Publications by Suzie Sheehy


The effect of beam interruptions on the integrity of ADSR fuel pin cladding: A thermo-mechanical analysis

ANNALS OF NUCLEAR ENERGY 46 (2012) 97-105

A Ahmad, SL Sheehy, GT Parks


The Advantages and Challenges of Helical Coils for Small Accelerators-A Case Study

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 22 (2012) ARTN 4100110

H Witte, T Yokoi, SL Sheehy, K Peach, S Pattalwar, T Jones, J Strachan, N Bliss


A 1 gev cw ffag high intensity proton driver

IPAC 2012 - International Particle Accelerator Conference 2012 (2012) 3234-3236

SL Sheehy, C Johnstone

The drive for high beam power, high duty cycle, and reliable beams at reasonable cost has focused world attention on fixed-field accelerators, notably Fixed-Field Alternating Gradient accelerators (FFAGs). High-intensity GeV proton drivers are of particular interest, as these encounter duty cycle and space-charge limits in the synchrotron and machine size concerns in the weaker-focusing cyclotron. Recently, the concept of isochronous orbits has been explored and developed for non-scaling FFAGs using powerful new methodologies in FFAG accelerator design. These new breeds of FFAGs have been identified by international collaborations for serious study thanks to their potential applications including Accelerator Driven Subcritical Reactors (ADS) and Accelerator Transmutation of Waste. The extreme reliability requirements for ADS mandate CW operation capability and the FFAGs strong focusing, particularly in the vertical, will serve to mitigate the effect of space charge (as compared with the weak-focusing cyclotron). This paper reports on these new advances in FFAG accelerator technology and presents a stable, 0.25- 1GeV isochronous FFAG for an accelerator driven subcritical reactor. Copyright © 2012 by IEEE.


Acceleration in the linear non-scaling fixed-field alternating-gradient accelerator EMMA

NATURE PHYSICS 8 (2012) 243-247

S Machida, R Barlow, JS Berg, N Bliss, RK Buckley, JA Clarke, MK Craddock, R D'Arcy, R Edgecock, JM Garland, Y Giboudot, P Goudket, S Griffiths, C Hill, SF Hill, KM Hock, DJ Holder, MG Ibison, F Jackson, SP Jamison, C Johnstone, JK Jones, LB Jones, A Kalinin, E Keil, DJ Kelliher, IW Kirkman, S Koscielniak, K Marinov, N Marks, B Martlew, PA McIntosh, JW McKenzie, F Meot, KJ Middleman, A Moss, BD Muratori, J Orrett, HL Owen, J Pasternak, KJ Peach, MW Poole, Y-N Rao, Y Saveliev, DJ Scott, SL Sheehy, BJA Shepherd, R Smith, SL Smith, D Trbojevic, S Tzenov, T Weston, A Wheelhouse, PH Williams, A Wolski, T Yokoi


EFFECTS OF ALIGNMENT ERRORS IN PROTON NON-SCALING FFAG ACCELERATORS

INTERNATIONAL JOURNAL OF MODERN PHYSICS A 26 (2011) 1842-1851

SL Sheehy, DJ Kelliher


Space charge studies of a 1 gev isochronous non-scaling ffag proton driver

IPAC 2011 - 2nd International Particle Accelerator Conference (2011) 2715-2717

SL Sheehy

The production of very high power proton drivers in the 10 MW range is a considerable challenge to the accelerator community. Non-scaling FFAGs have gained interest in this field, as they may be able to provide smaller, cheaper accelerators than existing options. The recent development of an isochronous non-scaling FFAG is a promising advance, but must be shown to have stable beam dynamics in the presence of space charge. Simulations of this design are presented and the implications for future space charge studies discussed. Copyright © 2011 by IPAC'11/EPS-AG.


Dynamics of a novel isochronous non-scaling ffag

IPAC 2011 - 2nd International Particle Accelerator Conference (2011) 2712-2714

SL Sheehy

Many non-scaling FFAG accelerator designs involve magnetic fields that cannot be described in popular accelerator design codes, and complex beam dynamics that require extremely accurate simulations. A recent design of a 1 GeV isochronous non-scaling FFAG is used to compare the codes COSY Infinity and ZGOUBI, both of which are commonly used in FFAG design. Results are presented for the comparison of basic beam dynamics and calculated dynamic aperture. Copyright © 2011 by IPAC'11/EPS-AG.


