IPAC2022 - Classification: MC1: Circular and Linear Colliders / T12: Beam Injection/Extraction and Transport

Paper	Title	Page
WEPOST011	Studies on Top-Up Injection into the FCC-ee Collider Ring	1699
SUSPMF006	use link to see paper's listing under its alternate paper code
	P.J. Hunchak, M.J. Boland CLS, Saskatoon, Saskatchewan, Canada M. Aiba PSI, Villigen PSI, Switzerland W. Bartmann, Y. Dutheil, M. Hofer, R.L. Ramjiawan, F. Zimmermann CERN, Meyrin, Switzerland M.J. Boland University of Saskatchewan, Saskatoon, Canada
	In order to maximize the luminosity production time in the FCC-ee, top-up injection will be employed. The positron and electron beams will be accelerated to the collision energy in the booster ring before being injected with either a small transverse or longitudinal separation to the stored beam. Using this scheme essentially keeps the beam current constant and, apart from a brief period during the injection process, collision data can be continuously acquired. Two top-up injection schemes, each with on- and off-momentum sub-schemes, viable for FCC-ee have been identified in the past and are studied in further detail to find a suitable design for each of the four operation modes of the FCC-ee. In this paper, injection straight optics, initial injection tracking studies and the effect on the stored beam are presented. Additionally, a basic proxy error lattice is introduced as a first step to studying injection into an imperfect machine.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST011
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
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WEPOST013	Exploitation of Crystal Shadowing via Multi-Crystal Array, Optimisers and Reinforcement Learning	1707
	F.M. Velotti, M. Di Castro, L.S. Esposito, M.A. Fraser, S.S. Gilardoni, B. Goddard, V. Kain, E. Matheson CERN, Meyrin, Switzerland
	The CERN Super Proton Synchrotron (SPS) routinely delivers proton and heavy ion beams to the North experimental Area (NA) in the form of 4.8 s spills. To produce such a long flux of particles, resonant third integer slow extraction is used, which, by design, foresees primary beam lost on the electrostatic septum wires to separate circulating from extracted beam. Shadowing with thin bent crystal has been proposed and successfully tested in the SPS, as detailed in . In 2021, a thin crystal was used for physics production showing results compatible with what measured during early testing. In this paper, the results from the 2021 physics run are presented also comparing particle losses at extraction with previous operational years. The setting up of the crystal using numerical optimisers is detailed, with possible implementation of reinforcement learning (RL) agents to improve the setting up time. Finally, the full exploitation of crystal shadowing via multi-array crystals is discussed, together with the performance reach in the SPS. F.Velotti, et. al, "Septum shadowing by means of a bent crystal to reduce slow extraction beam loss", Phys. Rev. Accel. Beams 22, 093502 - Published 27 September 2019*
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST013
About •	Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 02 July 2022
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WEPOST025	A High Power Prototype of a Harmonic Kicker Cavity	1749
	G.-T. Park, G.A. Grose, J. Guo, A. OBrien, R.A. Rimmer, H. Wang, R.S. Williams JLab, Newport News, Virginia, USA S.A. Overstreet ODU, Norfolk, Virginia, USA
	A harmonic kicker, a beam exchange device that can deflect the beam at an ultra-fast time scale (a few ns), has been developed in Jefferson Lab , . The high power prototype that can deliver more than a 100 kV kick at 7 kW was fabricated. The RF performance of cavity such as the harmonic resonant frequencies, kick profiles, it’s stability, and electric center is tested at bench. The cavity will eventually be tested with a beam at Upgraded Injector Test Facility (UITF) in Jefferson Lab. In this paper, we report some features of fabrication and bench test results. We also briefly describe our beam test plan in the future. G.Park, H.Wang, R.A.Rimmer, S. Wang, and J.Guo, THP092, Proceedings of IPAC2018, Vancouver, Canada (2018). ** G.Park, et al, WEPRBO99, Proceedings of IPAC2019, Melbourne, Australia (2019).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST025
About •	Received ※ 11 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022
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WEPOPT028	Design Update on the HSR Injection Kicker for the EIC	1904
	M.P. Sangroula, C.J. Liaw, C. Liu, J. Sandberg, N. Tsoupas, B.P. Xiao BNL, Upton, New York, USA X. Sun ANL, Lemont, Illinois, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy The Electron-Ion Collider (EIC), the next-generation nuclear science facility, is under the design at the Brookhaven National Laboratory. The present RHIC rings will be reconfigured as the Hadron Storage Ring (HSR) for the EIC. Design of a stripline injection kicker for the HSR for beams with the rigidity of ∼ 81 T-m poses some technical challenges due to the expected shorter bunch spacing, heating due to higher peak current and the larger number of bunches, and the required higher pulsed voltage. Recently, we updated its mechanical design to optimize the characteristic and beam coupling impedances. In addition, we incorporated the impedance tuning capability by introducing the kicker aperture adjustment mechanism. Finally, we incorporated high voltage FID feedthroughs (FC26) to this kicker. This paper reports the design and optimization updates of the HSR injection kicker including the impedance tuning capability, optimization of both the characteristic and the beam coupling impedances, and finally the incorporation of a high voltage feedthrough design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT028
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 26 June 2022
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WEPOTK025	Concepts and Considerations for FCC-ee Top-Up Injection Strategies	2106
	R.L. Ramjiawan, W. Bartmann, Y. Dutheil, M. Hofer CERN, Meyrin, Switzerland M. Aiba PSI, Villigen PSI, Switzerland P.J. Hunchak University of Saskatchewan, Saskatoon, Canada P.J. Hunchak CLS, Saskatoon, Saskatchewan, Canada
	The Future Circular electron-positron Collider (FCC-ee) is proposed to operate in four modes, with beam energies from 45.6 GeV (Z-pole) to 182.5 GeV (tt-bar production) and luminosities up to 4.6×10³⁶ cm²s^-1. At the highest energies the beam lifetime would be less than one hour, meaning that top-up injection will be crucial to maximise the integrated luminosity. Two top-up injection strategies are considered here: conventional injection, employing a closed orbit bump and septum, and multipole-kicker injection, with a pulsed multipole magnet and septum. On-axis and off-axis injections are considered for both. We present a comparison of these injection strategies taking into account aspects such as spatial constraints, machine protection, disturbance to the stored beam and injection efficiency. We overview potential kicker and septum technologies for each.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK025
About •	Received ※ 03 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 14 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

