IPAC2021 - List of Authors (Timko, H.)

Paper	Title	Page
TUXC03	Ferro-Electric Fast Reactive Tuner Applications for SRF Cavities	1305
	N.C. Shipman, A. Castilla, M.R. Coly, F. Gerigk, A. Macpherson, N. Stapley, H. Timko CERN, Meyrin, Switzerland I. Ben-Zvi BNL, Upton, New York, USA G. Burt, A. Castilla Cockcroft Institute, Lancaster University, Lancaster, United Kingdom C.-J. Jing, A. Kanareykin Euclid TechLabs, Solon, Ohio, USA
	A Ferro-Electric fast Reactive Tuner (FE-FRT) is a novel type of RF cavity tuner containing a low loss ferroelectric material. FE-FRTs have no moving parts and allow cavity frequencies to be changed extremely quickly (on the timescale of 100s of ns or less). They are of particular interest for SRF cavities as they can be placed outside the liquid helium environment and without an FE-FRT it’s typically very difficult to tune SRF cavities quickly. FE-FRTs can be used for a wide variety of use cases including microphonics suppression, RF switching, and transient beam loading compensation. This promises entirely new operational capabilities, increased performance and cost savings for a variety of existing and proposed accelerators. An overview of the theory and potential applications will be discussed in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXC03
About •	paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 25 August 2021
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THXA07	Driven 3D Beam Oscillations for Optics Measurements in Synchrotrons	3704
	L. Malina, J.M. Coello de Portugal, H. Timko, R. Tomás García CERN, Geneva, Switzerland
	Optics measurements in storage rings employ turn-by-turn data of transversely excited beams. Traditionally, to measure chromatic properties, the relative momentum is changed step-wise, which is time-consuming and almost impractical during the energy ramp. We present an optics measurement method based on adiabatic simultaneous 3-dimensional beam excitation, which is more time-efficient and well fitted for the energy ramp. This method was successfully demonstrated in the LHC utilising AC-dipoles in combination either with a slow RF-frequency modulation or a driven RF-phase modulation close to the synchrotron frequency. Faster longitudinal oscillations improve the accuracy of optics parameters inferred from the synchro-betatron sidebands. This paper reports on the experimental demonstration of optics measurements based on 3D driven beam excitations and the plans for LHC Run 3.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXA07
About •	paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 11 August 2021
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THPAB199	Studies of Longitudinal Beam Losses at LHC Injection	4164
	L.E. Medina Medrano, T. Argyropoulos, R. Calaga, H. Timko CERN, Meyrin, Switzerland
	Funding: Research supported by the HL-LHC project. Due to higher beam intensities, the required rf power in the High-Luminosity LHC (HL-LHC) era is expected to be at the limit of the available rf power. To mitigate potential limitations of the rf system, the injection voltage can be reduced at the expense of beam losses. In this paper, the average and bunch-by-bunch losses are estimated from Run 2 beam intensity measurements in the SPS before extraction and in the LHC after injection. Macro-particle simulations are performed with CERN’s Beam Longitudinal Dynamics code to reproduce the observed SPS-to-LHC capture and LHC flat-bottom losses. First estimates of injection losses for the HL-LHC at different injection voltages and injection energy errors are discussed.
	Poster THPAB199 [2.428 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB199
About •	paper received ※ 18 May 2021 paper accepted ※ 28 July 2021 issue date ※ 14 August 2021
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THPAB200	Cavity Control Modelling for SPS-to-LHC Beam Transfer Studies	4168
	L.E. Medina Medrano, T. Argyropoulos, P. Baudrenghien, H. Timko CERN, Meyrin, Switzerland
	Funding: Research supported by the HL-LHC project. To accurately simulate injection losses in the LHC and the High-Luminosity LHC era, a realistic beam distribution model at SPS extraction is needed. To achieve this, the beam-loading compensation by the SPS cavity controller has to be included, as it modulates the bunch positions with respect to the rf buckets. This dynamic cavity control model also allows generating a more realistic beam halo, from which the LHC injection losses will mainly originate. In this paper, the implementation of the present SPS cavity controller in CERN’s Beam Longitudinal Dynamics particle tracking code is described. Just like in the machine, the feedback and feedforward controls are included in the simulation model, as well as the generator-beam-cavity interaction. Benchmarking against measurements of the generated beam distributions at SPS extraction are presented.
	Poster THPAB200 [4.164 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB200
About •	paper received ※ 18 May 2021 paper accepted ※ 27 July 2021 issue date ※ 26 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Ferro-Electric Fast Reactive Tuner Applications for SRF Cavities

