Publications
137 results found
Bosco A, Boorman G, Emery S, et al., 2013, Description of laser transport and delivery system for the FETS laserwire emittance scanner, Pages: 527-530
A beam emittance monitor for H-beams based on laser-induced ions neutralization is being developed at the Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL). In this paper we present a full account of the laser system that will be used for the photo-detachment experiment, the optical transport system and the final delivery assembly. All the relevant measurements such as power, spatial and temporal characteristics of the laser, fiber coupling efficiency and final delivery laser beam parameters will be reported.
Pozimski J, Gibson S, 2013, Particle tracking for the FETS laser wire emittance scanner, Pages: 503-506
The Front End Test Stand (FETS) is an R&D project at Rutherford Appleton Laboratory (RAL) with the aim to demonstrate a high power (60 mA, 3 MeV with 50 pps and 10 % duty cycle), fast chopped H-ion beam. The diagnostics of high power particle beams is difficult, due to the power deposition on diagnostics elements introduced in the beam, so non-invasive instrumentation is highly desirable. The laser wire emittance scanner under construction is based on a photo-detachment process, utilizing the neutralized particles produced in the interaction between Laser and H-beam for beam diagnostics purposes. The principle is appropriate to determine the transversal beam density distribution, as well as the transversal and longitudinal beam emittance behind the RFQ. The instrument will be located at the end of the MEBT with the detachment taking place inside a dipole field. Extensive particle tracking simulations have been performed for various settings of the MEBT quadrupoles to investigate the best placement and size of the 2D scintillating detector, and to determine the range and resolution of the instrument. Additionally the power distribution in the following beam dumps has been determined.
Pozimski J, Aslaninejad M, 2013, Gabor lenses for capture and energy selection of laser driven ion beams in cancer treatment, Laser and Particle Beams, Vol: 31, Pages: 723-733, ISSN: 1469-803X
Peach KJ, Aslaninejad M, Barlow RJ, et al., 2013, Conceptual design of a nonscaling fixed field alternating gradient accelerator for protons and carbon ions for charged particle therapy, Phys. Rev. ST Accel. Beams, Vol: 16, Pages: 030101-030101
Edgecock TR, Caretta O, Davenne T, et al., 2013, High intensity neutrino oscillation facilities in Europe, PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS, Vol: 16, ISSN: 1098-4402
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Mishra S, Aslaninejad M, Letchford A, et al., 2013, Thermal design of the FETS chopper beam dump
Pozimski JK, Aslaninejad M, Dover N, et al., 2013, A Ready-to-use Application of Laser-Plasma Accelerators using Gabor Lenses
Pozimski JK, Aslaninejad M, Posocco PA, 2013, Advanced Gabor Lens Lattice for Medical Applications
Pozimski J, Savage P, Alsari S, et al., 2012, Investigation of space charge compensation at fets, IPAC 2012 - International Particle Accelerator Conference 2012, Pages: 445-447
In order to contribute to the development of high power proton accelerators in the MW range, and to prepare the way for an ISIS upgrade and to contribute to the UK design effort on neutrino factories, a front end test stand (FETS) is being constructed at the Rutherford Appleton Laboratory (RAL) in the UK [1]. 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 ion source and LEBT are operational [2] with the RFQ under manufacture. In the LEBT a high degree of space charge compensation (above 90%) and a rise time of space charge compensation around ~50 sec could be concluded indirectly from measurements. The FETS LEBT was updated to perform a detailed experimental analysis of space charge compensation as a more detailed knowledge is of interest for other high power proton projects. In this paper the results of the experimental work will be presented together with discussion of the findings in respect to beam transport. Copyright © 2012 by IEEE.
