TUCOYBS01
KEK, Ibaraki, Japan
KEK, Ibaraki, Japan
Sokendai - Hayama, Hayama, Japan
Sokendai, Ibaraki, Japan
THCOXBS06
KEK, Ibaraki, Japan
| Paper | Title | Page |
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TUCOYBS01 |
KEK ERL SRF Operation Experience | |
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| We will present the SRF operation experience during long-term cERL operation in KEK. | ||
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Slides TUCOYBS01 [8.289 MB] | |
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| TUCOZBS04 | Characterization of Microphonics in the cERL Main Linac Superconducting Cavities | 48 |
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| In the main linac (ML) of the KEK-cERL, two superconducting cavities with high loaded Q (QL ¿ 1×107) are operated in continuous wave (CW) mode. It is important to control and suppress the microphonics detuning owing to the low bandwidth of the cavities. We evaluated the background microphonics detuning by the low level radio frequency system during the beam operation. Interestingly, a ¿field level dependence microphonics¿ phenomenon was observed on one of the cavities in the ML. Several frequency components were suddenly excited if the cavity field is above a threshold field (~3 MV/m). We found that this threshold field is probably related with the cavity quench limits despite the unclear inherent physical mechanism. Furthermore, in order to optimize the cavity resonance control system for better microphonics rejection, we have measured the mechanical transfer function between the fast piezo tuner and cavity detuning. Finally, we validated this model by comparing the model response with actual system response. | ||
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Slides TUCOZBS04 [7.564 MB] | |
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-TUCOZBS04 | |
| About • | paper received ※ 13 September 2019 paper accepted ※ 01 November 2019 issue date ※ 24 June 2020 | |
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THCOXBS06 |
Degradation and Recovery of Cavity Performance in Compact-ERL Injector Cryomodule at KEK | |
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| After cryomodule assembly and first cool-down tests in 2012, the cERL injector cryomodule has been stably operated with beam for eight years. However, gradual increases of x-ray radiation levels due to field emission were observed during the long term beam operation. High power pulsed RF conditioning as a cure method was firstly applied in the cool-down period in 2016, so that degraded cavity performances have almost recovered up to the previous levels. After that, high power pulsed RF conditioning has been repeatedly carried out as a standard procedure in the beginning of the cool-down periods in 2017-2019. Performance degradation and recovery status during the long term beam operation will be presented in this talk. | ||
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Slides THCOXBS06 [8.011 MB] | |
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