The EMMA non-scaling FFAG

IPAC 2010 - 1st International Particle Accelerator Conference (2010) 4266-4268

R Edgecock, D Kelliher, S Machida, C Beard, N Bliss, J Clarke, S Griffiths, C Hill, S Jamison, J Jones, A Kalinin, K Marinov, N Marks, B Martlew, P McIntosh, B Muratori, J Orrett, Y Saveliev, B Shepherd, R Smith, S Smith, S Tzenov, A Wheelhouse, C White, JS Berg, M Craddock, S Koscielniak, J Crisp, C Johnstone, Y Giboudot, E Keil, F Méot, J Pasternak, S Sheehy, T Yokoi

The Electron Model for Many Applications (EMMA) will be the World's first non-scaling FFAG and is under construction at the STFC Daresbury Laboratory in the UK. Construction is due for completion in Summer 2010 and will be followed by commissioning with beam and a detailed experimental programme to study the functioning of this type of accelerator. This paper will give an overview of the motivation for the project and describe the EMMA design and hardware. The first results from commissioning will be presented in a separate paper.


Error study of a novel non-linear, nonscaling FFAG

IPAC 2010 - 1st International Particle Accelerator Conference (2010) 555-557

DJ Kelliher, S Machida, SL Sheehy

A novel nonlinear, nonscaling FFAG ring has been designed for proton and ion acceleration [1]. It can be used for proton and carbon therapy as well as a proton driver for various facilities such as a high intensity neutrino factory. The machine has novel features including variable energy extraction and a high repetition rate of about 1 kHz. Taking as an example the PAMELA proton ring, under study at the John Adams Institute in Oxford, we present results of an error study. A calculation of alignment tolerance is made, in which the effects of translational misalignments of the triplet magnets are included. The effect of misalignments on the dynamic aperture of the machine is investigated.


Engaging schools and the public with accelerator physics

IPAC 2010 - 1st International Particle Accelerator Conference (2010) 118-120

SL Sheehy

Accelerator physics is often viewed as a difficult subject to communicate to schools and the public. The Accelerate! project, initiated in the UK in 2008, engages audiences with accelerator physics through a 45-minute live, interactive demonstration show, using basic physics demonstrations to explain the science of particle accelerators and what they are used for. Feedback has been overwhelmingly positive from all areas and demand for the show is very high, with over 3000 students involved in the first year of running. The program is also contributing to the science communication skills of physics graduate students. I discuss how to portray basic accelerator concepts through easy to access demonstrations and initial results of audience evaluation of the show.


Orbit correction in a non-scaling FFAG

IPAC 2010 - 1st International Particle Accelerator Conference (2010) 4334-4336

DJ Kelliher, S Machida, SL Sheehy

EMMA - the Electron Model of Many Applications - is to be built at the STFC Daresbury Laboratory in the UK and will be the first non-scaling FFAG ever constructed. The purpose of EMMA is to study beam dynamics in such an accelerator. The EMMA orbit correction scheme must deal with two characteristics of a non-scaling FFAG: i.e. the lack of a well defined reference orbit and the variation with momentum of the phase advance. In this study we present a novel orbit correction scheme that avoids the former problem by instead aiming to maximise both the symmetry of the orbit and the physical aperture of the beam. The latter problem is dealt with by optimising the corrector strengths over the energy range.