WEPOST011

Studies on Top-Up Injection into the FCC-ee Collider Ring

1699

SUSPMF006

use link to see paper's listing under its alternate paper code

P.J. Hunchak, M.J. Boland
CLS, Saskatoon, Saskatchewan, Canada
M. Aiba
PSI, Villigen PSI, Switzerland
W. Bartmann, Y. Dutheil, M. Hofer, R.L. Ramjiawan, F. Zimmermann
CERN, Meyrin, Switzerland
M.J. Boland
University of Saskatchewan, Saskatoon, Canada

In order to maximize the luminosity production time in the FCC-ee, top-up injection will be employed. The positron and electron beams will be accelerated to the collision energy in the booster ring before being injected with either a small transverse or longitudinal separation to the stored beam. Using this scheme essentially keeps the beam current constant and, apart from a brief period during the injection process, collision data can be continuously acquired. Two top-up injection schemes, each with on- and off-momentum sub-schemes, viable for FCC-ee have been identified in the past and are studied in further detail to find a suitable design for each of the four operation modes of the FCC-ee. In this paper, injection straight optics, initial injection tracking studies and the effect on the stored beam are presented. Additionally, a basic proxy error lattice is introduced as a first step to studying injection into an imperfect machine.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST011

About •

Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022

Cite •

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

WEPOST013

Exploitation of Crystal Shadowing via Multi-Crystal Array, Optimisers and Reinforcement Learning

1707

F.M. Velotti, M. Di Castro, L.S. Esposito, M.A. Fraser, S.S. Gilardoni, B. Goddard, V. Kain, E. Matheson
CERN, Meyrin, Switzerland

The CERN Super Proton Synchrotron (SPS) routinely delivers proton and heavy ion beams to the North experimental Area (NA) in the form of 4.8 s spills. To produce such a long flux of particles, resonant third integer slow extraction is used, which, by design, foresees primary beam lost on the electrostatic septum wires to separate circulating from extracted beam. Shadowing with thin bent crystal has been proposed and successfully tested in the SPS, as detailed in *. In 2021, a thin crystal was used for physics production showing results compatible with what measured during early testing. In this paper, the results from the 2021 physics run are presented also comparing particle losses at extraction with previous operational years. The setting up of the crystal using numerical optimisers is detailed, with possible implementation of reinforcement learning (RL) agents to improve the setting up time. Finally, the full exploitation of crystal shadowing via multi-array crystals is discussed, together with the performance reach in the SPS.
F.Velotti, et. al, "Septum shadowing by means of a bent crystal to reduce slow extraction beam loss", Phys. Rev. Accel. Beams 22, 093502 - Published 27 September 2019

