IPAC2022 - List of Authors (Hernalsteens, C.)

Paper	Title	Page
MOPOST027	The Zgoubidoo Python Framework for Ray-Tracing Simulations with Zgoubi: Applications to Fixed-Field Accelerators	118
SUSPMF043	use link to see paper's listing under its alternate paper code
	M. Vanwelde, E. Gnacadja, C. Hernalsteens, N. Pauly, E. Ramoisiaux, R. Tesse ULB, Bruxelles, Belgium C. Hernalsteens CERN, Meyrin, Switzerland
	The study of beam dynamics in accelerators featuring main magnets with complex geometries such as Fixed Field Accelerators (FFAs) requires simulation codes allowing step-by-step particle tracking in complex magnetic fields, such as the Zgoubi ray-tracing code. To facilitate the use of Zgoubi and to allow readily processing the resulting tracking data, we developed a modern Python 3 interface, Zgoubidoo, using Zgoubi in the backend. In this work, the key features of Zgoubidoo are illustrated by detailing the main steps to obtain a non-scaling FFA accelerator from a scaling design. The results obtained are in excellent agreement with prior results, including the tune computation and orbit shifts. These results are enhanced by Zgoubidoo beam dynamics analysis and visualization tools, including the placement of lattice elements in a global coordinate system and the computation of linear step-by-step optics. The validation of Zgoubidoo on conventional scaling and non-scaling FFA designs paves the way for future uses in innovative FFA design studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST027
About •	Received ※ 16 May 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOST033	Betatron Tune Characterization of the Rutgers 12-Inch Cyclotron for Different Magnetic Poles Configurations	136
	C. Hernalsteens CERN, Meyrin, Switzerland B.L. Beaudoin, T.W. Koeth UMD, College Park, Maryland, USA M. Miller Brown University, Providence, USA T.S. Ponter IBA, Louvain-la-Neuve, Belgium K.J. Ruisard ORNL, Oak Ridge, Tennessee, USA R. Tesse ULB, Bruxelles, Belgium
	The Rutgers cyclotron is a small 12-Inch, 1.2MeV proton cyclotron. Sets of magnet pole-tips were designed to demonstrate different cyclotron focusing options: weak focusing, radial sector focusing and spiral sector focusing. The purpose of this paper is to experimentally characterize the transverse dynamics provided by different types of focusing. Magnetic field measurements provide insight into the as-built properties of these magnetic poles configurations. First we discuss the axial betatron tune measurements as a function of the beam energy towards outer radii, which agree well with the values expected from measured magnetic data. Turn-by-turn betatron envelope oscillation measurements are also reported and compared with the tune measurements. Excellent agreement is once again found.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST033
About •	Received ※ 09 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 08 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOMS041	Concrete Shielding Activation for Proton Therapy Systems Using BDSIM and FISPACT-II	728
SUSPMF096	use link to see paper's listing under its alternate paper code
	E. Ramoisiaux, E. Gnacadja, C. Hernalsteens, N. Pauly, R. Tesse, M. Vanwelde ULB, Bruxelles, Belgium C. Hernalsteens CERN, Meyrin, Switzerland F. Stichelbaut IBA, Louvain-la-Neuve, Belgium
	Proton therapy systems are used worldwide for patient treatment and fundamental research. The generation of secondary particles when the beam interacts with the beamline elements is a well-known issue. In particular, the energy degrader is the dominant source of secondary radiation. This poses new challenges for the concrete shielding of compact systems and beamline elements activation computation. We use a novel methodology to seamlessly simulate all the processes relevant to the activation evaluation. A realistic model of the system is developed using Beam Delivery Simulation (BDSIM), a Geant4-based particle tracking code that allows a single model to simulate primary and secondary particle tracking and all particle-matter interactions. The secondary particle fluxes extracted from the simulations are provided as input to FISPACT-II to compute the activation by solving the rate equations. This approach is applied to the Ion Beam Applications (IBA) Proteus®ONE (P1) system and the shielding of the proton therapy research centre of Charleroi, Belgium. Proton loss distributions are used to model the production of secondary neutrals inside the accelerator structure. Two models for the distribution of proton losses are compared for the computation of the clearance index at specific locations of the design. Results show that the variation in the accelerator loss models can be characterised as a systematic error.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS041
About •	Received ※ 19 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 22 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOPT013	Effect of a Spurious CLIQ Firing on the Circulating Beam in HL-LHC	1862
	C. Hernalsteens, B. Lindström, E. Ravaioli, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann CERN, Meyrin, Switzerland
