IPAC2021 - List of Authors (Burrows, P.)

Paper	Title	Page
TUPAB019	A High-Resolution, Low-Latency, Bunch-by-Bunch Feedback System for Nano-Beam Stabilization	1378
	R.L. Ramjiawan, D.R. Bett, N. Blaskovic Kraljevic, T. Bromwich, P. Burrows, G.B. Christian, C. Perry JAI, Oxford, United Kingdom D.R. Bett CERN, Geneva, Switzerland N. Blaskovic Kraljevic ESS, Lund, Sweden G.B. Christian DLS, Oxfordshire, United Kingdom
	A low-latency, bunch-by-bunch feedback system employing high-resolution cavity Beam Position Monitors (BPMs) has been developed and tested at the Accelerator Test Facility (ATF2) at the High Energy Accelerator Research Organization (KEK), Japan. The feedback system was designed to demonstrate nanometer-level vertical stabilization at the focal point of the ATF2 and can be operated using either a single BPM to provide local beam stabilization, or by using two BPMs to stabilize the beam at an intermediate location. The feedback correction is implemented using a stripline kicker and the feedback calculations are performed on a digital board constructed around a Field Programmable Gate Array (FPGA). The feedback performance was tested with trains of two bunches, separated by 280ns, at a charge of ~1nC, where the vertical offset of the first bunch was measured and used to calculate the correction to be applied to the second bunch. The BPMs have been demonstrated to achieve an operational resolution of ~20nm. With the application of single-BPM and two-BPM feedback, beam stabilization of below 50nm and 41nm respectively has been achieved with a latency of 232ns.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB019
About •	paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 14 August 2021
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TUPAB020	A Sub-Micron Resolution, Bunch-by-Bunch Beam Trajectory Feedback System and Its Application to Reducing Wakefield Effects in Single-Pass Beamlines	1382
	D.R. Bett, P. Burrows, C. Perry, R.L. Ramjiawan JAI, Oxford, United Kingdom D.R. Bett CERN, Geneva, Switzerland K. Kubo, T. Okugi, N. Terunuma KEK, Ibaraki, Japan
	A high-precision intra-bunch-train beam orbit feedback correction system has been developed and tested at the KEK Accelerator Test Facility, ATF2. The system uses the vertical position of the bunch measured at two beam position monitors to calculate a pair of kicks which are applied to the next bunch using two upstream kickers, thereby correcting both the vertical position and trajectory angle. Using trains of two electron bunches separated in time by 187.6ns, the system was optimised so as to stabilize the beam offset at the feedback BPMs to better than 350nm, yielding a local trajectory angle correction to within 250nrad. The quality of the correction was verified using three downstream witness BPMs and the results were found to be in agreement with the predictions of a linear lattice model used to propagate the beam trajectory from the feedback region. This same model predicts a corrected be am jitter of c.1nm at the focal point of the accelerator. Measurements with a beam size monitor at this location demonstrate that reducing the trajectory jitter of the beam by a factor of 4 also reduces the increase in the measured beam size as a function of beam charge by a factor of ~1.6.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB020
About •	paper received ※ 13 May 2021 paper accepted ※ 01 July 2021 issue date ※ 11 August 2021
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WEPAB043	Consolidation and Future Upgrades to the CLEAR User Facility at CERN	2700
	L.A. Dyks, P. Korysko Oxford University, Physics Department, Oxford, Oxon, United Kingdom P. Burrows JAI, Oxford, United Kingdom R. Corsini, S. Curt, W. Farabolini, D. Gamba, L. Garolfi, A. Gilardi, E. Granados, G. McMonagle, H. Panuganti CERN, Meyrin, Switzerland W. Farabolini CEA-DRF-IRFU, France A. Gilardi University of Napoli Federico II, Napoli, Italy K.N. Sjobak University of Oslo, Oslo, Norway
	The CERN Linear Electron Accelerator for Research (CLEAR) at CERN has been operating since 2017 as a dedicated user facility providing beams for a varied range of experiments. CLEAR consists of a 20 m long linear accelerator (linac), able to produce beams from a Cs₂Te photocathode and accelerate them to energies of between 60 MeV and 220 MeV. Following the linac, an experimental beamline is located, in which irradiation tests, wakefield and impedances tudies, plasma lens experiments, beam diagnostics development, and terahertz (THz) emission studies, are performed. In this paper, we present recent upgrades to the entire beamline, as well as the design of future upgrades, such as a dogleg section connecting to an additional proposed experimental beamline. The gain in performance due to these upgrades is presented with a full range of available beam properties documented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB043
About •	paper received ※ 18 May 2021 paper accepted ※ 24 June 2021 issue date ※ 19 August 2021
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THPAB130	Design of a Very Low Energy Beamline for NA61/SHINE	4017
	C.A. Mussolini, N. Charitonidis CERN, Geneva, Switzerland P. Burrows JAI, Oxford, United Kingdom P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom Y. Nagai Colorado University at Boulder, Boulder, Colorado, USA Y. Nagai ELTE, Budapest, Hungary E.D. Zimmerman CIPS, Boulder, Colorado, USA
	A new, low-energy beamline branch is currently under consideration for the H₂ beamline at the CERN North Area. This new branch would extend the capabilities of the current infrastructure enabling the study of particles in the very low, 1-13 GeV/c, momentum range. The design of this new beamline involves various stages. Firstly, a study of the secondary targets to maximise the yield of secondary hadrons. Secondly, the development of high acceptance transverse optics with high momentum resolution on the order of a few %. Finally, we discuss the first considerations on instrumentation to enable particle identification and background rejection. The first experiment to profit from this new line could be NA61/SHINE, but other possible future fixed target experiments or test-beams installed in the downstream zones could also use the low-energy particles provided. The aim is to arrive at a complete design of this branch by the end of 2021, which, pending the approval of the CERN scientific committees, could be envisaged for construction after 2024. This timescale is compatible with requests for measurements by various large international collaborations, in the next 10-year horizon.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB130
About •	paper received ※ 15 May 2021 paper accepted ※ 27 July 2021 issue date ※ 27 August 2021
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Paper