Savage P, Pozimski J, Garbayo A, et al., 2012, The manufacture and assembly of the FETS RFQ, IPAC 2012 - International Particle Accelerator Conference 2012, Pages: 3862-3864
The Rutherford Appleton Laboratory (RAL) Front End Test Stand (FETS) uses a 324 MHz 4-vane Radio Frequency Quadrupole (RFQ) to accelerate H- ions from 65keV to 3MeV. The RFQ is a copper structure that has been designed as 4 nominally one metre long assemblies. Each assembly consists of 2 major vanes and 2 minor vanes that are bolted together and sealed using an O ring. The mechanical design for the FETS RFQ is complete and the manufacture is underway. In order to achieve the designed physics performance the vanes must be machined and assembled to high degree of accuracy. This requirement has demanded a tight synergy between the design, manufacture and metrology services. Together they have developed detailed procedures for the manufacturing, inspection, alignment and assembly phases. The key points of these procedures will be detailed in this paper. Copyright © 2012 by IEEE.
Bogacz SA, Morozov VS, Roblin YR, et al., 2012, Recent progress toward a muon recirculating linear accelerator, IPAC 2012 - International Particle Accelerator Conference 2012, Pages: 1422-1424
Both Neutrino Factories (NF) and Muon Colliders (MC) require very rapid accelerationdue to the short lifetime of muons. After a capture and bunching section, a linac raisesthe energy to about 900 MeV, and is followed by one or more Recirculating LinearAccelerators (RLA), possibly followed by a Rapid Cycling Synchnotron (RCS) or Fixed-FieldAlternating Gradient (FFAG) ring. A RLA reuses the expensive RF linac section for a numberof passes at the price of having to deal with different energies within the same linac.Various techniques including pulsed focusing quadruopoles, beta frequency beating, andmultipass arcs have been investigated via simulations to improve the performance and reducethe cost of such RLAs. Copyright © 2012 by IEEE.
Pozimski J, Aslaninejad M, 2012, Gabor lens focusing for medical applications, IPAC 2012 - International Particle Accelerator Conference 2012, Pages: 442-444
The widespread introduction of Hadron therapy for cancer treatment is inhibited by the large costs for the accelerator and treatment facility and the subsequent maintenance costs which reflect into the cost per treatment. In the long term future hadrons accelerated by laser beams could offer compact treatment devices with significantly reduced treatment costs, but at the moment the particle distributions produced by such accelerators do not fulfil the medical requirements by far. Nevertheless steady progress in the field should change the situation in future. Besides the reliable production of a sufficient number of ions at the required energy the formation of a particle beam suitable for treatment from the burst of ions created in the acceleration process is one of the major challenges. While conventional optical systems will be operating at the technical limits which would be contradictory to the cost argument, space charge lenses of the Gabor type might be a cost effective alternative. In this paper a beam line consisting of such lenses will be presented together with particle transport simulations. Copyright © 2012 by IEEE.
Bustinduy I, Mũnoz JL, Madariaga I, et al., 2012, Design and fabrication of the ess-bilbao rfq prototype models, IPAC 2012 - International Particle Accelerator Conference 2012, Pages: 3228-3230
As part of the development of the ESS-Bilbao Accelerator in Spain, two different sets of radio frequency quadrupole (RFQ) models have been developed. A set of four oxygen free high conductivity copper weld test models has been designed and manufactured, in order to test different welding methods as well as other mechanical aspects involved in the fabrication of the RFQ. A 352.2MHz four vane RFQ cold model, 1 meter in length, has also been designed and built in Aluminum. These models serve as a good test bench to investigate the validity of different finite element analysis (FEA) software packages. This is a critical part, since the design of the final RFQ will be based on such simulations. The cold model also includes 16 slug tuners and 8 coupler/pick-up ports, which will allow the use of the bead-pull perturbation method to measure the electric field profile, Q-value and resonant modes. In order to investigate fabrication tolerances, the cold model also includes a longitudinal test modulation in the vanes, which is similar to the one intended for the final RFQ. In addition, it represents a useful tool to explore the influence of the modulations in the electromagnetic design. Copyright © 2012 by IEEE.