Suppression of fusion by breakup: Resolving the discrepancy between the reactions of Be-9 with Pb-208 and Bi-209

PHYSICAL REVIEW C 81 (2010) ARTN 024608

M Dasgupta, DJ Hinde, SL Sheehy, B Bouriquet


EMMA-The world's first non-scaling FFAG

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 624 (2010) 1-19

R Barlow, JS Berg, C Beard, N Bliss, J Clarke, MK Craddock, J Crisp, R Edgecock, Y Giboudot, P Goudket, S Griffiths, C Hill, S Jamison, C Johnstone, A Kalinin, E Keil, D Kelliher, S Koscielniak, S Machida, K Marinov, N Marks, B Martlew, P McIntosh, F Meot, A Moss, B Muratori, H Owen, YN Rao, Y Saveliev, S Sheehy, B Shepherd, R Smith, S Smith, S Tzenov, A Wheelhouse, C White, T Yokoi


Fixed field alternating gradient accelerator with small orbit shift and tune excursion

PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS 13 (2010) ARTN 040101

SL Sheehy, KJ Peach, H Witte, DJ Kelliher, S Machida


PAMELA: Lattice solution for a medical C6+ therapy facility

IPAC 2010 - 1st International Particle Accelerator Conference (2010) 115-117

SL Sheehy, K Peach, H Witte, T Yokoi, DJ Kelliher, S Machida

PAMELA (Particle Accelerator for MEdicaL Applications) employs novel non-scaling Fixed Field Alternating Gradient (ns-FFAG) technology in the development of a proton and C6+ particle therapy facility. One of the challenges of this design is the acceleration of high energy C6+ in a lattice which enables high flexibility and reliability for treatments, yet remains minimal in size and complexity. Discussed here is the carbon 6+ lattice solution in terms of both design and performance.


The EMMA accelerator and implications for hadron non-scaling FFAGS

HB 2010 - 46th ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams (2010) 82-85

SL Sheehy

EMMA (Electron Model for Many Applications) is the worlds first non-scaling FFAG constructed at the Dares-bury Laboratory, UK. Commissioning activities have recently been undertaken and beam dynamics results relevant to hadron non-scaling FFAGs are presented. The impact of these results on the future design of non-scaling FFAGs for high intensity hadron beam applications is discussed.


Pamela overview and status

IPAC 2010 - 1st International Particle Accelerator Conference (2010) 112-114

K Peach, J Cobb, SL Sheehy, H Witte, T Yokoi, R Fenning, A Khan, R Seviour, C Johnstone, M Hill, B Jones, B Vojnovic, M Aslaninejad, M Easton, J Pasternak, JK Pozimski, C Beard, N Bliss, T Jones, P McIntosh, S Pattalwar, SL Smith, J Strachan, S Tzenov, TR Edgecock, ISK Gardner, D Kelliher, S Machida, RJ Barlow, H Owen, S Tygier

The status of PAMELA (Particle Accelerator for MEdical Applications) - an accelerator for proton and light ion therapy using a non-scaling FFAG (ns-FFAG) accelerator - is reviewed and discussed.


Pamela: Development of the RF system for a non-relativistic non-scaling FFAG

Proceedings of the 23rd Particle Accelerator Conference (2009)

T Yokoi, J Cobb, K Peach, S Sheehy, H Witte, M Aslaninejad, J Pasternak, J Pozimski, R Barlow, S Tygier, B Vojnovic, C Beard, P McIntosh, S Smith, R Fenning, I Gardner, D Kelliher, S Machida, R Seviour


Pamela: Development of the RF system for a non-scaling FFAG

23rd Particle Accelerator Conference (2009)

T Yokoi, K Cobb, K Peach, S Sheehy, H Witte, M Aslaninejad, J Pasternak, J Pozimski, R Barlow, S Tygier, B Vojnovic, C Beard, P McIntosh, S Smith, R Fenning, L Gardner, D Kelliher, S Machida, R Seviour


Beam acceleration studies of proton NS-FFAG

EPAC 2008 - Contributions to the Proceedings (2008) 3398-3400

T Yokoi, J Cobb, K Peach, S Sheehy

Resonance crossing during beam acceleration in a Non-Scaling FFAG could cause beam blow-up when the acceleration rate is slow. This could potentially constraint the lattice design of proton NS-FFAG. Therefore, an understanding of the beam dynamics of resonance crossing acceleration is crucially important to establish the design strategy of proton NS-FFAG. This paper describes the beam blowup process of an NS-FFAG and discuss the blow-up rate quantitatively.

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