Title

Page

A High-Resolution, Low-Latency, Bunch-by-Bunch Feedback System for Nano-Beam Stabilization

1378

R.L. Ramjiawan, D.R. Bett, N. Blaskovic Kraljevic, T. Bromwich, P. Burrows, G.B. Christian, C. Perry
JAI, Oxford, United Kingdom
D.R. Bett
CERN, Geneva, Switzerland
N. Blaskovic Kraljevic
ESS, Lund, Sweden
G.B. Christian
DLS, Oxfordshire, United Kingdom

A low-latency, bunch-by-bunch feedback system employing high-resolution cavity Beam Position Monitors (BPMs) has been developed and tested at the Accelerator Test Facility (ATF2) at the High Energy Accelerator Research Organization (KEK), Japan. The feedback system was designed to demonstrate nanometer-level vertical stabilization at the focal point of the ATF2 and can be operated using either a single BPM to provide local beam stabilization, or by using two BPMs to stabilize the beam at an intermediate location. The feedback correction is implemented using a stripline kicker and the feedback calculations are performed on a digital board constructed around a Field Programmable Gate Array (FPGA). The feedback performance was tested with trains of two bunches, separated by 280ns, at a charge of ~1nC, where the vertical offset of the first bunch was measured and used to calculate the correction to be applied to the second bunch. The BPMs have been demonstrated to achieve an operational resolution of ~20nm. With the application of single-BPM and two-BPM feedback, beam stabilization of below 50nm and 41nm respectively has been achieved with a latency of 232ns.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB019

About •

paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 14 August 2021

Export •

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

TUPAB020

A Sub-Micron Resolution, Bunch-by-Bunch Beam Trajectory Feedback System and Its Application to Reducing Wakefield Effects in Single-Pass Beamlines

1382

D.R. Bett, P. Burrows, C. Perry, R.L. Ramjiawan
JAI, Oxford, United Kingdom
D.R. Bett
CERN, Geneva, Switzerland
K. Kubo, T. Okugi, N. Terunuma
KEK, Ibaraki, Japan