Letchford A, Clarke-Gayther M, Faircloth D, et al., 2012, Status of the RAL front end test stand, IPAC 2012 - International Particle Accelerator Conference 2012, Pages: 3856-3858
The Front End Test Stand (FETS) under construction at RAL is a demonstrator for front end systems of a future high power proton linac. Possible applications include a linac upgrade for the ISIS spallation neutron source, new future neutron sources, accelerator driven sub-critical systems, a neutrino factory etc. Designed to deliver a 60mA H-minus beam at 3MeV with a 10% duty factor, FETS consists of a high brightness ion source, magnetic low energy beam transport (LEBT), 4-vane 324MHz radio frequency quadrupole, medium energy beam transport (MEBT) containing a high speed beam chopper plus comprehensive diagnostics. This paper describes the current status of the project and future plans. Copyright © 2012 by IEEE.
Kurup A, Bontoiu C, Aslaninejad M, et al., 2011, The muon linac for the International Design Study for the Neutrino Factory, IPAC 2011 - 2nd International Particle Accelerator Conference, Pages: 838-840
The first stage of muon acceleration in the Neutrino Factory utilises a superconducting linac to accelerate muons from 244 MeV to 900 MeV. The linac was split into three types of cryomodules with decreasing magnetic fields and increasing amounts of RF voltage but with the design of the superconducting solenoid and RF cavities being the same for all cryomodules. The current status of the muon linac for the International Design Study for the Neutrino Factory will be presented including a final lattice design of the linac and tracking simulations. Copyright © 2011 by IPAC'11/EPS-AG.
Pozimski JK, Letchford AP, Clarke-Gayther MA, et al., 2011, Status of the fets commissioning and comparison with particle tracking results, Proceedings - 25th Linear Accelerator Conference, LINAC 2010, Pages: 461-463
In order to contribute to the development of high power proton accelerators in the MW range, to prepare the way for an ISIS upgrade [1] and to contribute to the UK design effort on neutrino factories [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 status of the FETS will be given together with experimental results from the commissioning of the LEBT [5] and optimisation of the ion source [4]. Based on the latest experimental results beam transport simulations have been performed for the whole of FETS and the results will be compared with simulations based on older beam data. Previous measurements in the early phase of the project showed that the emittance of the beam delivered by the ion source exceeded our expectations by more than a factor of 3. Since then various changes in the beam extraction/post accelerator region reduced the beam emittance more than a factor of 2. Additionally the LEBT was being commissioned in spring/summer 2010 and the latest experimental data behind the LEBT is available and was compared with beam transport simulations [6,7].
Lawrie S, Letchford A, Pozimski J, et al., 2011, Simulations to flatten the field of the FETS RFQ, IPAC 2011 - 2nd International Particle Accelerator Conference, Pages: 223-225
A high performance radio frequency quadrupole (RFQ) is the next major component to be installed at the front end test stand (FETS) at the Rutherford Appleton laboratory (RAL) in the UK. Apart from minor tweaks, the beam dynamics, RF, thermal and mechanical designs of the RFQ are complete. The copper has been purchased and machining is expected to commence in September. This report summarizes the simulation work performed to ensure the RF design is sound. This includes performance studies of the end-wall dipole suppression fingers, tuning the frequency of the input and output vane end regions and implementing a simple solution to remove modulation induced field tilt. Copyright © 2011 by IPAC'11/EPS-AG.
Long K, Pozimski J, 2011, The international design study for the neutrino factory, IPAC 2011 - 2nd International Particle Accelerator Conference, Pages: 847-849
The International Design Study for the Neutrino Factory (the IDS-NF) has recently completed the Interim Design Report (IDR) for the facility as a step on the way to the Reference Design Report (RDR). The IDR has two functions: it marks the point in the IDS-NF at which the emphasis turns to the engineering studies required to deliver the RDR and it documents the present baseline design for the facility which will provide 1021 muon decays per year from 25 GeV stored muon beams. The facility will serve two neutrino detectors; one situated at a source-detector distance of between 2500-5000 km, the second at 7000-8000 km. The conceptual design of the accelerator facility will be described and its performance will be summarized. Copyright © 2011 by IPAC'11/EPS-AG.
