Hywel Owen

Hywel Owen
Science and Technology Facilities Council | STFC · Accelerator Science and Technology Centre (ASTeC)

PhD
Group Leader for the Accelerator Physics Group at UKRI-STFC Daresbury Laboratory. Working primarily on light sources.

About

158
Publications
24,597
Reads
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1,561
Citations
Additional affiliations
September 2008 - present
The University of Manchester
Position
  • Lecturer in Accelerator Physics
December 1999 - December 1999
CERN
Position
  • Visiting scientist
September 1994 - August 2008
Science and Technology Facilities Council
Position
  • Senior Accelerator Physicist
Education
October 1991 - October 1994
The University of Manchester
Field of study
  • Physics
October 1988 - October 1991
The University of Manchester
Field of study
  • Physics

Publications

Publications (158)
Article
Full-text available
The materials engineering database relevant to fusion irradiation is poorly populated and it has long been recognized that a fusion spectrum neutron source will be required, the facility IFMIF being the present proposal. Re-evaluation of the regulatory approach for the EU proposed DEMO device shows that the purpose of the source can be changed from...
Article
Full-text available
Electron storage rings used for the production of synchrotron radiation (SR) have an output photon brightness that is limited by the equilibrium beam emittance. By using interleaved injection and ejection of bunches from a source with repetition rate greater than 1 kHz, we show that it is practicable to overcome this limit in rings of energy ~1 GeV...
Article
Full-text available
In a fixed-field alternating-gradient (FFAG) accelerator, eliminating pulsed magnet operation permits rapid acceleration to synchrotron energies, but with a much higher beam-pulse repetition rate. Conceived in the 1950s, FFAGs are enjoying renewed interest, fuelled by the need to rapidly accelerate unstable muons for future high-energy physics coll...
Preprint
Full-text available
The determination of relative stopping power (RSP) via proton computed tomography (pCT) of a patient is dependent in part on the knowledge of the incoming proton kinetic energies; the uncertainty in these energies is in turn determined by the proton source -- typically a cyclotron. Here we show that reducing the incident proton beam energy spread m...
Article
There is an increasing interest in employing technologies to decarbonise the shipping sector; one option is the use of nuclear energy to power civilian ships. Previous work has investigated the use of UO2 fuel and its behaviour in a novel, soluble-boron-free, low power density PWR that offered a 15 year core life to power a container ship with a de...
Article
Full-text available
Attosecond duration relativistic electron bunches travelling through an undulator can generate brilliant coherent radiation in the visible to vacuum ultraviolet spectral range. We present comprehensive numerical simulations to study the properties of coherent emission for a wide range of electron energies and bunch durations, including space-charge...
Article
Full-text available
Quasimonochromatic x rays are difficult to produce above 100 keV, but have a number of uses in x-ray and nuclear science, particularly in the analysis of transuranic species. Inverse Compton scattering (ICS) is capable of fulfilling this need, producing photon beams with properties and energies well beyond the limits of typical synchrotron radiatio...
Article
Full-text available
Boron carbide is a material proposed as an alternative to graphite for use as an energy degrader in proton therapy facilities, and is favoured due to its mechanical robustness and promise to give lower lateral scattering for a given energy loss. However, the mean excitation energy of boron carbide has not yet been directly measured. Here we present...
Article
Full-text available
There is limited validation of MONK using ²³²Th/²³³U benchmarks, and existing validation of Monte Carlo codes has generally used older nuclear data libraries. Here we use MONK-9A to systematically study a series of thermal ²³²Th/²³³U-based benchmark experiments, taken from the International Criticality Safety Benchmark Evaluation Project handbook a...
Preprint
Full-text available
In proton therapy both the energy, which determines the range, and the distal slope, which reflects the rate at which the protons decelerate, are of import if we are to ensure accurate dose deposition and maximum tissue sparing. This publication describes a Geant4 model and presents a two-dimensional polynomial relationship between energy, the ener...
Article
In the UK, one in two people will develop cancer during their lifetimes and radiotherapy (RT) plays a key role in effective treatment. High energy proton beam therapy commenced in the UK National Health Service in 2018. Heavier charged particles have potential advantages over protons by delivering more dose in the Bragg peak, with a sharper penumbr...
Article
Full-text available
There is growing interest in the radiotherapy community in the application of FLASH radiotherapy, wherein the dose is delivered to the entire treatment volume in less than a second. Early pre-clinical evidence suggests that these extremely high dose rates provide significant sparing of healthy tissue compared to conventional radiotherapy without re...
Article
Full-text available
Introduction: Cyclotron-based proton therapy facilities use an energy degrader of variable thickness to deliver beams of the different energies required by a patient treatment plan; scattering and straggling in the degrader give rise to an inherent emittance increase and subsequent particle loss in the downstream energy-selection system (ESS). Here...
Preprint
Full-text available
