Publications
137 results found
De Cos D, Bustinduy I, Feuchtwanger J, et al., 2010, Beam dynamic studies on the radio-frequency quadrupole for the Bilbao accelerator, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 4214-4216
The main objective of the Bilbao Front End Test Stand (ETORFETS) is to set up a facility to demonstrate experimentally the design ideas for the future ESS LINAC that are being proposed in discussion forums by the technical scientific community. ETORFETS is focused on the first stage of the linear accelerator, namely, that of the Radio-Frequency Quadrupole (RFQ) and its pre and post beam transport systems. The RFQ bunches, focuses transverse and longitudinally, and accelerates charged particles in the low-energy range, thus becoming one of the main components of the accelerating structure. The first RFQ design and tracking simulations, performed with Alan Letchford's RFQSIM code, will be presented in this work.
Easton MJ, Aslaninejad M, Jolly S, et al., 2010, Design optimisation and particle tracking simulations for PAMELA injector RFQ, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 822-824
The PAMELA project aims to design an ns-FFAG accelerator for cancer therapy using protons and carbon ions [1]. For the injection system for carbon ions, an RFQ is one option for the first stage of acceleration. Our integrated RFQ design process [1] has been further developed using Comsol Multiphysics for electric field modelling. The design parameters for the RFQ are automatically converted to a CAD model using Autodesk Inventor, and the electric field map for this model is simulated in Comsol. Particles are then tracked through this field map using Pulsar Physics' General Particle Tracer (GPT). Our software uses Visual Basic for Applications and MATLAB to automate this process and allow for optimisation of the RFQ design parameters based on particle dynamical considerations. Possible designs for the PAMELA RFQ, including super-conducting and normalconducting solutions, are presented and discussed, together with results of the field map simulations and particle tracking for these designs.
Letchford A, Clarke-Gayther MA, Faircloth D, et al., 2010, Status of the RAL front end test stand, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 642-644
The Front End Test Stand (FETS) under construction at the Rutherford Appleton Laboratory is the UK's contribution to research into the next generation of High Power Proton Accelerators (HPPAs). HPPAs are an essential part of any future Spallation Neutron Source, Neutrino Factory, Muon Collider, Accelerator Driven Sub-critical System, Waste Transmuter etc. FETS will demonstrate a high quality, high intensity, chopped H-minus beam and is a collaboration between RAL, Imperial College and the Universtity of Warwick in the UK and the Universidad del Pais Vasco and ESS-Bilbao in Spain. This paper describes the current status and future plans of FETS.
Gabor C, Faircloth DC, Lee DA, et al., 2010, Diagnostic experiments at a 3 MeV test stand at Rutherford Appleton Laboratory (United Kingdom), REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 81, ISSN: 0034-6748
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- Citations: 2
Faircloth DC, Lawrie S, Letchford AP, et al., 2010, The front end test stand high performance H<SUP>-</SUP> ion source at Rutherford Appleton Laboratory, REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 81, ISSN: 0034-6748
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- Citations: 10
Lawrie SR, Faircloth DC, Letchford AP, et al., 2010, Plasma meniscus and extraction electrode studies of the ISIS H<SUP>-</SUP> ion source, REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 81, ISSN: 0034-6748
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- Citations: 13
Long K, 2010, The International Design Study for the Neutrino Factory, 35TH INTERNATIONAL CONFERENCE OF HIGH ENERGY PHYSICS (ICHEP 2010)
Jolly S, Pozimski J, Pfister J, et al., 2009, Data acquisition and error analysis for pepperpot emittance measurements, DIPAC 2009 - 9th European Workshop on Beam Diagnostics and Instrumentation for Particle Accelerators, Pages: 421-423
The pepperpot provides a unique and fast method of measuring emittance, providing four dimensional correlated beam measurements for both transverse planes. In order to make such a correlated measurement, the pepper-pot must sample the beam at specific intervals. Such discontinuous data, and the unique characteristics of the pep-perpot assembly, requires special attention be paid to both the data acquisition and the error analysis techniques. A first-principles derivation of the error contribution to the rms emittance is presented, leading to a general formula for emittance error calculation. Two distinct pepperpot systems, currently in use at GSI in Germany and RAL in the UK, are described. The data acquisition process for each system is detailed, covering the reconstruction of the beam profile and the transverse emittances. Error analysis for both systems is presented, using a number of methods to estimate the emittance and associated errors.
