faults encountered during operation and their signatures in the time domain data, as well as how is being used to modify the setup of the machine and implement improvements to the cryomodules. |
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Slides WETEB3 [3.169 MB] | |
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-WETEB3 | |
About • | paper received ※ 21 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019 | |
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THP049 | Commissioning the JLab LERF Cryomodule Test Facility | 973 |
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The JLab Low Energy Recirculating Facility, LERF, has been modified to support concurrent testing of two LCLS-II cryomodules. The cryomodules are installed in a similar fashion as they would be in the L1 section of the LCLS-II linac, including the floor slope and using all of the LCLS-II hardware and controls for cryomodule cryogenics, vacuum, and RF (SSA and LLRF). From the start, it was intended to use LCLS-II electronics and EPICS software controls for cryomodule testing. In affect the LERF test facility becomes the first opportunity to commission and operate the LCLS-II LINAC hardware and software controls. Support for specific cryomodule high level test applications like Q0 and HOMs measurements, are being developed from the basic cryomodule control suite. To support the testing, 2 K He is supplied from the CEBAF south linac cryogenic system, where care must be taken when using the LERF test facility to not upset the CEBAF cryogenics plant. This paper discusses the commissioning of the hardware and software development for testing the first two LCLS-II cryomodules. | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP049 | |
About • | paper received ※ 22 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019 | |
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THP056 | Current Results From Acceptance Testing of LCLS-II Cryomodules at Jefferson Lab | 1007 |
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Funding: This work was supported by the LCLS-II Project and the U.S. Department of Energy, Contract DE-AC02-76SF00515. The Thomas Jefferson National Accelerator Facility is currently engaged, along with several other Department of Energy (DOE) national laboratories, in the Linac Co-herent Light Source II project (LCLS-II). The SRF Insti-tute at Jefferson Lab is currently building 21 cryomod-ules for this project. The cryomodules are based on the XFEL design and have been modified for continuous wave (CW) operation and to comply with other LCLS-II specifications. Each cryomodule contains eight 9-cell cavities with coaxial power couplers operating at 1.3 GHz. The cryomodule also contain a magnet package that consists of a quadrupole and two correctors. Most of these cryomodules will be tested in the Cryomodule Test Facility (CMTF) at Jefferson Lab before shipment to SLAC. Up to three of these cryomodules will be tested in a test stand set up in the Low Energy Recovery Facility (LERF) at Jefferson Lab. Acceptance testing of the LCLS-II cryomodules began in December 2016. Twelve cryomodules have currently completed Acceptance Test-ing. This paper will summarize the results of those tests. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP056 | |
About • | paper received ※ 22 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019 | |
Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |