IPAC2022 - List of Authors (Fraser, M.A.)

Paper	Title	Page
MOPOST006	Beam Commissioning and Optimisation in the CERN Proton Synchrotron After the Upgrade of the LHC Injectors	54
	A. Huschauer, M.R. Coly, D.G. Cotte, H. Damerau, M. Delrieux, J.-C. Dumont, Y. Dutheil, S.E.R. Easton, M.A. Fraser, O. Hans, G.I. Imesch, S. Joly, A. Lasheen, C.L. Lombard, R. Maillet, B. Mikulec, J.-M. Nonglaton, S. Sainz Perez, B. Salvant, R. Suykerbuyk, F. Tecker, R. Valera Teruel CERN, Meyrin, Switzerland
	The CERN LHC injector chain underwent a major upgrade during the Long Shutdown 2 (LS2) in the framework of the LHC Injectors Upgrade (LIU) project. After 2 years of installation work, the Proton Synchrotron (PS) was restarted in 2021 with the goal to achieve pre-LS2 beam quality by the end of 2021. This contribution details the main beam commissioning milestones, encountered difficulties and lessons learned. The status of the fixed-target and LHC beams will be given and improvements in terms of performance, controls and tools described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST006
About •	Received ※ 01 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 02 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOTK030	Beam Optics Modelling Through Fringe Fields During Injection and Extraction at the CERN Proton Synchrotron	511
	E.P. Johnson, M.G. Atanasov, Y. Dutheil, M.A. Fraser, E. Oponowicz CERN, Meyrin, Switzerland
	As the beam is injected and extracted from the CERN Proton Synchrotron, it passes through the fringing magnetic fields of the main bending units (MUs). In this study, tracking simulations using field maps created from a 3D magnetic model of the MUs are compared to beam based measurements made through the fast injection and slow extraction regions. The behaviour of the fringe field is characterised and its implementation in the MAD-X model of the machine is described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK030
About •	Received ※ 03 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 12 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOST041	Experience with Computer-Aided Optimizations in LINAC4 and PSB at CERN	945
	P.K. Skowroński, M.A. Fraser, I. Vojskovic CERN, Meyrin, Switzerland
	Accelerator optimization is routinely performed with the help of computer algorithms that fully automate these tasks. However, their efficiency, speed, and time to implement varies greatly depending on the algorithms used. In LINAC4 some of the automatic optimization routines were programmed using different algorithms to find the most suitable. We present the problems for which the computer algorithms were used and the results of our comparative study.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST041
About •	Received ※ 09 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 08 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOST045	Overview of the Machine Learning and Numerical Optimiser Applications on Beam Transfer Systems for LHC and Its Injectors	961
	F.M. Velotti, M.J. Barnes, E. Carlier, Y. Dutheil, M.A. Fraser, B. Goddard, N. Magnin, R.L. Ramjiawan, E. Renner, P. Van Trappen CERN, Meyrin, Switzerland E. Waagaard Uppsala University, Uppsala, Sweden
	Machine learning and numerical optimisation algorithms are getting more and more popular in the accelerator physics community and, thanks to the computing power available, their application in daily operation more likely. In the CERN accelerator complex, and specifically on the beam transfer systems, many promising exploitation of these numerical tools have been put in place in the last years. Some of the state-of-the-art machine learning models have been explored and used to solve problems that were never fully addressed in the past. In this paper, the most recent results of application of machine learning and numerical optimisation for injection, extraction and transfer of beam from machine and to experimental areas are presented. An overview of the possible next steps and shortcomings is finally discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST045
About •	Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 10 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEIYGD1	Achievements and Performance Prospects of the Upgraded LHC Injectors	1610
	V. Kain, S.C.P. Albright, R. Alemany-Fernández, M.E. Angoletta, F. Antoniou, T. Argyropoulos, F. Asvesta, B. Balhan, M.J. Barnes, D. Barrientos, H. Bartosik, P. Baudrenghien, G. Bellodi, N. Biancacci, A. Boccardi, J.C.C.M. Borburgh, C. Bracco, E. Carlier, D.G. Cotte, J. Coupard, H. Damerau, G.P. Di Giovanni, A. Findlay, M.A. Fraser, A. Funken, B. Goddard, G. Hagmann, K. Hanke, A. Huschauer, M. Jaussi, I. Karpov, T. Koevener, D. Küchler, J.-B. Lallement, A. Lasheen, T.E. Levens, K.S.B. Li, A.M. Lombardi, N. Madysa, E. Mahner, M. Meddahi, L. Mether, B. Mikulec, J.C. Molendijk, E. Montesinos, D. Nisbet, F.-X. Nuiry, G. Papotti, K. Paraschou, F. Pedrosa, T. Prebibaj, S. Prodon, D. Quartullo, E. Renner, F. Roncarolo, G. Rumolo, B. Salvant, M. Schenk, R. Scrivens, E.N. Shaposhnikova, P.K. Skowroński, A. Spierer, F. Tecker, D. Valuch, F.M. Velotti, R. Wegner, C. Zannini CERN, Meyrin, Switzerland
	To provide HL-LHC performance, the CERN LHC injector chain underwent a major upgrade during an almost 2-year-long shutdown. In the first half of 2021 the injectors were gradually re-started with the aim to reach at least pre-shutdown parameters for LHC as well as for fixed target beams. The strategy of the commissioning across the complex, a summary of the many challenges and finally the achievements will be presented. Several lessons were learned and have been integrated to define the strategy for the performance ramp-up over the coming years. Remaining limitations and prospects for LHC beam parameters at the exit of the LHC injector chain in the years to come will be discussed. Finally, the emerging need for improved operability of the CERN complex will be addressed, with a description of the first efforts to meet the availability and flexibility requirements of the HL-LHC era while at the same time maximizing fixed target physics output.
	Slides WEIYGD1 [5.905 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEIYGD1
About •	Received ※ 08 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 09 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOST012	Feasibility of Slow-Extracted High-Energy Ions From the CERN Proton Synchrotron for CHARM	1703
	M.A. Fraser, P.A. Arrutia Sota, K. Biłko, N. Charitonidis, S. Danzeca, M. Delrieux, M. Duraffourg, N. Emriskova, L.S. Esposito, R. García Alía, A. Guerrero, O. Hans, G.I. Imesch, E.P. Johnson, G. Lerner, I. Ortega Ruiz, G. Pezzullo, D. Prelipcean, F. Ravotti, F. Roncarolo, A. Waets CERN, Meyrin, Switzerland
	The CHARM High-energy Ions for Micro Electronics Reliability Assurance (CHIMERA) working group at CERN is investigating the feasibility of delivering high energy ion beams to the CHARM facility for the study of radiation effects to electronics components engineered to operate in harsh radiation environments, such as space or high-energy accelerators. The Proton Synchrotron has the potential of delivering the required high energy and high-Z (in this case, Pb) ions for radiation tests over the relevant range of Linear Energy Transfer of ~ 10 - 40 MeV cm²/mg with a > 1 mm penetration depth in silicon, specifically for single event effect tests. This contribution summarises the working group’s progress in demonstrating the feasibility of variable energy slow extraction and over a wide range of intensities. The results of a dedicated 6 GeV/u Pb ion beam test are reported to understand the performance limitations of the beam instrumentation systems needed to characterise the beam in CHARM.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST012
About •	Received ※ 02 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 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)

WEPOST015	Implementation of a Tune Sweep Slow Extraction with Constant Optics at MedAustron	1715
	P.A. Arrutia Sota, M.A. Fraser, B. Goddard, V. Kain, F.M. Velotti CERN, Meyrin, Switzerland P. Burrows JAI, Oxford, United Kingdom A. De Franco QST Rokkasho, Aomori, Japan F. Kuehteubl, M.T.F. Pivi, D.A. Prokopovich EBG MedAustron, Wr. Neustadt, Austria
	Conventional slow extraction driven by a tune sweep perturbs the optics and changes the presentation of the beam separatrix to the extraction septum during the spill. The constant optics slow extraction (COSE) technique, recently developed and deployed operationally at the CERN Super Proton Synchrotron to reduce beam loss on the extraction septum, was implemented at MedAustron to facilitate extraction with a tune sweep of operational beam quality. COSE fixes the optics of the extracted beam by scaling all machine settings with the beam rigidity following the extracted beam’s momentum. In this contribution the implementation of the COSE extraction technique is described before it is compared to the conventional tune sweep and operational betatron core driven cases using both simulations and recent measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST015
About •	Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 18 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOTK026	Commissioning of the ELENA Electrostatic Transfer Lines for the Antimatter Facility at CERN	2110
	Y. Dutheil, W. Bartmann, C. Carli, M.A. Fraser, D. Gamba, L. Ponce CERN, Meyrin, Switzerland
	ELENA is a small synchrotron ring that decelerates antiprotons down to a kinetic energy of 100 keV. With an experimental complex capable of housing up to 9 different experiments operating simultaneously, the transfer line design needed to be highly flexible. The low energy of the beam transported allowed the exploitation of electrostatic devices instead of magnets, to simplify design, production and operation. This contribution presents the systematic characterisation of the beam optics at the different experimental handover locations during beam commissioning using H⁻ ions from an external source, as well as the performance of the lines in operation with antiprotons. Finally, the effect of stray fields created by the experimental setup will be presented and compared with the first measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK026
About •	Received ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOTK028	Implementation of RF Channeling at the CERN PS for Spill Quality Improvements	2114
	P.A. Arrutia Sota, H. Damerau, M.A. Fraser, M. Vadai, F.M. Velotti CERN, Meyrin, Switzerland P. Burrows JAI, Oxford, United Kingdom
	Resonant slow extraction from synchrotrons aims at providing constant intensity spills over timescales much longer than the revolution period of the machine. However, the extracted intensity is undesirably modulated by noise on the machine’s power converters with a frequency range of between 50 Hz and a few kHz. The impact of power converter noise can be suppressed by exploiting a Radio Frequency (RF) technique known as empty bucket channelling, which increases the speed at which particles cross the tune resonance boundary. In this contribution the implementation of empty bucket channelling in the CERN Proton Synchrotron (PS) is described via simulation and measurement. The technique was tested with both a resonant RF cavity and an inductive Finemet cavity, which can produce non-sinusoidal waveforms, to significantly reduce the low frequency noise observed on the extracted spill.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK028
About •	Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 22 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOTK043	Matching Studies Between the CERN PSB and PS Using Turn-by-Turn Beam Profile Acquisitions with a Residual Beam Gas Ionisation Monitor	2161
	M.A. Fraser, M.R. Coly, A. Guerrero, A. Huschauer, S. Jensen, S. Levasseur, F. Roncarolo, A. Rossi, H.S. Sandberg, J.W. Storey CERN, Meyrin, Switzerland
	In the framework of the LHC Injectors Upgrade project, the Beam Gas Ionisation (BGI) profile monitors installed in the Proton Synchrotron (PS) were fitted with a gas injection system capable of boosting the signal rate high enough to capture single turn acquisitions immediately after injection. This contribution reports on the studies carried out during the beam commissioning of the BGI system in a turn-by-turn matching monitor mode for its eventual implementation in an optimisation framework to preserve emittance during transfer between the PS Booster and PS. The BGI commissioning included a benchmarking with data from a wire-grid secondary emission monitor inserted into the circulating beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK043
About •	Received ※ 02 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 30 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Beam Commissioning and Optimisation in the CERN Proton Synchrotron After the Upgrade of the LHC Injectors

