IPAC2021 - List of Authors (Sheehy, S.L.)

Paper	Title	Page
MOPAB374	Creating Exact Multipolar Fields in Accelerating RF Cavities via an Azimuthally Modulated Design	1154
	L.M. Wroe, S.L. Sheehy JAI, Oxford, United Kingdom R. Apsimon Cockcroft Institute, Lancaster University, Lancaster, United Kingdom M. Dosanjh CERN, Meyrin, Switzerland S.L. Sheehy The University of Melbourne, Melbourne, Victoria, Australia
	In this paper, we present a novel method for designing RF structures with specifically tailored multipolar field contributions. This has a range of applications, including the suppression of unwanted multipolar fields or the introduction of wanted terms, such as for quadrupole focusing. In this article, we outline the general design methodology and compare the expected results to 3D CST simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB374
About •	paper received ※ 19 May 2021 paper accepted ※ 08 June 2021 issue date ※ 23 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB236	First Order Analytic Approaches to Modelling the Vertical Excursion Fixed Field Alternating Gradient Accelerator	4262
	M.E. Topp-Mugglestone, S.L. Sheehy JAI, Oxford, United Kingdom J.-B. Lagrange, S. Machida STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	Whilst the Vertical Excursion Fixed Field Alternating Gradient Accelerator (VFFA) remains a promising solution to a number of problems at the frontiers of accelerator physics, the optics of this type of machine are still poorly understood. Current designers are forced to rely on brute-force numerical tracking codes, with optimisation dependent on time-consuming parameter scans. With an aim to both improve understanding of this machine, as well as to develop tools for rapid design and optimisation of VFFA lattices, first steps towards an analytic approach based on a linearised Hamiltonian formalism have been developed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB236
About •	paper received ※ 13 May 2021 paper accepted ※ 14 July 2021 issue date ※ 10 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPAB234	Exploring Accelerators for Intense Beams with the IBEX Paul Trap	1980
	J.A.D. Flowerdew University of Oxford, Oxford, United Kingdom D.J. Kelliher, S. Machida STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	Accelerators built from linear components will exhibit bounded and stable particle motion in the ideal case. However, any imperfections in field strength or misalignment of components can introduce chaotic and unstable particle motion. All accelerators are prone to such non-linearities but the effects are even more significant in high intensity particle beams with the presence of space charge effects. This work aims to explore the non-linearities which arise in high intensity particle beams using the scaled experiment, IBEX. The IBEX experiment is a linear Paul trap that allows the transverse dynamics of a collection of trapped particles to be studied by mimicking the propagation through multiple quadrupole lattice periods whilst remaining stationary in the laboratory frame. IBEX is currently undergoing a non-linear upgrade with the goal of investigating Non-linear Integrable Optics (NIO) in order to improve our understanding and utilisation of high intensity particle beams.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB234
About •	paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 12 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB182	Automated Synchrotron Lattice Design and Optimisation Using a Multi-Objective Genetic Algorithm	616
	X. Zhang, S.L. Sheehy The University of Melbourne, Melbourne, Victoria, Australia E. Benedetto TERA, Novara, Italy E. Benedetto CERN, Meyrin, Switzerland
	Funding: This work is partially supported by the Australian Government Research Training Program Scholarship. As part of the Next Ion Medical Machine Study (NIMMS), we present a new method for designing synchrotron lattices. A step-wise approach was used to generate random lattice structures from a set of feedforward neural networks. These lattice designs are optimised by evolving the networks over many iterations with a multi-objective genetic algorithm (MOGA). The final set of solutions represent the most effi- cient and feasible lattices which satisfy the design constraints. It is up to the lattice designer to choose a design that best suits the intended application. The automated algorithm presented here randomly samples from all possible lattice layouts and reaches the global optimum over many iterations. The requirements of an efficient extraction scheme in hadron therapy synchrotrons impose stringent constraints on the lat- tice optical functions. Using this algorithm allows us to find the global optimum that is tailored to these constraints and to fully utilise the flexibilities provided by new technology.
	Poster MOPAB182 [6.006 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB182
About •	paper received ※ 15 May 2021 paper accepted ※ 23 June 2021 issue date ※ 14 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB415	Failure Rates and Downtimes of Multi-Leaf Collimators in Indonesia	1248
	G.S. Peiris, S.L. Sheehy The University of Melbourne, Melbourne, Victoria, Australia M.F. Kasim, S.A. Pawiro University of Indonesia, Depok, Jawa Barat, Indonesia