The use of superconductivity is well-known as a method to increase the average field of a cyclotron and thereby to allow a substantial reduction of its size and mass. We present a compact high-field design for the first superconducting cyclotron with rare-earth (holmium) poles. Our design supports stable acceleration of protons to Ek = 70 MeV with...
Article
Full-text available
If international agreements regarding the need to significantly reduce greenhouse gas emissions are to be met then there is a high probability that the shipping industry will have to dramatically reduce its greenhouse gas emissions. For emission reductions from ships greater than around 40% then alternatives to fossil fuels - such as nuclear energy...
Preprint
Full-text available
If international agreements regarding the need to significantly reduce greenhouse gas emissions are to be met then there is a high probability that the shipping industry will have to dramatically reduce its greenhouse gas emissions. For emission reductions from ships greater than around 40\% then alternatives to fossil fuels - such as nuclear energ...
Article
Purpose The development of 4DCT imaging allows clinicians to account for movement of both the target tumour and organs at risk, although the choice of method of image reconstruction can impact how accurately observers can contour nearby organs. Motion-compensated (MC) image reconstruction is a technique that reduces blurring compared to standard av...
Preprint
Full-text available
The neutrino beam produced from muons decaying in a storage ring would be an ideal tool for precise neutrino cross section measurements and search for sterile neutrinos due to its precisely known flavour content and spectrum. In the proposed nuSTORM facility pions would be directly injected into a racetrack storage ring, where circulating muon beam...
Article
Full-text available
NORMA is a design for a normal-conducting racetrack fixed-field alternating-gradient accelerator for protons from 50 to 350 MeV. In this article we show the development from an idealized lattice to a design implemented with field maps from rigorous two-dimensional (2D) and three-dimensional (3D) FEM magnet modeling. We show that whilst the fields f...
Article
The development and validation of a beam line MC model is an essential part of many projects, particularly those involving particle therapy. This is often a very time consuming and sometimes costly computational process. However, many experiments use the same beam lines and the medical physics community would benefit greatly from a structured code...
Article
Full-text available
NORMA is a design for a normal-conducting race track fixed-field alternating-gradient accelerator (FFAG) for protons from 30 to 350 MeV. In this article we show the development from the nominal lattice design to a model implemented with field maps from 2D and 3D FEM magnet designs. We show that while the fields from the 2D model are sufficient, adj...
Article
Full-text available
In this paper we present a proof to show that there exists no system of linear or nonlinear optics which can simultaneously close multiple local orbit bumps and dispersion through a single beam transport region. The second combiner ring in the CLIC drive beam recombination system, CR2, is used as an example of where such conditions are necessary. W...
Conference Paper
Full-text available
Conventional proton cyclotrons are practically limited by relativistic effects to energies around 250 MeV, sufficient to conduct proton therapy of adults but not for full-body proton tomography. We present an adaptation of the cyclinac scheme for proton imaging, in which a c.250 MeV cyclotron used for treatment feeds a linac that delivers a lower i...
Article
This conceptual design report describes the technical facility for the IsoDAR electron-antineutrino source at KamLAND. The IsoDAR source will allow an impressive program of neutrino oscillation and electroweak physics to be performed at KamLAND. This report provides information on the physics case, the conceptual design for the subsystems, alternat...
Article
Full-text available
In this paper we present a new lattice design for a 30–350 MeV scaling fixed-field alternating gradient accelerator for proton therapy and tomography—NORMA (NOrmal-conducting Racetrack Medical Accelerator). The energy range allows the realization of proton computed tomography and utilizes normal conducting magnets in both a conventional circular ri...
Article
Full-text available
The past few years have seen significant developments both of the technologies available for proton and other charged particle therapies, and of the number and spread of therapy centres. In this review we give an overview of these technology developments, and outline the principal challenges and opportunities we see as important in the next decade....
Article
Full-text available
In this paper we present a proof to show that there exists no system of linear or nonlinear optics which can simultaneously close multiple local orbit bumps and dispersion through a single beam transport region. The second combiner ring in the CLIC drive beam recombination system, CR2, is used as an example of where such conditions are necessary. W...
Conference Paper
Full-text available
When delivering proton therapy, dose accuracy can be aided by the use of Monte Carlo (MC) simulation, but very large numbers of incident particles must be followed to obtain good statistical uncertainty. To validate dose estimates from pencil beam approximations within the treatment field typically requires at least 10 million primaries. The recent...
Article
Full-text available
In a fixed-field alternating-gradient (FFAG) accelerator, eliminating pulsed magnet operation permits rapid acceleration to synchrotron energies, but with a much higher beam-pulse repetition rate. Conceived in the 1950s, FFAGs are enjoying renewed interest, fuelled by the need to rapidly accelerate unstable muons for future high-energy physics coll...
