HB2023 - List of Authors (Letchford, A.P.)

Paper	Title	Page
TUC2C1	Beam Physics Simulation Studies of 70 Mev ISIS Injector Linac	97
	S.A. Ahmadiannamin, H.V. Cavanagh, S.R. Lawrie, A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS neutron spallation source is a pioneering research infrastructure in the field of high intensity accelerator physics, catering to scientific users. Comprising a 70 MeV injector linac and an 800 MeV Rapid cycling synchrotron with two beam targets, this facility has witnessed significant upgrades in recent years, leading to enhanced transmission efficiency. Further optimization efforts are underway to ensure continuous improvement. This article focuses on beam physics simulation studies conducted on the current ISIS linac, aiming to gain a deeper understanding and analysis of various phenomena observed during routine operations and accelerator physics experimentation. By examining these phenomena, valuable insights can be obtained to inform the future development of high efficiency injector of ISIS-II.
	Slides TUC2C1 [6.467 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC2C1
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 13 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP01	ESS-Bilbao RFQ Power Coupler: Design, Simulations and Tests	433
	I. Bustinduy, A. Conde, D. Fernández-Cañoto, N. Garmendia, P.J. González, G. Harper, A. Kaftoosian, J. Martin, J.L. Muñoz ESS Bilbao, Zamudio, Spain A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	ESS-Bilbao RFQ power coupler is presented. The RFQ operates at 352.2 MHz and will accelerate the 32 mA proton beam extracted from the ion source up to 3.0MeV. The RFQ will complete the ESS-Bilbao injector, that can be used by the ARGITU neutron source or as a stand-alone facility. The machining of the RFQ is finished, and vacuum tests as well as low power RF measurements have been carried out. The presented power coupler is a first iteration of the device, designed to be of easier and faster manufacturing than what might be needed for future upgrades of the linac. The coupler does not have active cooling and no brazing has been needed to assemble it. It can operate at the RF power required by the RFQ but at lower duty cycles. The dielectric window is made of polymeric material, so it can withhold the assembly using vacuum seals and bolts. Design and manufacturing issues are reported in the paper, as well as the RF tests that have been carried out at medium power. Multipacting calculations compared to measured values during conditioning are also reported. High power tests of the coupler have also been performed in the ISIS-FETS RFQ and are also described here.
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP01
About •	Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 28 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP02	FFA Magnet for Pulsed High Power Proton Driver	436
	J.-B. Lagrange, C.W. Jolly, D.J. Kelliher, A.P. Letchford, S. Machida, I. Rodríguez, C.T. Rogers, J.D. Speed STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom S.J. Brooks BNL, Upton, New York, USA T.-J. Kuo Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Fixed Field Alternating gradient (FFA) accelerator is considered as a proton driver for the next generation spallation neutron source (ISIS-II). To demonstrate its suitability for high intensity operation, an FFA proton prototype ring is planned at RAL, called FETS-FFA. The main magnets are a critical part of the machine, and several characteristics of these magnets require attention, such as doublet spiral structure, essential operational flexibility in terms of machine optics and control of the fringe field extent from the nonlinear optics point of view. This paper will discuss the design of the prototype magnet for FETS-FFA ring.
	Poster THBP02 [5.871 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP02
About •	Received ※ 02 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 12 October 2023 — Issued ※ 23 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP08	Simulation Studies on the Low Energy Beam Transfer (LEBT) System of the ISIS Neutron Spallation Source	454
	S.A. Ahmadiannamin, D.C. Faircloth, S.R. Lawrie, A.P. Letchford, T.M. Sarmento, O.A. Tarvainen STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The transmission efficiency and beam dynamic parameters of the low-energy beam transfer (LEBT) section of proton accelerators, serving as a neutron spallation source, have a critical impact on beam loss in subsequent sections of the linear accelerator. Due to variations and mismatches, the beam parameters at the entrance of the radio-frequency quadrupole (RFQ) change, significantly affecting the transmission efficiency of the RFQ and the matching between RFQ and drift tube linac (DTL) structures. Recognizing the importance of this concept, particle-in-cell studies were conducted to optimize the LEBT section of the ISIS accelerator. This study presents the results of simulations.
	Poster THBP08 [1.081 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP08
About •	Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 30 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Beam Physics Simulation Studies of 70 Mev ISIS Injector Linac

