ERL2019 - List of Authors (Macpherson, A.)

Paper	Title	Page
TUCOZBS02	A Ferroelectric Fast Reactive Tuner (FE-FRT) to Combat Microphonics	42
	N.C. Shipman, J. Bastard, M.R. Coly, F. Gerigk, A. Macpherson, N. Stapley CERN, Meyrin, Switzerland I. Ben-Zvi BNL, Upton, New York, USA G. Burt, A. Castilla Lancaster University, Lancaster, United Kingdom C.-J. Jing, A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA E. Nenasheva Ceramics Ltd., St. Petersburg, Russia
	A prototype Fast Reactive Tuner (FRT) for superconducting cavities has been developed, which allows the frequency to be controlled by application of a potential difference across a newly developed ultra-low loss ferro-electric material residing within the tuner. The tuner operates at room temperature, outside of the cryostat and coupled to the cavity via an antenna and co-axial cable. This technique allows for active compensation of microphonics, eliminating the need to design over-coupled fundamental power couplers and thus significantly reducing RF power particularly for low beam current applications. Modelling; simulation; and stability analysis, of the tuner; cavity; measurement system; and feedback loop, have been performed in the frequency and time domain, and are compared to the latest experimental results. The potential benefits of applying this techniques to ERLs, which are seen as one of the major use cases, are detailed both in general and with regards to specific projects. Ideas and designs for an improved next generation FRT are also discussed.
	Slides TUCOZBS02 [5.607 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-TUCOZBS02
About •	paper received ※ 17 September 2019 paper accepted ※ 06 November 2019 issue date ※ 24 June 2020
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THCOXBS05	High Q 704 MHz Cavity Tests at CERN
	A. Macpherson CERN, Geneva, Switzerland
	Results from CERN’s bulk niobium high-gradient cavity development program at CERN are presented, with particular focus on evolution of RF performance 704 MHz bulk niobium 5-cell elliptical cavity prototypes originally produced for the Superconducting Proton Linac (SPL) project. Successive cold tests of bare cavities have been used to refine the cavity preparation and testing process, with all steps done in-house at CERN, and reproducible RF performance well above SPL specifications has been achieved. Current performance results are discussed in relation to cavity preparation and cold tests procedures, with reference to direct observables such as expelled flux and thermal gradients during cool down, field emission characteristics, and quench diagnostics. In addition, the processing of raw RF data from single pulse measurements to extract RF performance figures of merit will be presented, offering an alternative approach to assessing RF performance.
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

A Ferroelectric Fast Reactive Tuner (FE-FRT) to Combat Microphonics

42

N.C. Shipman, J. Bastard, M.R. Coly, F. Gerigk, A. Macpherson, N. Stapley
CERN, Meyrin, Switzerland
I. Ben-Zvi
BNL, Upton, New York, USA
G. Burt, A. Castilla
Lancaster University, Lancaster, United Kingdom
C.-J. Jing, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
E. Nenasheva
Ceramics Ltd., St. Petersburg, Russia

A prototype Fast Reactive Tuner (FRT) for superconducting cavities has been developed, which allows the frequency to be controlled by application of a potential difference across a newly developed ultra-low loss ferro-electric material residing within the tuner. The tuner operates at room temperature, outside of the cryostat and coupled to the cavity via an antenna and co-axial cable. This technique allows for active compensation of microphonics, eliminating the need to design over-coupled fundamental power couplers and thus significantly reducing RF power particularly for low beam current applications. Modelling; simulation; and stability analysis, of the tuner; cavity; measurement system; and feedback loop, have been performed in the frequency and time domain, and are compared to the latest experimental results. The potential benefits of applying this techniques to ERLs, which are seen as one of the major use cases, are detailed both in general and with regards to specific projects. Ideas and designs for an improved next generation FRT are also discussed.

Slides TUCOZBS02 [5.607 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-ERL2019-TUCOZBS02

About •

paper received ※ 17 September 2019 paper accepted ※ 06 November 2019 issue date ※ 24 June 2020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THCOXBS05

High Q 704 MHz Cavity Tests at CERN

A. Macpherson
CERN, Geneva, Switzerland

Results from CERN’s bulk niobium high-gradient cavity development program at CERN are presented, with particular focus on evolution of RF performance 704 MHz bulk niobium 5-cell elliptical cavity prototypes originally produced for the Superconducting Proton Linac (SPL) project. Successive cold tests of bare cavities have been used to refine the cavity preparation and testing process, with all steps done in-house at CERN, and reproducible RF performance well above SPL specifications has been achieved. Current performance results are discussed in relation to cavity preparation and cold tests procedures, with reference to direct observables such as expelled flux and thermal gradients during cool down, field emission characteristics, and quench diagnostics. In addition, the processing of raw RF data from single pulse measurements to extract RF performance figures of merit will be presented, offering an alternative approach to assessing RF performance.

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)