Gabor C, Letchford AP, Pozimski JK, 2009, Designreport of a non-destructive emittanceinstrument for rutherford appleton Laboratory's front end test stand FETS, DIPAC 2009 - 9th European Workshop on Beam Diagnostics and Instrumentation for Particle Accelerators, Pages: 213-215
The RAL front end FETS is currently under construction to demonstrate a fast chopped, high power H- ion beam at 3 MeV of up to 18 kW. Therefore emittance instruments should use photo detachment because mechanical parts could be affected by heat loading. This emittance instrument uses a dipole to separate negative ions from produced neutrals and a scintillator to measure particle distribution and deflection. This means a careful design of the diagnostic instrument according to other beam parameters and existing focusing elements because reasonable results require high enough phase space advance. A conceptual design layout will be presented considering the current status of the MEBT simulations along with a discussion are a Penning type ion source, 3 solenoid LEBT, RFQ and the MEBT consisting of quadrupoles, four buncher cavities and the chopper. The emittance diagnostic and beamdump are located at the end of the beamline.
Lee DA, Savage P, Pozimski J, et al., 2009, Status of the laser-based beam profile instrument for the RAL Front End Test Stand, DIPAC 2009 - 9th European Workshop on Beam Diagnostics and Instrumentation for Particle Accelerators, Pages: 393-395
The RAL Front End Test Stand is under construction with the aim of demonstrating production of a high-quality, chopped 60 mA H- beam at 3 MeV and 50 pps. In addition to the accelerator development, novel laser-based diagnostics will be implemented. This paper reports on a device that will be able to measure multiple profiles of the beam density distribution in such a way that the full 2D density distribution can be reconstructed. The device is currently being commissioned. The status of the device is presented together with results of the commissioning and plans for future development.
Gabor C, Prior CR, Letchford AP, et al., 2009, Emittance measurement instrument for a high brilliance H<sup>-</sup> ion beam, Proceedings of the 24th Linear Accelerator Conference, LINAC 2008, Pages: 594-596
Among present challenges for beam diagnostics and instrumentation are issues presented by high beam intensity, brightness, resolution and the need to avoid inserting mechanical parts into the beam. This very often means applying non-destructive methods, which avoid interaction between ions and mechanical parts and, furthermore, allow on-line measurements during normal beam operation. The preferred technique for H- beams is the photo- detachment process where (laser) light within the range of 400. . . 1000 nm has a sufficient continuous cross section σPD to neutralize negative ions. The actual diagnostics are then applied to either the neutrals produced or the electrons. The latter are typically used for beam profiles whereas neutrals are more suitable for emittances, and form the subject of the present paper. This provides an overview of the basic features of the diagnostic technique, followed by discussion about computing the missing second transverse projection view using a method called Maximum Entropy Method (MaxEnt, MEM).
Pozimski J, Letchford A, Back J, et al., 2009, Particle dynamics calculations and emittance measurements at the FETS, Proceedings of the 24th Linear Accelerator Conference, LINAC 2008, Pages: 281-283
In order to contribute to the development of high power proton accelerators in the MW range, to prepare the way for an ISIS upgrade and to contribute to the UK design effort on neutrino factories [1,2], a front end test stand (FETS) is being constructed at the Rutherford Appleton Laboratory (RAL) in the UK [3]. The aim of the FETS is to demonstrate the production of a 60 mA, 2 ms, 50 pps chopped beam at 3 MeV with sufficient beam quality. The results of numerical simulations of the particle dynamics from the charge separation dipole behind the ion source to the end of the MEBT will be presented. Previous measurements showed that the emittance of the beam delivered by the ion source exceeded our expectations by more than a factor of three [4]. Since then various changes in the beam extraction/post accelerator region reduced the beam emittance by nearly a factor of two. Simulations of the particle dynamics in the FETS based on distributions gained from recent measurements of the transversal beam emittance behind the ion source will be presented and the results for different input distributions discussed.