Back J, Pozimski J, Savage P, et al., 2010, Commissioning of the low energy beam transport of the front end test stand, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 648-650
The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory is intended to demonstrate the early stages of acceleration (0-3 MeV) and beam chopping required for high power proton accelerators, including proton drivers for pulsed neutron spallation sources and neutrino factories. A Low Energy Beam Transport (LEBT), consisting of three solenoids and four drift sections, is used to transport the H- beam from the ion source to the FETS Radio Frequency Quadrupole. We present the status of the installation and commissioning of the LEBT, and compare particle dynamics simulations with preliminary measurements of the H- beam transport through the LEBT.
Alsari S, Pozimski JK, Savage P, et al., 2010, A tuning system for the FETS RFQ, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 651-653
The Front End Test Stand (FETS) is an experiment based at the Rutherford Appleton Laboratory (RAL) in the UK. The test stand is being constructed in collaboration between STFC, Imperial College London, ASTeC, the University of Warwick and the Universidad del Pais Vasco. This experiment will design, build and test the first stages necessary to produce a very high quality, chopped H- ion beam as required for the next generation of high power proton accelerators (HPPAs). HPPAs with beam powers in the megawatt range have many possible applications including drivers for spallation neutron sources, neutrino factories, accelerator driven sub-critical systems, waste transmuters and tritium production facilities. An automatic tuning system has been developed for the main 324MHz 4-vane RFQ accelerator and has been tested to fine tune the frequency changes due to temperature variation in the resonant frequency of a 324MHz 4-vane cold model RFQ, which been designed as part of the development of the test stand. This paper will present the electronics design of the automated tuning system along with the mechanical tuner structure. The design concepts will be discussed. Furthermore, results of the RF tuning would be presented.
Bonţoiu C, Aslaninejad M, Pozimski J, et al., 2010, Beam dynamics studies for the first muon linac of the neutrnio factory, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 4590-4592
Within the Neutrino Factory Project the muon acceleration process involves a complex chain of accelerators including a (single-pass) linac, two recirculating linacs and an FFAG. The linac consists of RF cavities and iron shielded solenoids for transverse focusing and has been previously designed relying on idealized field models. However, to predict accurately the transport and acceleration of a high emittance 30 cm wide beam with 10 % energy spread requires detailed knowledge of fringe field distributions. This article presents results of the front-to-end tracking of the muon beam through numerically simulated realistic field distributions for the shielded solenoids and the RF fields. Real and phase space evolution of the beam has been studied along the linac and the results are presented and discussed.
Savage P, Alsari S, Jolly S, et al., 2010, The mechanical engineering design of the FETS RFQ, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 810-812
This paper will present the mechanical engineering design for a 324 MHz 4-vane RFQ, which has been developed for the Front End Test Stand (FETS) project based at the Rutherford Appleton Laboratory (RAL) in the UK. The design criteria will be discussed along with particular design features of the RFQ including the tuners, vacuum ports, main body cooling pocket design and the support/alignment structure. Different techniques for creating the RF and vacuum seal between major and minor vanes are also discussed.
Gabor C, Boorman GE, Bosco A, et al., 2010, Status report of the ral photo-detachment beam profile monitor, HB 2010 - 46th ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams, Pages: 492-496
The Rutherford Appleton Laboratory (RAL) is developing a front end suitable for High Power Proton Applications HPPA. The main components are an H - ion source with up to 60 mA current at 65 keV, a transport section to match the beam to an RFQ with 3 MeV output energy and a LEBT comprising a chopper system with several buncher cavities. Photo detachment can be used as a non-destructive diagnostics method. The paper reports on progress with a beam profile monitor that is placed in a pumping vessel right after the ion source at the intersection to the Low Energy Beam Transport (LEBT). This diagnostics tool consists of mirrors inside the vacuum to scan the laser beam through the beam, the actual detector to measure photo detached electrons, laser and optics outside the vacuum and electronics to amplify and read out the signal. The paper summarizes the experimental set-up and status, discusses problems and presents recent measurements.
