SRF2013 - List of Keywords (storage-ring)

Paper	Title	Other Keywords	Page
MOP003	Implications of Increased Beam Current for the Diamond Storage Ring RF System	cavity, operation, cathode, linac	73
	C. Christou, A. Bogusz, P. Gu, M. Maddock, P.J. Marten, S.A. Pande, A.F. Rankin, D. Spink, A.V. Watkins Diamond, Oxfordshire, United Kingdom
	Diamond Light Source presently operates for users with 300mA beam current and initial tests have begun to upgrade this current towards an ultimate goal of 500mA. The implications of such a beam current increase for the storage ring RF system will be significant, including the installation of a third superconducting cavity and a possible modification of the coupling parameters of the existing cavities. An overview of the planned enhancements of the RF system is presented, including an update of the procurement of a new CESR-design cavity and options for installation and operation of this cavity and supporting infrastructure.

MOP022	Preliminary Design of CEPC RF Superconducting System	cavity, HOM, impedance, cryogenics	140
	H.J. Zheng, J. Gao, S. Jin, Y. Liu, Z.C. Liu, J.Y. Zhai, T.X. Zhao IHEP, Beijing, People's Republic of China
	In order to study Higgs Boson, scientists proposed to construct a Higgs factory. Chinese scientists are also actively involved in research of the construction of Higgs factory. Construction of a circular collider and several construction solutions were proposed. Electron and positron are eventually accelerated to the center of mass energy 240GeV. RF superconducting acceleration system is indispensable to ensure the normal operation of machine. This article mainly introduces the RF parameters in the design of 700MHz China Higgs Factory (CHF) system. It mainly includes choose of cavity type, couplers and relevant parameters of cryogenic system.

THP062	Optimisation of the 3-Stub Tuner for Matching the Diamond SCRF Cavities	cavity, simulation, operation, coupling	1061
	S.A. Pande, C. Christou, P. Gu, M. Jensen Diamond, Oxfordshire, United Kingdom
	The Diamond Storage Ring cavities are aperture coupled resulting in a fixed external Q. This results in the cavities being matched under certain conditions depending on the loss per turn, the beam current and the accelerating voltage. Operationally, there are advantages to limiting the accelerating voltage to improve reliability and lifetime, which at high beam current results in a mismatch and high reflected power. To match the cavities under such non-optimum operating conditions we use 3-stub tuners in the waveguide feeds. It has been observed, that certain configurations of the 3-stub tuners can improve the match of the cavity, but this can result in strong heating of the waveguide in the cryostat. Numerical simulations of the cavity along with the coupling waveguide and 3-stub tuners have been carried out using CST Studio for different beam loading conditions to optimise the 3-stub tuners for acceptable match and heating. In this paper we present the results of our simulations and comparisons with measurements for operation with different beam currents and cavity voltages.

THP082	Fast Detuning Experiment on an SRF Cavity	cavity, cryomodule, experiment, resonance	1118
	G. Wu, N.D. Arnold, T.G. Berenc, J. Carwardine, A.R. Cours, J.D. Fuerst, J.P. Holzbauer, D. Horan, A. Nassiri ANL, Argonne, USA J. Matalevich JLAB, Newport News, Virginia, USA Y. Yang TUB, Beijing, People's Republic of China
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. Short Pulse X-ray beamlines occupy a limited number of sectors after the APS Upgrade. The majority of APS users will not participate in the SPX experiment. As user operation requires the best beam availability, it is important that any SPX-related circuit trip that requires the extinguishment of rf power should not affect overall beam availability. As such, it is necessary to de-couple the SRF cavities from beam when such an rf trip happens. An example of such trip is that the rf window arcing has to be stopped within 1 ms, before serious damage occurs to the ceramic. As the rf amplifier shuts down the rf output, beam-driven cavity power has to be reduced, too. If cavity can be detuned fast enough and far enough away from its resonance, the beam does not have to be aborted. The SPX0 tuner is equipped with a fast response Piezo actuator in the cavity tuner stack. Such a Piezo may be able to provide a quick jolt of the cavity to provide detuning capability for the purpose of maintaining the beam in the event of an rf trip. In this paper, we describe the experimental setup and results obtained, and discuss its effectiveness for beam operation.