Letchford AP, Clarke-Gayther MA, Faircloth DC, et al., 2009, Status of the ral front end test stand, Proceedings of the 24th Linear Accelerator Conference, LINAC 2008, Pages: 70-72
High power proton accelerators (HPPAs) with beam powers in the several megawatt range have many applications including drivers for spallation neutron sources, neutrino factories, waste transmuters and tritium production facilities. The UK's commitment to the development of the next generation of HPPAs is demonstrated by a test stand being constructed in collaboration between RAL, Imperial College London, the University of Warwick and the Universidad del Pais Vasco, Bilbao. The aim of the RAL Front End Test Stand is to demonstrate that chopped low energy beams of high quality can be produced and is intended to allow generic experiments exploring a variety of operational conditions. This paper describes the current status of the RAL Front End Test Stand.
Lawrie SR, Faircloth DC, Letchford AP, et al., 2009, Redesign of the Analysing Magnet in the ISIS H(-) Penning Ion Source, 1st International Symposium on Negative Ions, Beams and Sources, Publisher: AMER INST PHYSICS, Pages: 253-262, ISSN: 0094-243X
Faircloth DC, Lawrie S, Letchford AP, et al., 2009, Commissioning the Front End Test Stand High Performance H<SUP>-</SUP> Ion Source at RAL, 1st International Symposium on Negative Ions, Beams and Sources, Publisher: AMER INST PHYSICS, Pages: 243-+, ISSN: 0094-243X
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- Citations: 1
Faircloth DC, Letchford AP, Gabor C, et al., 2008, Understanding extraction and beam transport in the ISIS H<SUP>-</SUP> Penning surface plasma ion source, REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 79, ISSN: 0034-6748
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- Citations: 15
Faircloth DC, Whitehead MO, Wood TW, et al., 2008, Study of the post extraction acceleration gap in the ISIS H<sup>-</sup> penning ion source, EPAC 2008 - Contributions to the Proceedings, Pages: 406-408
The RAL Front End Test Stand (FETS) is being constructed to demonstrate a chopped H- beam of up to 60mA at 3 MeV with 50pps and sufficiently high beam quality for future High Power Proton Accelerators (HPPA). The injection energy into the RFQ will be in the range of 60 to 70 keV whereas the standard ISIS H- Penning ion source operates at 35keV, therefore the post extraction acceleration voltage must be increased. In order to finalize the design of the FETS post extraction system, a study is being conducted on the Ion Source Development Rig (ISDR) at ISIS. This study shows how beam transport is affected by different post extraction acceleration voltages and gap lengths. Beam current and 4 dimensional profile measurements are presented along with theoretical calculations.
Letchford AP, Clarke-Gayther MA, Faircloth DC, et al., 2008, Status of the ral front end test stand, EPAC 2008 - Contributions to the Proceedings, Pages: 3437-3439
High power proton accelerators (HPPAs) with beam powers in the several megawatt range have many applications including drivers for spallation neutron sources, neutrino factories, waste transmuters and tritium production facilities. The UK's commitment to the development of the next generation of HPPAs is demonstrated by a test stand being constructed in collaboration between RAL, Imperial College London, the University of Warwick and the Universidad del Pais Vasco, Bilbao. The aim of the RAL Front End Test Stand is to demonstrate that chopped low energy beams of high quality can be produced and is intended to allow generic experiments exploring a variety of operational conditions. This paper describes the current status of the RAL Front End Test Stand.