Article
Full-text available
We present PyZgoubi, a framework that has been developed based on the tracking engine Zgoubi to model, optimise and visualise the dynamics in particle accelerators, especially fixed-field alternating-gradient (FFAG) accelerators. We show that PyZgoubi abstracts Zgoubi by wrapping it in an easy-to-use Python framework in order to allow simple constr...
Article
Full-text available
The UK has no research nuclear reactors and relies on the importation of 99Mo and other medical radioisotopes (e.g. Iodine-131) from overseas (excluding PET radioisotopes). The UK is therefore vulnerable not only to global shortages, but to problems with shipping and importation of the products. In this context Professor Erika Denton UK national Cl...
Conference Paper
The primary advantage of proton beam therapy as a cancer treatment is its ability to maximize the radiation dose delivered to the target volume and minimize the dose to surrounding healthy tissue, due to the inherently narrow Bragg peak at the end of the proton range. This can be further enhanced by imaging the target volume and surrounding t...
Article
Full-text available
We discuss the use of two novel techniques to deliver low emittance from a compact electron ring at energies around 1 GeV, suitable for EUV and soft X-ray synchrotron radiation production. The first method is the circulation of nonequilibrium electron bunches, which is made feasible using high repetition rate linacs and very fast bunch-by-bunch inj...
Article
We present a design for a 30-350 MeV scaling racetrack FFAG accelerator for medical application - NORMA (NOrmal-conducting Racetrack Medical Accelerator)-which utilises normal-conducting magnets. NORMA consists of 12 FDF triplet cells with a maximum drift length of ∼2 m; an additional drift space inserted into two places forms a racetrack lattice w...
Conference Paper
Full-text available
In the nominal EMMA design, particles are accelerated rapidly in the serpentine channel between RF buckets. Many integer tunes are crossed in less than a turn in this regime without significant amplitude growth. Slower acceleration inside an RF bucket in EMMA allowed the exploration of slower integer tune crossing speeds. The effect on the coherent...
Article
Full-text available
Recent and ongoing shortages in reactor-based supplies of molybdenum-99 for hospital production of the important medical radioisotope Technetium-99m have prompted the re-examination of the alternative production methods using conventional and laser-based particle accelerators. At present the UK has no domestic source of molybdenum-99 and relies exc...
Article
Full-text preprints here: http://www.tandfonline.com/eprint/5VjmpQcNhE2uNTjecmBA/full Over the last twenty years the treatment of cancer with protons and light nuclei such as carbon ions has moved from being the preserve of research laboratories into widespread clinical use. A number of choices now exist for the creation and delivery of these part...
Article
Full-text available
The discovery by the ATLAS and CMS experiments of a new boson with mass around 125 GeV and with measured properties compatible with those of a Standard-Model Higgs boson, coupled with the absence of discoveries of phenomena beyond the Standard Model up to scales of several hundred GeV, has triggered interest in ideas for future Higgs factories. A n...
Article
Full-text available
This report describes the conceptual design of a proposed free electron laser test facility called CLARA that will be a major upgrade to the existing VELA accelerator test facility at Daresbury Laboratory in the UK. CLARA will be able to test a number of new free electron laser schemes that have been proposed but require a proof of principle experi...
Article
Full-text available
The discovery by the ATLAS and CMS experiments of a new boson with mass around 125 GeV and with measured properties compatible with those of a Standard-Model Higgs boson, coupled with the absence of discoveries of phenomena beyond the Standard Model at the TeV scale, has triggered interest in ideas for future Higgs factories. A new circular e+e− co...
Article
Full-text available
The next generation of lepton flavor violation experiments need high intensity and high quality muon beams. Production of such beams requires sending a short, high intensity proton pulse to the pion production target, capturing pions and collecting the resulting muons in the large acceptance transport system. The substantial increase of beam qualit...
Article
Full-text available
Recent developments for the delivery of proton and ion beam therapy have been significant, and a number of technological solutions now exist for the creation and utilisation of these particles for the treatment of cancer. In this paper we review the historical development of particle accelerators used for external beam radiotherapy and discuss the...
Conference Paper
Full-text available
The materials engineering data base relevant to fusion irradiation is poorly populated and it has long been recognized that a fusion spectrum neutron source will be required, the facility IFMIF being the present proposal. Reevaluation of the regulatory approach for the EU proposed DEMO device shows that the purpose of the source can be changed from...
Article
Full-text available
The conceptual design for a nonscaling fixed field alternating gradient accelerator suitable for charged particle therapy (the use of protons and other light ions to treat some forms of cancer) is described.
Article
Full-text available
EMMA is the worlds first non-scaling FFAG, based at Daresbury Laboratory. EMMA has a very large acceptance and has demonstrated acceleration in the serpentine channel. PRISM (Phase Rotated Intense Slow Muon source) is a next generation muon to electron conversion experiment aiming to obtain intense quasi-monochromatic low energy muon beams by perfo...