	One of the greatest barriers to cancer treatment in Low and Middle-Income Countries (LMICs) is the access to Radiotherapy Linear Accelerators (LINACs). Not only are the LINACs complex, the harsh environment of LMICs cause frequent breakdowns resulting in downtimes ranging from days to months. Recent research has identified a disparity between LMICs and High Income Countries (HICs) and determined the Multi-Leaf Collimator (MLC) as a component needing re-evaluation. The MLC causes over 30% of the problems in RT LINACs, but the modes of failure and quantify the extent of the damage done are yet to be quantified. Using data from across Indonesia, we show the pathways to failure of RT Machines and frequency of breakdowns over time. A component of the MLC needs to be replaced every 9.98 faults per 1000 patients treated and the MLC itself breaks down on average every 36±1.8 days. When comparing the downtime by leaf width, the data shows 5mm leaves contribute 18.27±6.5% to all breakdowns while 10mm makes up 15.87±4.3%. These results outline the need to reassess the current generation of RT LINACs and ultimately work towards guiding future designs to be robust enough for all environments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB415
About •	paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 16 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB417	Preliminary Study of a Large Energy Acceptance FFA Beam Delivery System for Particle Therapy	1256
	J.S.L. Yap, E.R. Higgins, S.L. Sheehy The University of Melbourne, Melbourne, Victoria, Australia
	The availability and use of ion beams for radiotherapy has grown significantly, led by technological developments to exploit the dosimetric advantages offered by charged particles. The benefits of particle therapy (PT) are well identified however its utilisation is still limited by high facility costs and technological challenges. A possibility to address both of these can be considered by improvements to the beam delivery system (BDS). Existing beamlines and gantries transport beams with a momentum range of ±1% and consequently, adjustments in depth or beam energy require all the magnetic fields to be changed. The speed to switch energies is a limiting constraint of the BDS and a determinant of the overall treatment time. A novel concept using fixed field alternating gradient (FFA) optics enables a large energy acceptance (LEA) as beams of varying energies can traverse the beamline at multiple physical positions given the same magnetic field. This presents the potential to provide faster, higher quality treatments at lower costs, with the capability to deliver advanced PT techniques such as multi-ion therapy. We explore the applicability and benefits of a LEA BDS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB417
About •	paper received ※ 18 May 2021 paper accepted ※ 27 July 2021 issue date ※ 15 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPAB402	Review of Technologies for Ion Therapy Accelerators	2465
	H.X.Q. Norman, R.B. Appleby, A.F. Steinberg UMAN, Manchester, United Kingdom E. Benedetto TERA, Novara, Italy E. Benedetto, M. Sapinski CERN, Meyrin, Switzerland H.L. Owen STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom H.L. Owen Cockcroft Institute, Warrington, Cheshire, United Kingdom M. Sapinski GSI, Darmstadt, Germany S.L. Sheehy The University of Melbourne, Melbourne, Victoria, Australia
	Cancer therapy using protons and heavier ions such as carbon has demonstrated advantages over other radiotherapy treatments. To bring about the next generation of clinical facilities, the requirements are likely to reduce the footprint, obtain beam intensities above 1E10 particles per spill, and achieve faster extraction for more rapid, flexible treatment. This review follows the technical development of ion therapy, discussing how machine parameters have evolved, as well as trends emerging in technologies for novel treatments such as FLASH. To conclude, the future prospects of ion therapy accelerators are evaluated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB402
About •	paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 24 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB374	The Southern Hemisphere’s First X-Band Radio-Frequency Test Facility at the University of Melbourne	3588
	M. Volpi, R.P. Rassool, S.L. Sheehy, G. Taylor, S.D. Williams The University of Melbourne, Melbourne, Victoria, Australia M.J. Boland CLS, Saskatoon, Saskatchewan, Canada M.J. Boland University of Saskatchewan, Saskatoon, Canada N. Catalán Lasheras, S. Gonzalez Anton, G. McMonagle, S. Stapnes, W. Wuensch CERN, Meyrin, Switzerland R.T. Dowd, K. Zingre AS - ANSTO, Clayton, Australia
	The first Southern Hemisphere X-band Laboratory for Accelerators and Beams (X-LAB) is under construction at the University of Melbourne, and it will operate CERN X-band test stand containing two 12GHz 6MW klystron amplifiers. By power combination through hybrid couplers and the use of pulse compressors, up to 50 MW of peak power can be sent to any of 2 test slots at pulse repetition rates up to 400 Hz. The test stand is dedicated to RF conditioning and testing CLIC’s high gradient accelerating structures beyond 100 MV/m. It will also form the basis for developing a compact accelerator for medical applications, such as radiotherapy and compact light sources. Australian researchers working as part of a collaboration between the University of Melbourne, international universities, national industries, the Australian Synchrotron -ANSTO, Canadian Light Source and the CERN believe that creating a laboratory for novel accelerator research in Australia could drive technological and medical innovation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB374
About •	paper received ※ 18 May 2021 paper accepted ※ 06 July 2021 issue date ※ 30 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Creating Exact Multipolar Fields in Accelerating RF Cavities via an Azimuthally Modulated Design