	The High Luminosity LHC (HL-LHC) will reach a nominal, levelled luminosity of §I{5e34}{\per\cm\square\per\second} and a stored energy of nearly §I{700}{MJ} in each of the two proton beams. The new large-aperture final focusing Nb₃Sn quadrupole magnets in IR1 and IR5, which are essential to achieve the luminosity target, will be protected using the novel Coupling Loss Induced Quench (CLIQ) system. A spurious discharge of a CLIQ unit will impact the circulating beam through higher order multipolar field components that develop rapidly over a few turns. This paper reports on dedicated beam tracking studies performed to evaluate the criticality of this failure on the HL-LHC beam. Simulations for different machine and optics configurations show that the beam losses reach a critical level after only five machine turns following the spurious CLIQ trigger, which is much faster than assumed in previous simulations that did not consider the higher order multipolar fields. Machine protection requirements using a dedicated interlock to mitigate this failure are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT013
About •	Received ※ 08 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 01 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPOPT014	The Effect of a Partially Depleted Halo on the Criticality and Detectability of Fast Failures in the HL-LHC	1866
	C. Hernalsteens, C. Lannoy, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann CERN, Meyrin, Switzerland
	In the High Luminosity LHC (HL-LHC) era, the bunch intensity will be increased to νm{2.2e11} protons, which is almost twice the nominal LHC intensity. The stored energy in each of the two beams will increase to §I{674}{MJ}. The HL-LHC will feature beams whose transverse halos are partially depleted by means of a hollow electron lens. The reduced stored energy in the beam tails will significantly change the development of losses caused by failures. This paper reports on beam tracking simulations evaluating the effect of a partially depleted halo on the criticality and detection of failures originating from the superconducting magnet protection systems. In addition, the effect of the transverse damper operating as a coherent excitation system leading to orbit excursions on a beam with a partially depleted halo is discussed. The results in terms of time-dependent beam losses are presented. The margins between the failure onset, its detection, and the time to reach critical loss levels, are discussed. The results are extrapolated to failure cases of different origins that induce similar beam loss dynamics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT014
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOMS003	Upgrade of a Proton Therapy Eye Treatment Nozzle Using a Cylindrical Beam Stopping Device for Enhanced Dose Rate Performances	2937
SUSPMF124	use link to see paper's listing under its alternate paper code
	E. Gnacadja, C. Hernalsteens, N. Pauly, E. Ramoisiaux, R. Tesse, M. Vanwelde ULB, Bruxelles, Belgium C. Hernalsteens CERN, Meyrin, Switzerland
	Proton therapy is a well established treatment method for ocular cancerous diseases. General-purpose multi-room systems which comprise eye-treatment beamlines must be thoroughly optimized to achieve the performances of fully dedicated systems in terms of depth-dose distal fall-off, lateral penumbra, and dose rate. For eye-treatment beamlines, the dose rate is one of the most critical clinical performances, as it directly defines the delivery time of a given treatment session. This delivery time must be kept as low as possible to reduce uncertainties due to undesired patient movement. We propose an alternative design of the Ion Beam Applications (IBA) Proteus Plus (P+) eye treatment beamline, which combines a beam-stopping device with the already existing scattering features of the beamline. The design is modelled with Beam Delivery SIMulation (BDSIM), a Geant4-based particle tracking and beam-matter interactions Monte-Carlo code, to demonstrate that it increases the maximum achievable dose rate by up to a factor §I{3} compared to the baseline configuration. An in-depth study of the system is performed and the resulting dosimetric properties are discussed in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS003
About •	Received ※ 20 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOMS004	Achromatic Gantry Design Using Fixed-Field Spiral Combined-Function Magnets	2941
	R. Tesse, E. Gnacadja, C. Hernalsteens, N. Pauly, E. Ramoisiaux, M. Vanwelde ULB, Bruxelles, Belgium C. Hernalsteens CERN, Meyrin, Switzerland
	Arc-therapy and flash therapy are promising proton therapy treatment modalities as they enable further sparing of the healthy tissues surrounding the tumor site. They impose strong constraints on the beam delivery system and rotating gantry structure, in particular in providing high dose rate and fast energy scanning. Fixed-field achromatic transport lattices potentially satisfy both constraints in allowing instant energy modulation and sufficient transmission efficiency while providing a compact footprint. The presented design study uses fixed-field magnets with spiral edges respecting the FFA scaling law. The cell structure and the layout are studied in simulation and integrated in a compact gantry. Results and further optimizations are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS004
About •	Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 26 June 2022 — Issue date ※ 11 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