97

S.A. Ahmadiannamin, H.V. Cavanagh, S.R. Lawrie, A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS neutron spallation source is a pioneering research infrastructure in the field of high intensity accelerator physics, catering to scientific users. Comprising a 70 MeV injector linac and an 800 MeV Rapid cycling synchrotron with two beam targets, this facility has witnessed significant upgrades in recent years, leading to enhanced transmission efficiency. Further optimization efforts are underway to ensure continuous improvement. This article focuses on beam physics simulation studies conducted on the current ISIS linac, aiming to gain a deeper understanding and analysis of various phenomena observed during routine operations and accelerator physics experimentation. By examining these phenomena, valuable insights can be obtained to inform the future development of high efficiency injector of ISIS-II.

Slides TUC2C1 [6.467 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC2C1

About •

Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 13 October 2023

Cite •

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

THBP01

ESS-Bilbao RFQ Power Coupler: Design, Simulations and Tests

433

I. Bustinduy, A. Conde, D. Fernández-Cañoto, N. Garmendia, P.J. González, G. Harper, A. Kaftoosian, J. Martin, J.L. Muñoz
ESS Bilbao, Zamudio, Spain
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

ESS-Bilbao RFQ power coupler is presented. The RFQ operates at 352.2 MHz and will accelerate the 32 mA proton beam extracted from the ion source up to 3.0MeV. The RFQ will complete the ESS-Bilbao injector, that can be used by the ARGITU neutron source or as a stand-alone facility. The machining of the RFQ is finished, and vacuum tests as well as low power RF measurements have been carried out. The presented power coupler is a first iteration of the device, designed to be of easier and faster manufacturing than what might be needed for future upgrades of the linac. The coupler does not have active cooling and no brazing has been needed to assemble it. It can operate at the RF power required by the RFQ but at lower duty cycles. The dielectric window is made of polymeric material, so it can withhold the assembly using vacuum seals and bolts. Design and manufacturing issues are reported in the paper, as well as the RF tests that have been carried out at medium power. Multipacting calculations compared to measured values during conditioning are also reported. High power tests of the coupler have also been performed in the ISIS-FETS RFQ and are also described here.

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP01

About •

Received ※ 29 September 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 28 October 2023

Cite •

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

THBP02

FFA Magnet for Pulsed High Power Proton Driver

436

J.-B. Lagrange, C.W. Jolly, D.J. Kelliher, A.P. Letchford, S. Machida, I. Rodríguez, C.T. Rogers, J.D. Speed
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
S.J. Brooks
BNL, Upton, New York, USA
T.-J. Kuo
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Fixed Field Alternating gradient (FFA) accelerator is considered as a proton driver for the next generation spallation neutron source (ISIS-II). To demonstrate its suitability for high intensity operation, an FFA proton prototype ring is planned at RAL, called FETS-FFA. The main magnets are a critical part of the machine, and several characteristics of these magnets require attention, such as doublet spiral structure, essential operational flexibility in terms of machine optics and control of the fringe field extent from the nonlinear optics point of view. This paper will discuss the design of the prototype magnet for FETS-FFA ring.

Poster THBP02 [5.871 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP02

About •

Received ※ 02 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 12 October 2023 — Issued ※ 23 October 2023

Cite •

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

THBP08

Simulation Studies on the Low Energy Beam Transfer (LEBT) System of the ISIS Neutron Spallation Source

454

S.A. Ahmadiannamin, D.C. Faircloth, S.R. Lawrie, A.P. Letchford, T.M. Sarmento, O.A. Tarvainen
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The transmission efficiency and beam dynamic parameters of the low-energy beam transfer (LEBT) section of proton accelerators, serving as a neutron spallation source, have a critical impact on beam loss in subsequent sections of the linear accelerator. Due to variations and mismatches, the beam parameters at the entrance of the radio-frequency quadrupole (RFQ) change, significantly affecting the transmission efficiency of the RFQ and the matching between RFQ and drift tube linac (DTL) structures. Recognizing the importance of this concept, particle-in-cell studies were conducted to optimize the LEBT section of the ISIS accelerator. This study presents the results of simulations.

Poster THBP08 [1.081 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP08

About •

Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 30 October 2023

Cite •

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