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST013

About •

Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 02 July 2022

Cite •

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

WEPOST025

A High Power Prototype of a Harmonic Kicker Cavity

1749

G.-T. Park, G.A. Grose, J. Guo, A. OBrien, R.A. Rimmer, H. Wang, R.S. Williams
JLab, Newport News, Virginia, USA
S.A. Overstreet
ODU, Norfolk, Virginia, USA

A harmonic kicker, a beam exchange device that can deflect the beam at an ultra-fast time scale (a few ns), has been developed in Jefferson Lab *, **. The high power prototype that can deliver more than a 100 kV kick at 7 kW was fabricated. The RF performance of cavity such as the harmonic resonant frequencies, kick profiles, it’s stability, and electric center is tested at bench. The cavity will eventually be tested with a beam at Upgraded Injector Test Facility (UITF) in Jefferson Lab. In this paper, we report some features of fabrication and bench test results. We also briefly describe our beam test plan in the future.
* G.Park, H.Wang, R.A.Rimmer, S. Wang, and J.Guo, THP092, Proceedings of IPAC2018, Vancouver, Canada (2018).
** G.Park, et al, WEPRBO99, Proceedings of IPAC2019, Melbourne, Australia (2019).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST025

About •

Received ※ 11 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022

Cite •

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

WEPOPT028

Design Update on the HSR Injection Kicker for the EIC

1904

M.P. Sangroula, C.J. Liaw, C. Liu, J. Sandberg, N. Tsoupas, B.P. Xiao
BNL, Upton, New York, USA
X. Sun
ANL, Lemont, Illinois, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
The Electron-Ion Collider (EIC), the next-generation nuclear science facility, is under the design at the Brookhaven National Laboratory. The present RHIC rings will be reconfigured as the Hadron Storage Ring (HSR) for the EIC. Design of a stripline injection kicker for the HSR for beams with the rigidity of ∼ 81 T-m poses some technical challenges due to the expected shorter bunch spacing, heating due to higher peak current and the larger number of bunches, and the required higher pulsed voltage. Recently, we updated its mechanical design to optimize the characteristic and beam coupling impedances. In addition, we incorporated the impedance tuning capability by introducing the kicker aperture adjustment mechanism. Finally, we incorporated high voltage FID feedthroughs (FC26) to this kicker. This paper reports the design and optimization updates of the HSR injection kicker including the impedance tuning capability, optimization of both the characteristic and the beam coupling impedances, and finally the incorporation of a high voltage feedthrough design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT028

About •

Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 26 June 2022

Cite •

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

WEPOTK025

Concepts and Considerations for FCC-ee Top-Up Injection Strategies

2106

R.L. Ramjiawan, W. Bartmann, Y. Dutheil, M. Hofer
CERN, Meyrin, Switzerland
M. Aiba
PSI, Villigen PSI, Switzerland
P.J. Hunchak
University of Saskatchewan, Saskatoon, Canada
P.J. Hunchak
CLS, Saskatoon, Saskatchewan, Canada

The Future Circular electron-positron Collider (FCC-ee) is proposed to operate in four modes, with beam energies from 45.6 GeV (Z-pole) to 182.5 GeV (tt-bar production) and luminosities up to 4.6×10³⁶ cm²s^-1. At the highest energies the beam lifetime would be less than one hour, meaning that top-up injection will be crucial to maximise the integrated luminosity. Two top-up injection strategies are considered here: conventional injection, employing a closed orbit bump and septum, and multipole-kicker injection, with a pulsed multipole magnet and septum. On-axis and off-axis injections are considered for both. We present a comparison of these injection strategies taking into account aspects such as spatial constraints, machine protection, disturbance to the stored beam and injection efficiency. We overview potential kicker and septum technologies for each.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK025

About •

Received ※ 03 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 14 June 2022

Cite •

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