1154

L.M. Wroe, S.L. Sheehy
JAI, Oxford, United Kingdom
R. Apsimon
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
M. Dosanjh
CERN, Meyrin, Switzerland
S.L. Sheehy
The University of Melbourne, Melbourne, Victoria, Australia

In this paper, we present a novel method for designing RF structures with specifically tailored multipolar field contributions. This has a range of applications, including the suppression of unwanted multipolar fields or the introduction of wanted terms, such as for quadrupole focusing. In this article, we outline the general design methodology and compare the expected results to 3D CST simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB374

About •

paper received ※ 19 May 2021 paper accepted ※ 08 June 2021 issue date ※ 23 August 2021

Export •

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

THPAB236

First Order Analytic Approaches to Modelling the Vertical Excursion Fixed Field Alternating Gradient Accelerator

4262

M.E. Topp-Mugglestone, S.L. Sheehy
JAI, Oxford, United Kingdom
J.-B. Lagrange, S. Machida
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

Whilst the Vertical Excursion Fixed Field Alternating Gradient Accelerator (VFFA) remains a promising solution to a number of problems at the frontiers of accelerator physics, the optics of this type of machine are still poorly understood. Current designers are forced to rely on brute-force numerical tracking codes, with optimisation dependent on time-consuming parameter scans. With an aim to both improve understanding of this machine, as well as to develop tools for rapid design and optimisation of VFFA lattices, first steps towards an analytic approach based on a linearised Hamiltonian formalism have been developed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB236

About •

paper received ※ 13 May 2021 paper accepted ※ 14 July 2021 issue date ※ 10 August 2021

Export •

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

TUPAB234

Exploring Accelerators for Intense Beams with the IBEX Paul Trap

1980

J.A.D. Flowerdew
University of Oxford, Oxford, United Kingdom
D.J. Kelliher, S. Machida
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

Accelerators built from linear components will exhibit bounded and stable particle motion in the ideal case. However, any imperfections in field strength or misalignment of components can introduce chaotic and unstable particle motion. All accelerators are prone to such non-linearities but the effects are even more significant in high intensity particle beams with the presence of space charge effects. This work aims to explore the non-linearities which arise in high intensity particle beams using the scaled experiment, IBEX. The IBEX experiment is a linear Paul trap that allows the transverse dynamics of a collection of trapped particles to be studied by mimicking the propagation through multiple quadrupole lattice periods whilst remaining stationary in the laboratory frame. IBEX is currently undergoing a non-linear upgrade with the goal of investigating Non-linear Integrable Optics (NIO) in order to improve our understanding and utilisation of high intensity particle beams.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB234

About •

paper received ※ 19 May 2021 paper accepted ※ 18 June 2021 issue date ※ 12 August 2021

Export •

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

MOPAB182

Automated Synchrotron Lattice Design and Optimisation Using a Multi-Objective Genetic Algorithm

616

X. Zhang, S.L. Sheehy
The University of Melbourne, Melbourne, Victoria, Australia
E. Benedetto
TERA, Novara, Italy
E. Benedetto
CERN, Meyrin, Switzerland

Funding: This work is partially supported by the Australian Government Research Training Program Scholarship.
As part of the Next Ion Medical Machine Study (NIMMS), we present a new method for designing synchrotron lattices. A step-wise approach was used to generate random lattice structures from a set of feedforward neural networks. These lattice designs are optimised by evolving the networks over many iterations with a multi-objective genetic algorithm (MOGA). The final set of solutions represent the most effi- cient and feasible lattices which satisfy the design constraints. It is up to the lattice designer to choose a design that best suits the intended application. The automated algorithm presented here randomly samples from all possible lattice layouts and reaches the global optimum over many iterations. The requirements of an efficient extraction scheme in hadron therapy synchrotrons impose stringent constraints on the lat- tice optical functions. Using this algorithm allows us to find the global optimum that is tailored to these constraints and to fully utilise the flexibilities provided by new technology.

Poster MOPAB182 [6.006 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB182

About •

paper received ※ 15 May 2021 paper accepted ※ 23 June 2021 issue date ※ 14 August 2021

Export •

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

MOPAB415

Failure Rates and Downtimes of Multi-Leaf Collimators in Indonesia

1248

G.S. Peiris, S.L. Sheehy
The University of Melbourne, Melbourne, Victoria, Australia
M.F. Kasim, S.A. Pawiro
University of Indonesia, Depok, Jawa Barat, Indonesia