MOPOST027

The Zgoubidoo Python Framework for Ray-Tracing Simulations with Zgoubi: Applications to Fixed-Field Accelerators

118

SUSPMF043

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

M. Vanwelde, E. Gnacadja, C. Hernalsteens, N. Pauly, E. Ramoisiaux, R. Tesse
ULB, Bruxelles, Belgium
C. Hernalsteens
CERN, Meyrin, Switzerland

The study of beam dynamics in accelerators featuring main magnets with complex geometries such as Fixed Field Accelerators (FFAs) requires simulation codes allowing step-by-step particle tracking in complex magnetic fields, such as the Zgoubi ray-tracing code. To facilitate the use of Zgoubi and to allow readily processing the resulting tracking data, we developed a modern Python 3 interface, Zgoubidoo, using Zgoubi in the backend. In this work, the key features of Zgoubidoo are illustrated by detailing the main steps to obtain a non-scaling FFA accelerator from a scaling design. The results obtained are in excellent agreement with prior results, including the tune computation and orbit shifts. These results are enhanced by Zgoubidoo beam dynamics analysis and visualization tools, including the placement of lattice elements in a global coordinate system and the computation of linear step-by-step optics. The validation of Zgoubidoo on conventional scaling and non-scaling FFA designs paves the way for future uses in innovative FFA design studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST027

About •

Received ※ 16 May 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022

Cite •

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

MOPOST033

Betatron Tune Characterization of the Rutgers 12-Inch Cyclotron for Different Magnetic Poles Configurations

136

C. Hernalsteens
CERN, Meyrin, Switzerland
B.L. Beaudoin, T.W. Koeth
UMD, College Park, Maryland, USA
M. Miller
Brown University, Providence, USA
T.S. Ponter
IBA, Louvain-la-Neuve, Belgium
K.J. Ruisard
ORNL, Oak Ridge, Tennessee, USA
R. Tesse
ULB, Bruxelles, Belgium

The Rutgers cyclotron is a small 12-Inch, 1.2MeV proton cyclotron. Sets of magnet pole-tips were designed to demonstrate different cyclotron focusing options: weak focusing, radial sector focusing and spiral sector focusing. The purpose of this paper is to experimentally characterize the transverse dynamics provided by different types of focusing. Magnetic field measurements provide insight into the as-built properties of these magnetic poles configurations. First we discuss the axial betatron tune measurements as a function of the beam energy towards outer radii, which agree well with the values expected from measured magnetic data. Turn-by-turn betatron envelope oscillation measurements are also reported and compared with the tune measurements. Excellent agreement is once again found.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST033

About •

Received ※ 09 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 08 July 2022

Cite •

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

MOPOMS041

Concrete Shielding Activation for Proton Therapy Systems Using BDSIM and FISPACT-II

728

SUSPMF096

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

E. Ramoisiaux, E. Gnacadja, C. Hernalsteens, N. Pauly, R. Tesse, M. Vanwelde
ULB, Bruxelles, Belgium
C. Hernalsteens
CERN, Meyrin, Switzerland
F. Stichelbaut
IBA, Louvain-la-Neuve, Belgium

Proton therapy systems are used worldwide for patient treatment and fundamental research. The generation of secondary particles when the beam interacts with the beamline elements is a well-known issue. In particular, the energy degrader is the dominant source of secondary radiation. This poses new challenges for the concrete shielding of compact systems and beamline elements activation computation. We use a novel methodology to seamlessly simulate all the processes relevant to the activation evaluation. A realistic model of the system is developed using Beam Delivery Simulation (BDSIM), a Geant4-based particle tracking code that allows a single model to simulate primary and secondary particle tracking and all particle-matter interactions. The secondary particle fluxes extracted from the simulations are provided as input to FISPACT-II to compute the activation by solving the rate equations. This approach is applied to the Ion Beam Applications (IBA) Proteus®ONE (P1) system and the shielding of the proton therapy research centre of Charleroi, Belgium. Proton loss distributions are used to model the production of secondary neutrals inside the accelerator structure. Two models for the distribution of proton losses are compared for the computation of the clearance index at specific locations of the design. Results show that the variation in the accelerator loss models can be characterised as a systematic error.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS041

About •

Received ※ 19 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 22 June 2022

Cite •

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

WEPOPT013

Effect of a Spurious CLIQ Firing on the Circulating Beam in HL-LHC

1862

C. Hernalsteens, B. Lindström, E. Ravaioli, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann
CERN, Meyrin, Switzerland