54

A. Huschauer, M.R. Coly, D.G. Cotte, H. Damerau, M. Delrieux, J.-C. Dumont, Y. Dutheil, S.E.R. Easton, M.A. Fraser, O. Hans, G.I. Imesch, S. Joly, A. Lasheen, C.L. Lombard, R. Maillet, B. Mikulec, J.-M. Nonglaton, S. Sainz Perez, B. Salvant, R. Suykerbuyk, F. Tecker, R. Valera Teruel
CERN, Meyrin, Switzerland

The CERN LHC injector chain underwent a major upgrade during the Long Shutdown 2 (LS2) in the framework of the LHC Injectors Upgrade (LIU) project. After 2 years of installation work, the Proton Synchrotron (PS) was restarted in 2021 with the goal to achieve pre-LS2 beam quality by the end of 2021. This contribution details the main beam commissioning milestones, encountered difficulties and lessons learned. The status of the fixed-target and LHC beams will be given and improvements in terms of performance, controls and tools described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST006

About •

Received ※ 01 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 02 July 2022

Cite •

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

MOPOTK030

Beam Optics Modelling Through Fringe Fields During Injection and Extraction at the CERN Proton Synchrotron

511

E.P. Johnson, M.G. Atanasov, Y. Dutheil, M.A. Fraser, E. Oponowicz
CERN, Meyrin, Switzerland

As the beam is injected and extracted from the CERN Proton Synchrotron, it passes through the fringing magnetic fields of the main bending units (MUs). In this study, tracking simulations using field maps created from a 3D magnetic model of the MUs are compared to beam based measurements made through the fast injection and slow extraction regions. The behaviour of the fringe field is characterised and its implementation in the MAD-X model of the machine is described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK030

About •

Received ※ 03 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 12 June 2022

Cite •

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

TUPOST041

Experience with Computer-Aided Optimizations in LINAC4 and PSB at CERN

945

P.K. Skowroński, M.A. Fraser, I. Vojskovic
CERN, Meyrin, Switzerland

Accelerator optimization is routinely performed with the help of computer algorithms that fully automate these tasks. However, their efficiency, speed, and time to implement varies greatly depending on the algorithms used. In LINAC4 some of the automatic optimization routines were programmed using different algorithms to find the most suitable. We present the problems for which the computer algorithms were used and the results of our comparative study.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST041

About •

Received ※ 09 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 08 July 2022

Cite •

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

TUPOST045

Overview of the Machine Learning and Numerical Optimiser Applications on Beam Transfer Systems for LHC and Its Injectors

961

F.M. Velotti, M.J. Barnes, E. Carlier, Y. Dutheil, M.A. Fraser, B. Goddard, N. Magnin, R.L. Ramjiawan, E. Renner, P. Van Trappen
CERN, Meyrin, Switzerland
E. Waagaard
Uppsala University, Uppsala, Sweden

Machine learning and numerical optimisation algorithms are getting more and more popular in the accelerator physics community and, thanks to the computing power available, their application in daily operation more likely. In the CERN accelerator complex, and specifically on the beam transfer systems, many promising exploitation of these numerical tools have been put in place in the last years. Some of the state-of-the-art machine learning models have been explored and used to solve problems that were never fully addressed in the past. In this paper, the most recent results of application of machine learning and numerical optimisation for injection, extraction and transfer of beam from machine and to experimental areas are presented. An overview of the possible next steps and shortcomings is finally discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST045

