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HIGH-PRECISION MEAS...
HIGH-PRECISION MEASUREMENTS OF THE QUALITY FACTOR OFSUPER CONDUCTING CAVITIES AT THE FREIA LABORATORY
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- Goryashko, Vitaliy (författare)
- Uppsala universitet,Högenergifysik,FREIA
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- Li, Han (författare)
- Uppsala universitet,Högenergifysik,FREIA
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- Nicander, H. (författare)
- Uppsala universitet,Högenergifysik,FREIA
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- Teerikoski, S. (författare)
- Uppsala universitet,Högenergifysik,FREIA
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- Gajewski, K. (författare)
- Uppsala universitet,Högenergifysik,FREIA
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- Hermansson, L. (författare)
- Uppsala universitet,Högenergifysik,FREIA
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- Santiago Kern, Rocio (författare)
- Uppsala universitet,Högenergifysik,FREIA
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- Ruber, Roger (författare)
- Uppsala universitet,Högenergifysik,FREIA
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- Dancila, Dragos (författare)
- Uppsala universitet,Högenergifysik,FREIA
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(creator_code:org_t)
- 2015
- 2015
- Engelska.
- Relaterad länk:
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https://uu.diva-port... (primary) (Raw object)
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https://urn.kb.se/re...
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Abstract
Ämnesord
Stäng
- The dependence of cavity quality factor Q0 on accelerating gradient gives insight into the intrinsic limit of RFsurface impedance that determines the cavity performance. In this paper we propose a high-precision method of measuringQ0 of SRF cavities. A common way to study the performance of an SRF cavity is to build an oscillator around it that is referred to as a self-excited loop. In the standard approach, by tuning the loop phase for a maximum field level in thecavity and measuring forward and reflected waves, one finds the cavity coupling. Then, performing a time-decay measurement and finding the total quality factor, one gets Q0. However, this approach suffers from a deficiency originating from a single data-point measurement of the reflection coefficient. In our method by varying the loop phase shift, one obtains amplitudes of the reflection coefficient of the cavity as a function of its phases. The complex reflection coefficient describes a perfect circle in polar coordinates. Fitting the overdetermined set of data to that circle allows more accurate calculation of Q0 via the least-squares procedure. The method has been tested at the FREIA Laboratory on two cavities from IPN Orsay: a single spoke and a prototype ESS double spoke.
Ämnesord
- NATURVETENSKAP -- Fysik -- Acceleratorfysik och instrumentering (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Accelerator Physics and Instrumentation (hsv//eng)
Publikations- och innehållstyp
- ref (ämneskategori)
- kon (ämneskategori)