A high-precision intra-bunch-train beam orbit feedback correction system has been developed and tested at the KEK Accelerator Test Facility, ATF2. The system uses the vertical position of the bunch measured at two beam position monitors to calculate a pair of kicks which are applied to the next bunch using two upstream kickers, thereby correcting both the vertical position and trajectory angle. Using trains of two electron bunches separated in time by 187.6ns, the system was optimised so as to stabilize the beam offset at the feedback BPMs to better than 350nm, yielding a local trajectory angle correction to within 250nrad. The quality of the correction was verified using three downstream witness BPMs and the results were found to be in agreement with the predictions of a linear lattice model used to propagate the beam trajectory from the feedback region. This same model predicts a corrected be am jitter of c.1nm at the focal point of the accelerator. Measurements with a beam size monitor at this location demonstrate that reducing the trajectory jitter of the beam by a factor of 4 also reduces the increase in the measured beam size as a function of beam charge by a factor of ~1.6.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB020

About •

paper received ※ 13 May 2021 paper accepted ※ 01 July 2021 issue date ※ 11 August 2021

Export •

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

WEPAB043

Consolidation and Future Upgrades to the CLEAR User Facility at CERN

2700

L.A. Dyks, P. Korysko
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
P. Burrows
JAI, Oxford, United Kingdom
R. Corsini, S. Curt, W. Farabolini, D. Gamba, L. Garolfi, A. Gilardi, E. Granados, G. McMonagle, H. Panuganti
CERN, Meyrin, Switzerland
W. Farabolini
CEA-DRF-IRFU, France
A. Gilardi
University of Napoli Federico II, Napoli, Italy
K.N. Sjobak
University of Oslo, Oslo, Norway

The CERN Linear Electron Accelerator for Research (CLEAR) at CERN has been operating since 2017 as a dedicated user facility providing beams for a varied range of experiments. CLEAR consists of a 20 m long linear accelerator (linac), able to produce beams from a Cs₂Te photocathode and accelerate them to energies of between 60 MeV and 220 MeV. Following the linac, an experimental beamline is located, in which irradiation tests, wakefield and impedances tudies, plasma lens experiments, beam diagnostics development, and terahertz (THz) emission studies, are performed. In this paper, we present recent upgrades to the entire beamline, as well as the design of future upgrades, such as a dogleg section connecting to an additional proposed experimental beamline. The gain in performance due to these upgrades is presented with a full range of available beam properties documented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB043

About •

paper received ※ 18 May 2021 paper accepted ※ 24 June 2021 issue date ※ 19 August 2021

Export •

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

THPAB130

Design of a Very Low Energy Beamline for NA61/SHINE

4017

C.A. Mussolini, N. Charitonidis
CERN, Geneva, Switzerland
P. Burrows
JAI, Oxford, United Kingdom
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
Y. Nagai
Colorado University at Boulder, Boulder, Colorado, USA
Y. Nagai
ELTE, Budapest, Hungary
E.D. Zimmerman
CIPS, Boulder, Colorado, USA

A new, low-energy beamline branch is currently under consideration for the H₂ beamline at the CERN North Area. This new branch would extend the capabilities of the current infrastructure enabling the study of particles in the very low, 1-13 GeV/c, momentum range. The design of this new beamline involves various stages. Firstly, a study of the secondary targets to maximise the yield of secondary hadrons. Secondly, the development of high acceptance transverse optics with high momentum resolution on the order of a few %. Finally, we discuss the first considerations on instrumentation to enable particle identification and background rejection. The first experiment to profit from this new line could be NA61/SHINE, but other possible future fixed target experiments or test-beams installed in the downstream zones could also use the low-energy particles provided. The aim is to arrive at a complete design of this branch by the end of 2021, which, pending the approval of the CERN scientific committees, could be envisaged for construction after 2024. This timescale is compatible with requests for measurements by various large international collaborations, in the next 10-year horizon.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB130

About •

paper received ※ 15 May 2021 paper accepted ※ 27 July 2021 issue date ※ 27 August 2021

Export •

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