Yokoi T, Cobb J, Peach K, et al., 2008, Beam injection issues of FFAG for particle therapy, EPAC 2008 - Contributions to the Proceedings, Pages: 3401-3403
Spot scanning irradiation is a novel and powerful scheme for particle therapy. The pulsed beam structure of FFAG (Fixed Field Alternating Gradient) accelerator is suitable for the scheme. In order to form an uniform dose distribution in a target volume, Beam intensity must be modulated in sync with beam energy modulation. The intensity modulation requires precise intensity control and constrain the bunch intensity of accelerator of pulsed beam structure. In the paper, injection related issue, that is the intensity modulation of FFAG accelerator, is discussed from the view point of spot scanning.
Jolly S, Kurup A, Lee D, et al., 2008, Detailed study of the RF properties of the FETs RFQ COLD model, EPAC 2008 - Contributions to the Proceedings, Pages: 3422-3424
A 324MHz four vane RFQ cold model has been built, as part of the development of a proton driver Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) in the UK. Previous measurements to determine the electric field profile were made using the bead-pull perturbation method: these measurements have been refined and expanded. New measurements of the electric field profile, Q-value and resonant modes are presented. Measurements of the fundamental frequency and Q-value of the RFQ as a result of modifications to the profile of the end flange inserts are also given. Finally, an experiment is outlined to determine the beam transmission properties of the cold model based on beam transport simulations with the General Particle Tracer package (GPT).
Faircloth DC, Letchford AP, Wise P, et al., 2008, Installation of the front end test stand high performance H<sup>-</sup> ion source at RAL, EPAC 2008 - Contributions to the Proceedings, Pages: 412-414
The RAL Front End Test Stand (FETS) is being constructed to demonstrate a chopped H- beam of up to 60 mA at 3 MeV with 50 pps and sufficiently high beam quality for future high-power proton accelerators (HPPA). This paper details the first stage of construction - the installation of the ion source.
Lawrie SR, Faircloth DC, Letchford AP, et al., 2008, Modifications to the analysing magnet in the ISIS penning ion source, EPAC 2008 - Contributions to the Proceedings, Pages: 427-429
A full 3D electromagnetic finite element analysis and particle tracking study has been undertaken of the ISIS Penning surface plasma ion source using CST Particle Studio 2008. The existing 90° analysing magnet is found to have a sub-optimal magnetic field index, causing beam divergence and contributing to beam loss. Different magnet pole piece geometries are modelled and the effect of space charge investigated. Based on this modelling, three new sets of poles are manufactured and tested on the Ion Source Development Rig.
Cheng Y, Savage P, Kurup A, et al., 2007, RFQ cold model RF measurements and waveguide-to-coaxial line transition design for the front-end test stand at RAL, Proceedings of the IEEE Particle Accelerator Conference, Pages: 1655-1657
A 324MHz four vane RFQ cold model has been built, as part of the development of a proton driver front end test stand at the Rutherford Appleton Laboratory (RAL) in the UK. This paper will present the results of RF measurements performed on the cold model, which include analysis of resonant modes, Q-value measurements and electric field profile measurements using a bead-pull perturbation method. These measurements were done before and after brazing of the four vanes and the results were compared to Microwave Studio simulations. Additionally, a tuner has been designed, built and tested and the results will be presented together with the preliminary results of the electromagnetic design of waveguide-to-coaxial line transition structures for the four vane RFQ. ©2007 IEEE.
Letchford A, Faircloth D, Daly A, et al., 2007, Status report on the RAL front end test stand, Proceedings of the IEEE Particle Accelerator Conference, Pages: 1634-1636
High power proton accelerators (HPPAs) with beam powers in the several megawatt range have many applications including drivers for spallation neutron sources [1], neutrino factories [2], waste transmuters and tritium production facilities. The UK's commitment to the development of the next generation of HPPAs is demonstrated by a test stand being constructed in collaboration between RAL, Imperial College London, the University of Warwick and the Universidad del Pais Vasco. The aim of the RAL Front End Test Stand is to demonstrate that chopped low energy beams of high quality can be produced and is intended to allow generic experiments exploring a variety of operational conditions. This paper describes the status of the RAL Front End Test Stand ©2007 IEEE.