About •

Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 10 July 2022

Cite •

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

WEIYGD1

Achievements and Performance Prospects of the Upgraded LHC Injectors

1610

V. Kain, S.C.P. Albright, R. Alemany-Fernández, M.E. Angoletta, F. Antoniou, T. Argyropoulos, F. Asvesta, B. Balhan, M.J. Barnes, D. Barrientos, H. Bartosik, P. Baudrenghien, G. Bellodi, N. Biancacci, A. Boccardi, J.C.C.M. Borburgh, C. Bracco, E. Carlier, D.G. Cotte, J. Coupard, H. Damerau, G.P. Di Giovanni, A. Findlay, M.A. Fraser, A. Funken, B. Goddard, G. Hagmann, K. Hanke, A. Huschauer, M. Jaussi, I. Karpov, T. Koevener, D. Küchler, J.-B. Lallement, A. Lasheen, T.E. Levens, K.S.B. Li, A.M. Lombardi, N. Madysa, E. Mahner, M. Meddahi, L. Mether, B. Mikulec, J.C. Molendijk, E. Montesinos, D. Nisbet, F.-X. Nuiry, G. Papotti, K. Paraschou, F. Pedrosa, T. Prebibaj, S. Prodon, D. Quartullo, E. Renner, F. Roncarolo, G. Rumolo, B. Salvant, M. Schenk, R. Scrivens, E.N. Shaposhnikova, P.K. Skowroński, A. Spierer, F. Tecker, D. Valuch, F.M. Velotti, R. Wegner, C. Zannini
CERN, Meyrin, Switzerland

To provide HL-LHC performance, the CERN LHC injector chain underwent a major upgrade during an almost 2-year-long shutdown. In the first half of 2021 the injectors were gradually re-started with the aim to reach at least pre-shutdown parameters for LHC as well as for fixed target beams. The strategy of the commissioning across the complex, a summary of the many challenges and finally the achievements will be presented. Several lessons were learned and have been integrated to define the strategy for the performance ramp-up over the coming years. Remaining limitations and prospects for LHC beam parameters at the exit of the LHC injector chain in the years to come will be discussed. Finally, the emerging need for improved operability of the CERN complex will be addressed, with a description of the first efforts to meet the availability and flexibility requirements of the HL-LHC era while at the same time maximizing fixed target physics output.

Slides WEIYGD1 [5.905 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEIYGD1

About •

Received ※ 08 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 09 July 2022

Cite •

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

WEPOST012

Feasibility of Slow-Extracted High-Energy Ions From the CERN Proton Synchrotron for CHARM

1703

M.A. Fraser, P.A. Arrutia Sota, K. Biłko, N. Charitonidis, S. Danzeca, M. Delrieux, M. Duraffourg, N. Emriskova, L.S. Esposito, R. García Alía, A. Guerrero, O. Hans, G.I. Imesch, E.P. Johnson, G. Lerner, I. Ortega Ruiz, G. Pezzullo, D. Prelipcean, F. Ravotti, F. Roncarolo, A. Waets
CERN, Meyrin, Switzerland

The CHARM High-energy Ions for Micro Electronics Reliability Assurance (CHIMERA) working group at CERN is investigating the feasibility of delivering high energy ion beams to the CHARM facility for the study of radiation effects to electronics components engineered to operate in harsh radiation environments, such as space or high-energy accelerators. The Proton Synchrotron has the potential of delivering the required high energy and high-Z (in this case, Pb) ions for radiation tests over the relevant range of Linear Energy Transfer of ~ 10 - 40 MeV cm²/mg with a > 1 mm penetration depth in silicon, specifically for single event effect tests. This contribution summarises the working group’s progress in demonstrating the feasibility of variable energy slow extraction and over a wide range of intensities. The results of a dedicated 6 GeV/u Pb ion beam test are reported to understand the performance limitations of the beam instrumentation systems needed to characterise the beam in CHARM.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST012

About •

Received ※ 02 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 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)

WEPOST015

Implementation of a Tune Sweep Slow Extraction with Constant Optics at MedAustron

1715

P.A. Arrutia Sota, M.A. Fraser, B. Goddard, V. Kain, F.M. Velotti
CERN, Meyrin, Switzerland
P. Burrows
JAI, Oxford, United Kingdom
A. De Franco
QST Rokkasho, Aomori, Japan
F. Kuehteubl, M.T.F. Pivi, D.A. Prokopovich
EBG MedAustron, Wr. Neustadt, Austria