One of the greatest barriers to cancer treatment in Low and Middle-Income Countries (LMICs) is the access to Radiotherapy Linear Accelerators (LINACs). Not only are the LINACs complex, the harsh environment of LMICs cause frequent breakdowns resulting in downtimes ranging from days to months. Recent research has identified a disparity between LMICs and High Income Countries (HICs) and determined the Multi-Leaf Collimator (MLC) as a component needing re-evaluation. The MLC causes over 30% of the problems in RT LINACs, but the modes of failure and quantify the extent of the damage done are yet to be quantified. Using data from across Indonesia, we show the pathways to failure of RT Machines and frequency of breakdowns over time. A component of the MLC needs to be replaced every 9.98 faults per 1000 patients treated and the MLC itself breaks down on average every 36±1.8 days. When comparing the downtime by leaf width, the data shows 5mm leaves contribute 18.27±6.5% to all breakdowns while 10mm makes up 15.87±4.3%. These results outline the need to reassess the current generation of RT LINACs and ultimately work towards guiding future designs to be robust enough for all environments.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB415

About •

paper received ※ 19 May 2021 paper accepted ※ 09 June 2021 issue date ※ 16 August 2021

Export •

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

MOPAB417

Preliminary Study of a Large Energy Acceptance FFA Beam Delivery System for Particle Therapy

1256

J.S.L. Yap, E.R. Higgins, S.L. Sheehy
The University of Melbourne, Melbourne, Victoria, Australia

The availability and use of ion beams for radiotherapy has grown significantly, led by technological developments to exploit the dosimetric advantages offered by charged particles. The benefits of particle therapy (PT) are well identified however its utilisation is still limited by high facility costs and technological challenges. A possibility to address both of these can be considered by improvements to the beam delivery system (BDS). Existing beamlines and gantries transport beams with a momentum range of ±1% and consequently, adjustments in depth or beam energy require all the magnetic fields to be changed. The speed to switch energies is a limiting constraint of the BDS and a determinant of the overall treatment time. A novel concept using fixed field alternating gradient (FFA) optics enables a large energy acceptance (LEA) as beams of varying energies can traverse the beamline at multiple physical positions given the same magnetic field. This presents the potential to provide faster, higher quality treatments at lower costs, with the capability to deliver advanced PT techniques such as multi-ion therapy. We explore the applicability and benefits of a LEA BDS.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB417

About •

paper received ※ 18 May 2021 paper accepted ※ 27 July 2021 issue date ※ 15 August 2021

Export •

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

TUPAB402

Review of Technologies for Ion Therapy Accelerators

2465

H.X.Q. Norman, R.B. Appleby, A.F. Steinberg
UMAN, Manchester, United Kingdom
E. Benedetto
TERA, Novara, Italy
E. Benedetto, M. Sapinski
CERN, Meyrin, Switzerland
H.L. Owen
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H.L. Owen
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M. Sapinski
GSI, Darmstadt, Germany
S.L. Sheehy
The University of Melbourne, Melbourne, Victoria, Australia

Cancer therapy using protons and heavier ions such as carbon has demonstrated advantages over other radiotherapy treatments. To bring about the next generation of clinical facilities, the requirements are likely to reduce the footprint, obtain beam intensities above 1E10 particles per spill, and achieve faster extraction for more rapid, flexible treatment. This review follows the technical development of ion therapy, discussing how machine parameters have evolved, as well as trends emerging in technologies for novel treatments such as FLASH. To conclude, the future prospects of ion therapy accelerators are evaluated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB402

About •

paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 24 August 2021

Export •

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

WEPAB374

The Southern Hemisphere’s First X-Band Radio-Frequency Test Facility at the University of Melbourne

3588

M. Volpi, R.P. Rassool, S.L. Sheehy, G. Taylor, S.D. Williams
The University of Melbourne, Melbourne, Victoria, Australia
M.J. Boland
CLS, Saskatoon, Saskatchewan, Canada
M.J. Boland
University of Saskatchewan, Saskatoon, Canada
N. Catalán Lasheras, S. Gonzalez Anton, G. McMonagle, S. Stapnes, W. Wuensch
CERN, Meyrin, Switzerland
R.T. Dowd, K. Zingre
AS - ANSTO, Clayton, Australia

The first Southern Hemisphere X-band Laboratory for Accelerators and Beams (X-LAB) is under construction at the University of Melbourne, and it will operate CERN X-band test stand containing two 12GHz 6MW klystron amplifiers. By power combination through hybrid couplers and the use of pulse compressors, up to 50 MW of peak power can be sent to any of 2 test slots at pulse repetition rates up to 400 Hz. The test stand is dedicated to RF conditioning and testing CLIC’s high gradient accelerating structures beyond 100 MV/m. It will also form the basis for developing a compact accelerator for medical applications, such as radiotherapy and compact light sources. Australian researchers working as part of a collaboration between the University of Melbourne, international universities, national industries, the Australian Synchrotron -ANSTO, Canadian Light Source and the CERN believe that creating a laboratory for novel accelerator research in Australia could drive technological and medical innovation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB374

About •

paper received ※ 18 May 2021 paper accepted ※ 06 July 2021 issue date ※ 30 August 2021

Export •

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