Paper

Title

Other Keywords

Page

MOP003

Implications of Increased Beam Current for the Diamond Storage Ring RF System

cavity, operation, cathode, linac

73

C. Christou, A. Bogusz, P. Gu, M. Maddock, P.J. Marten, S.A. Pande, A.F. Rankin, D. Spink, A.V. Watkins
Diamond, Oxfordshire, United Kingdom

Diamond Light Source presently operates for users with 300mA beam current and initial tests have begun to upgrade this current towards an ultimate goal of 500mA. The implications of such a beam current increase for the storage ring RF system will be significant, including the installation of a third superconducting cavity and a possible modification of the coupling parameters of the existing cavities. An overview of the planned enhancements of the RF system is presented, including an update of the procurement of a new CESR-design cavity and options for installation and operation of this cavity and supporting infrastructure.

MOP022

Preliminary Design of CEPC RF Superconducting System

cavity, HOM, impedance, cryogenics

140

H.J. Zheng, J. Gao, S. Jin, Y. Liu, Z.C. Liu, J.Y. Zhai, T.X. Zhao
IHEP, Beijing, People's Republic of China

In order to study Higgs Boson, scientists proposed to construct a Higgs factory. Chinese scientists are also actively involved in research of the construction of Higgs factory. Construction of a circular collider and several construction solutions were proposed. Electron and positron are eventually accelerated to the center of mass energy 240GeV. RF superconducting acceleration system is indispensable to ensure the normal operation of machine. This article mainly introduces the RF parameters in the design of 700MHz China Higgs Factory (CHF) system. It mainly includes choose of cavity type, couplers and relevant parameters of cryogenic system.

THP062

Optimisation of the 3-Stub Tuner for Matching the Diamond SCRF Cavities

cavity, simulation, operation, coupling

1061

S.A. Pande, C. Christou, P. Gu, M. Jensen
Diamond, Oxfordshire, United Kingdom

The Diamond Storage Ring cavities are aperture coupled resulting in a fixed external Q. This results in the cavities being matched under certain conditions depending on the loss per turn, the beam current and the accelerating voltage. Operationally, there are advantages to limiting the accelerating voltage to improve reliability and lifetime, which at high beam current results in a mismatch and high reflected power. To match the cavities under such non-optimum operating conditions we use 3-stub tuners in the waveguide feeds. It has been observed, that certain configurations of the 3-stub tuners can improve the match of the cavity, but this can result in strong heating of the waveguide in the cryostat. Numerical simulations of the cavity along with the coupling waveguide and 3-stub tuners have been carried out using CST Studio for different beam loading conditions to optimise the 3-stub tuners for acceptable match and heating. In this paper we present the results of our simulations and comparisons with measurements for operation with different beam currents and cavity voltages.

THP082

Fast Detuning Experiment on an SRF Cavity

cavity, cryomodule, experiment, resonance

1118

G. Wu, N.D. Arnold, T.G. Berenc, J. Carwardine, A.R. Cours, J.D. Fuerst, J.P. Holzbauer, D. Horan, A. Nassiri
ANL, Argonne, USA
J. Matalevich
JLAB, Newport News, Virginia, USA
Y. Yang
TUB, Beijing, People's Republic of China

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Short Pulse X-ray beamlines occupy a limited number of sectors after the APS Upgrade. The majority of APS users will not participate in the SPX experiment. As user operation requires the best beam availability, it is important that any SPX-related circuit trip that requires the extinguishment of rf power should not affect overall beam availability. As such, it is necessary to de-couple the SRF cavities from beam when such an rf trip happens. An example of such trip is that the rf window arcing has to be stopped within 1 ms, before serious damage occurs to the ceramic. As the rf amplifier shuts down the rf output, beam-driven cavity power has to be reduced, too. If cavity can be detuned fast enough and far enough away from its resonance, the beam does not have to be aborted. The SPX0 tuner is equipped with a fast response Piezo actuator in the cavity tuner stack. Such a Piezo may be able to provide a quick jolt of the cavity to provide detuning capability for the purpose of maintaining the beam in the event of an rf trip. In this paper, we describe the experimental setup and results obtained, and discuss its effectiveness for beam operation.