Conventional slow extraction driven by a tune sweep perturbs the optics and changes the presentation of the beam separatrix to the extraction septum during the spill. The constant optics slow extraction (COSE) technique, recently developed and deployed operationally at the CERN Super Proton Synchrotron to reduce beam loss on the extraction septum, was implemented at MedAustron to facilitate extraction with a tune sweep of operational beam quality. COSE fixes the optics of the extracted beam by scaling all machine settings with the beam rigidity following the extracted beam’s momentum. In this contribution the implementation of the COSE extraction technique is described before it is compared to the conventional tune sweep and operational betatron core driven cases using both simulations and recent measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST015

About •

Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 18 June 2022

Cite •

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

WEPOTK026

Commissioning of the ELENA Electrostatic Transfer Lines for the Antimatter Facility at CERN

2110

Y. Dutheil, W. Bartmann, C. Carli, M.A. Fraser, D. Gamba, L. Ponce
CERN, Meyrin, Switzerland

ELENA is a small synchrotron ring that decelerates antiprotons down to a kinetic energy of 100 keV. With an experimental complex capable of housing up to 9 different experiments operating simultaneously, the transfer line design needed to be highly flexible. The low energy of the beam transported allowed the exploitation of electrostatic devices instead of magnets, to simplify design, production and operation. This contribution presents the systematic characterisation of the beam optics at the different experimental handover locations during beam commissioning using H⁻ ions from an external source, as well as the performance of the lines in operation with antiprotons. Finally, the effect of stray fields created by the experimental setup will be presented and compared with the first measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK026

About •

Received ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022

Cite •

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

WEPOTK028

Implementation of RF Channeling at the CERN PS for Spill Quality Improvements

2114

P.A. Arrutia Sota, H. Damerau, M.A. Fraser, M. Vadai, F.M. Velotti
CERN, Meyrin, Switzerland
P. Burrows
JAI, Oxford, United Kingdom

Resonant slow extraction from synchrotrons aims at providing constant intensity spills over timescales much longer than the revolution period of the machine. However, the extracted intensity is undesirably modulated by noise on the machine’s power converters with a frequency range of between 50 Hz and a few kHz. The impact of power converter noise can be suppressed by exploiting a Radio Frequency (RF) technique known as empty bucket channelling, which increases the speed at which particles cross the tune resonance boundary. In this contribution the implementation of empty bucket channelling in the CERN Proton Synchrotron (PS) is described via simulation and measurement. The technique was tested with both a resonant RF cavity and an inductive Finemet cavity, which can produce non-sinusoidal waveforms, to significantly reduce the low frequency noise observed on the extracted spill.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK028

About •

Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 22 June 2022

Cite •

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

WEPOTK043

Matching Studies Between the CERN PSB and PS Using Turn-by-Turn Beam Profile Acquisitions with a Residual Beam Gas Ionisation Monitor

2161

M.A. Fraser, M.R. Coly, A. Guerrero, A. Huschauer, S. Jensen, S. Levasseur, F. Roncarolo, A. Rossi, H.S. Sandberg, J.W. Storey
CERN, Meyrin, Switzerland

In the framework of the LHC Injectors Upgrade project, the Beam Gas Ionisation (BGI) profile monitors installed in the Proton Synchrotron (PS) were fitted with a gas injection system capable of boosting the signal rate high enough to capture single turn acquisitions immediately after injection. This contribution reports on the studies carried out during the beam commissioning of the BGI system in a turn-by-turn matching monitor mode for its eventual implementation in an optimisation framework to preserve emittance during transfer between the PS Booster and PS. The BGI commissioning included a benchmarking with data from a wire-grid secondary emission monitor inserted into the circulating beam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK043

About •

Received ※ 02 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 30 June 2022

Cite •

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