Lee DA, Pozimski JK, Gabor C, et al., 2007, A laserwire beam profile measuring device for the ral Front End Test Stand, 8th European Workshop on Beam Diagnostics and Instrumentation for Particle Accelerators, DIPAC 2007, Pages: 81-83
The Front End Test Stand (FETS) [1] at the Rutherford Appleton Laboratory (RAL) is being developed to demonstrate a chopped H- beam of 60 mA at 3 MeV with 50 pps and sufficiently high beam quality for future highpower proton accelerators. As such, it requires a suite of diagnostic instruments to provide detailed measurements of the ion beam properties [2]. Due to the high beam brightness and a desire to have online instrumentation while the accelerator is operational, a series of non-intrusive and non-destructive diagnostics based on laser-detachment are being developed. In this paper, the principle behind the laser-based diagnostic instruments is given and the progress [3] that has been made towards the construction of a laserwire instrument that can measure the beam profile at an arbitrary angle is described. In particular, the results of field distribution and particle tracking simulations are shown and the design of the instrument and the vacuum vessel in which it will be mounted are presented. The software that will be used to reconstruct the 2D transverse beam density distribution from the beam profiles is also described.
Jolly S, Lee D, Pozimski J, et al., 2007, Beam diagnostics for the Front End Test Stand at RAL, 8th European Workshop on Beam Diagnostics and Instrumentation for Particle Accelerators, DIPAC 2007, Pages: 218-220
The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) is intended to demonstrate the production of a 60mA, 2ms, 50pps chopped beam required for future high power proton accelerators. A number of different diagnostic systems are currently under development to provide precise measurements of the H- ion beam produced by the FETS ion source. A pepperpot emittance measurement system, which is also capable of high resolution transverse beam density measurements, has been designed for use on the ion source development rig. This system is capable of sub-microsecond time-resolved measurements at a range of positions along the beam axis. Details are given of the current design, with recent emittance and beam profile measurements presented.
Barlow RJ, Pozimski JK, Peach K, et al., 2007, The CONFORM project: Construction of a nonscaling FFAG and its applications, Proceedings of the IEEE Particle Accelerator Conference, Pages: 2886-2888
The CONFORM project, recently funded as part of the UK 'Basic Technology' initiative, will build a 20 MeV Non-Scaling FFAG (EMMA) at Daresbury. The experience gained will be used for the design of a proton machine (PAMELA) for medical research, and other applications for Non-Scaling FFAGs in different regimes will be explored. The successful development of this type of accelerator will provide many opportunities for increased exploitation, especially for hadron therapy for treatment of tumours, and the project provides a framework where machine builders will work with potential user communities to maximise the synergies and help this to happen successfully. ©2007 IEEE.
Peach K, Cobb J, Yokoi T, et al., 2007, PAMELA - A model for an FFAG based hadron therapy machine, Proceedings of the IEEE Particle Accelerator Conference, Pages: 2880-2882
Approximately one third of the world's 15000 accelerators are used for tumour therapy and other medical applications [1]. The characteristics of FFAGs make them ideally suited to such applications, as the much smaller magnet size and greater compactness offers considerable cost and operational benefits. In the first stage the work on PAMELA will focus on the optimization of the FFAG design to deliver the specific machine parameters demanded by therapy applications. In this phase of the PAMELA project the effort will concentrate on the design of a semi-scaling type FFAGs to deliver a 450 MeV/u carbon ion beam, including detailed lattice and tracking studies. The second stage will use the existing expertise in the BASROC consortium [2] to undertake a design of the magnets and RF system for PAMELA. An outline of the overall concept of PAMELA will be discussed and the actual status of the work will be presented. ©2007 IEEE.
Cheng Y, Savage P, Kurup A, et al., 2007, RFQ cold model RF measurements and waveguide-to-coaxial line transition design for the front-end test stand at RAL, IEEE Particle Accelerator Conference, Publisher: IEEE, Pages: 2876-+
Letchford A, Faircloth D, Daly A, et al., 2007, Status report on the RAL Front End Test Stand, IEEE Particle Accelerator Conference, Publisher: IEEE, Pages: 2855-+
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