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- Goryashko, Vitaliy, 1982-, et al.
(författare)
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Proposal for Design and Test of a 352 MHz Spoke RF Source
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- More than a dozen of spoke resonators prototypes (SSR, DSR, TSR) have been constructed and tested worldwide. None have accelerated beam until now and the ESS LINAC will be the first accelerator to operate with spoke cavities. Experience with other types of superconducting cavities indicates that high-power test is vital for reliable operation of the cavity in an accelerator. Although characteristics of a bare cavity can be obtained in a low-power test some important features of a `dressed' cavity like the electroacoustic stability and tuning system can be studied only in a high-power test stand. The ESS LINAC is a pulsed machine and the Lorentz detuning originating from the electromagnetic pressure on the cavity walls is expected to be strong. The Lorentz force along with the cavity sensitivity to mechanical excitations at some resonant frequencies may lead to self-sustained mechanical vibrations which make cavity operation dicult. Practical experience shows that increasing the boundary stiness will decrease the static Lorentz force detuning but not necessarily the dynamic one. Therefore, the FREIA group at Uppsala University is building a high-power test stand able to study performance of the ESS spoke cavity at high power. The RF test stand will be able to drive the cavity not only in the self-excitation mode but also with closed RF loop and fixed frequency. The later technique will be used to reproduce the shape of the cavity voltage pulse as it is expected to be in the cavity operating in the ESS LINAC such that the cavity tuning compensation system will be tested under realistic conditions.
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| 2. |
- Junquera, Tomas, et al.
(författare)
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Design of a New Horizontal Test Cryostat for Scrfcavities at the Uppsala University
- 2014
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Ingår i: SRF2013: Proceedings of the 16th International Conference on RF Superconductivity. - 9783954501434 ; , s. 325-327
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- At Uppsala University, the FREIA facility for researchand development of new accelerators and associatedinstrumentation, is presently in construction. Associatedto a new Helium Liquefier, a Horizontal Test Cryostat willbe used for high power RF tests of completely equippedSC cavities. This paper presents the main characteristicsof the cryostat. Two types of cavities have beenconsidered for test purpose: SC elliptical cavities forfuture free electron lasers and SC cavities for highintensity proton accelerators. A special valve boxincluding a subcooling stage and power coupler coolingwith supercritical Helium supply have been designed, fortemperature operation ranging from 2 K to 4.2 K. Thisfacility will play an essential role in the development andtest of cavities, couplers and cryomodules for the ESSproject. High power RF sources will be installed in orderto allow unique and complete tests of spoke cavities andcryomodules at high nominal peak power.
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