The High Luminosity LHC (HL-LHC) will reach a nominal, levelled luminosity of §I{5e34}{\per\cm\square\per\second} and a stored energy of nearly §I{700}{MJ} in each of the two proton beams. The new large-aperture final focusing Nb₃Sn quadrupole magnets in IR1 and IR5, which are essential to achieve the luminosity target, will be protected using the novel Coupling Loss Induced Quench (CLIQ) system. A spurious discharge of a CLIQ unit will impact the circulating beam through higher order multipolar field components that develop rapidly over a few turns. This paper reports on dedicated beam tracking studies performed to evaluate the criticality of this failure on the HL-LHC beam. Simulations for different machine and optics configurations show that the beam losses reach a critical level after only five machine turns following the spurious CLIQ trigger, which is much faster than assumed in previous simulations that did not consider the higher order multipolar fields. Machine protection requirements using a dedicated interlock to mitigate this failure are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT013

About •

Received ※ 08 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 01 July 2022

Cite •

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

WEPOPT014

The Effect of a Partially Depleted Halo on the Criticality and Detectability of Fast Failures in the HL-LHC

1866

C. Hernalsteens, C. Lannoy, O.K. Tuormaa, M. Villén Basco, C. Wiesner, D. Wollmann
CERN, Meyrin, Switzerland

In the High Luminosity LHC (HL-LHC) era, the bunch intensity will be increased to νm{2.2e11} protons, which is almost twice the nominal LHC intensity. The stored energy in each of the two beams will increase to §I{674}{MJ}. The HL-LHC will feature beams whose transverse halos are partially depleted by means of a hollow electron lens. The reduced stored energy in the beam tails will significantly change the development of losses caused by failures. This paper reports on beam tracking simulations evaluating the effect of a partially depleted halo on the criticality and detection of failures originating from the superconducting magnet protection systems. In addition, the effect of the transverse damper operating as a coherent excitation system leading to orbit excursions on a beam with a partially depleted halo is discussed. The results in terms of time-dependent beam losses are presented. The margins between the failure onset, its detection, and the time to reach critical loss levels, are discussed. The results are extrapolated to failure cases of different origins that induce similar beam loss dynamics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT014

About •

Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022

Cite •

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

THPOMS003

Upgrade of a Proton Therapy Eye Treatment Nozzle Using a Cylindrical Beam Stopping Device for Enhanced Dose Rate Performances

2937

SUSPMF124

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

E. Gnacadja, C. Hernalsteens, N. Pauly, E. Ramoisiaux, R. Tesse, M. Vanwelde
ULB, Bruxelles, Belgium
C. Hernalsteens
CERN, Meyrin, Switzerland

Proton therapy is a well established treatment method for ocular cancerous diseases. General-purpose multi-room systems which comprise eye-treatment beamlines must be thoroughly optimized to achieve the performances of fully dedicated systems in terms of depth-dose distal fall-off, lateral penumbra, and dose rate. For eye-treatment beamlines, the dose rate is one of the most critical clinical performances, as it directly defines the delivery time of a given treatment session. This delivery time must be kept as low as possible to reduce uncertainties due to undesired patient movement. We propose an alternative design of the Ion Beam Applications (IBA) Proteus Plus (P+) eye treatment beamline, which combines a beam-stopping device with the already existing scattering features of the beamline. The design is modelled with Beam Delivery SIMulation (BDSIM), a Geant4-based particle tracking and beam-matter interactions Monte-Carlo code, to demonstrate that it increases the maximum achievable dose rate by up to a factor §I{3} compared to the baseline configuration. An in-depth study of the system is performed and the resulting dosimetric properties are discussed in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS003

About •

Received ※ 20 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022

Cite •

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

THPOMS004

Achromatic Gantry Design Using Fixed-Field Spiral Combined-Function Magnets

2941

R. Tesse, E. Gnacadja, C. Hernalsteens, N. Pauly, E. Ramoisiaux, M. Vanwelde
ULB, Bruxelles, Belgium
C. Hernalsteens
CERN, Meyrin, Switzerland

Arc-therapy and flash therapy are promising proton therapy treatment modalities as they enable further sparing of the healthy tissues surrounding the tumor site. They impose strong constraints on the beam delivery system and rotating gantry structure, in particular in providing high dose rate and fast energy scanning. Fixed-field achromatic transport lattices potentially satisfy both constraints in allowing instant energy modulation and sufficient transmission efficiency while providing a compact footprint. The presented design study uses fixed-field magnets with spiral edges respecting the FFA scaling law. The cell structure and the layout are studied in simulation and integrated in a compact gantry. Results and further optimizations are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS004

About •

Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 26 June 2022 — Issue date ※ 11 July 2022

Cite •

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