1305

N.C. Shipman, A. Castilla, M.R. Coly, F. Gerigk, A. Macpherson, N. Stapley, H. Timko
CERN, Meyrin, Switzerland
I. Ben-Zvi
BNL, Upton, New York, USA
G. Burt, A. Castilla
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
C.-J. Jing, A. Kanareykin
Euclid TechLabs, Solon, Ohio, USA

A Ferro-Electric fast Reactive Tuner (FE-FRT) is a novel type of RF cavity tuner containing a low loss ferroelectric material. FE-FRTs have no moving parts and allow cavity frequencies to be changed extremely quickly (on the timescale of 100s of ns or less). They are of particular interest for SRF cavities as they can be placed outside the liquid helium environment and without an FE-FRT it’s typically very difficult to tune SRF cavities quickly. FE-FRTs can be used for a wide variety of use cases including microphonics suppression, RF switching, and transient beam loading compensation. This promises entirely new operational capabilities, increased performance and cost savings for a variety of existing and proposed accelerators. An overview of the theory and potential applications will be discussed in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXC03

About •

paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 25 August 2021

Export •

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

THXA07

Driven 3D Beam Oscillations for Optics Measurements in Synchrotrons

3704

L. Malina, J.M. Coello de Portugal, H. Timko, R. Tomás García
CERN, Geneva, Switzerland

Optics measurements in storage rings employ turn-by-turn data of transversely excited beams. Traditionally, to measure chromatic properties, the relative momentum is changed step-wise, which is time-consuming and almost impractical during the energy ramp. We present an optics measurement method based on adiabatic simultaneous 3-dimensional beam excitation, which is more time-efficient and well fitted for the energy ramp. This method was successfully demonstrated in the LHC utilising AC-dipoles in combination either with a slow RF-frequency modulation or a driven RF-phase modulation close to the synchrotron frequency. Faster longitudinal oscillations improve the accuracy of optics parameters inferred from the synchro-betatron sidebands. This paper reports on the experimental demonstration of optics measurements based on 3D driven beam excitations and the plans for LHC Run 3.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXA07

About •

paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 11 August 2021

Export •

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

THPAB199

Studies of Longitudinal Beam Losses at LHC Injection

4164

L.E. Medina Medrano, T. Argyropoulos, R. Calaga, H. Timko
CERN, Meyrin, Switzerland

Funding: Research supported by the HL-LHC project.
Due to higher beam intensities, the required rf power in the High-Luminosity LHC (HL-LHC) era is expected to be at the limit of the available rf power. To mitigate potential limitations of the rf system, the injection voltage can be reduced at the expense of beam losses. In this paper, the average and bunch-by-bunch losses are estimated from Run 2 beam intensity measurements in the SPS before extraction and in the LHC after injection. Macro-particle simulations are performed with CERN’s Beam Longitudinal Dynamics code to reproduce the observed SPS-to-LHC capture and LHC flat-bottom losses. First estimates of injection losses for the HL-LHC at different injection voltages and injection energy errors are discussed.

Poster THPAB199 [2.428 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB199

About •

paper received ※ 18 May 2021 paper accepted ※ 28 July 2021 issue date ※ 14 August 2021

Export •

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

THPAB200

Cavity Control Modelling for SPS-to-LHC Beam Transfer Studies

4168

L.E. Medina Medrano, T. Argyropoulos, P. Baudrenghien, H. Timko
CERN, Meyrin, Switzerland

Funding: Research supported by the HL-LHC project.
To accurately simulate injection losses in the LHC and the High-Luminosity LHC era, a realistic beam distribution model at SPS extraction is needed. To achieve this, the beam-loading compensation by the SPS cavity controller has to be included, as it modulates the bunch positions with respect to the rf buckets. This dynamic cavity control model also allows generating a more realistic beam halo, from which the LHC injection losses will mainly originate. In this paper, the implementation of the present SPS cavity controller in CERN’s Beam Longitudinal Dynamics particle tracking code is described. Just like in the machine, the feedback and feedforward controls are included in the simulation model, as well as the generator-beam-cavity interaction. Benchmarking against measurements of the generated beam distributions at SPS extraction are presented.

Poster THPAB200 [4.164 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB200

About •

paper received ※ 18 May 2021 paper accepted ※ 27 July 2021 issue date ※ 26 August 2021

Export •

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