Bustinduy I, De Cos D, Feuchtwanger J, et al., 2010, First LEBT simulations for the Bilbao Accelerator ion source test stand, HB 2010 - 46th ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams, Pages: 595-599
The proposed multi-specimen Low Energy Transport System (LEBT) consists of a series of solenoids with tunable magnetic fields, used to match the characteristics of the beam to those imposed by the RFQ input specification. The design of the LEBT involves selecting the number of solenoids to use and their fixed positions, so that a set of fields that provides the desired matching can be found for any given conditions (different currents, input emittances, etc). In this work we present the first simulations carried out to design the Bilbao Accelerator LEBT, which were performed using several codes (TRACK, GPT, Trace2D). The best configuration is discussed and evaluated in terms of the degree of matching to the RFQ input requirements.
Lawrie S, Faircloth D, Letchford A, et al., 2010, Assessing the transmission of the H<sup>-</sup> ion beam on the front end test stand, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 813-815
The front end test stand (FETS) [1] is entering the next stage of construction and commissioning, with the threesolenoid magnetic low energy beam transport (LEBT) line being installed. A thorough characterization of the beam leaving the Penning H- ion source has been performed. This includes measurements of the beam current using toroids and of the transverse emittance using slit-slit scanners. These measurements are performed over a wide range of source discharge and extraction parameters in order to understand how the transmission may be improved. Comments on the quality of the beam to be injected into the FETS radio frequency quadrupole (RFQ) are given.
Lawrie S, Letchford A, Pozimski J, et al., 2010, Combined electromagnetic-thermal-structural simulation of the four-metre radio frequency quadrupole to be installed on the front end test stand, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 816-818
The front end test stand (FETS) [1] being constructed at the Rutherford Appleton Laboratory is entering the next stage of commissioning, with the three-solenoid magnetic low energy beam transport (LEBT) now installed and undergoing commissioning. The next major component to be manufactured is the 3 MeV, 324 MHz, four metre radio frequency quadrupole (RFQ). The mechanical design is almost complete so a comprehensive finite element model of the entire RFQ has been made in ANSYS to ensure the electromagnetic, thermal and structural properties are sound. An analysis of the cooling strategy and expected resonant frequency shift due to thermal expansion are presented.
Aslaninejad M, Bontoiu C, Pasternak J, et al., 2010, Solenoid fringe field effects for the neutrino factory Linac - Mad-X investigation, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 3963-3965
International Design Study for the Neutrino Factory (IDS-NF) assumes the first stage of muon acceleration (up to 900 MeV) to be implemented with a solenoid based Linac. The Linac consists of three styles of cryo-modules, containing focusing solenoids and varying number of SRF cavities for acceleration. Fringe fields of the solenoids and the focusing effects in the SRF cavities have significant impact on the transverse beam dynamics. Using an analytical formula, the effects of fringe fields are studied in MAD-X. The resulting betatron functions are compared with the results of beam dynamics simulations using OptiM code.
Pozimski J, Aslaninejad M, Bontoiu C, et al., 2010, Investigation of beam loading effects for the Neutrino Factory muon accelerator, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 3479-3481
The International design study (IDS) study showed that a Neutrino Factory [1] seems to be the most promising candidate for the next phase of high precision neutrino oscillation experiments. One part of the increased precision is due to the fact that in a Neutrino Factory the decay of muons produces a neutrino beam with narrow energy distribution and divergence. The effect of beam loading on the energy distribution of the muon beam in the Neutrino Factory decay rings has been investigated numerically. The simulations have been performed using the baseline accelerator design including cavities for different number of bunch trains and bunch train timing. A detailed analysis of the beam energy distribution expected is given together with a discussion of the energy spread produced by the gutter acceleration in the FFAG and the implications for the neutrino oscillation experiments will be presented.
Jolly S, Easton M, Pozimski J, et al., 2010, Integrated design method and beam dynamics simulations for the FETS radiofrequency quadrupole, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 645-647
A 4m-long, 324MHz four-vane RFQ, consisting of four coupled sections, is currently being designed for the Front End Test Stand (FETS) at RAL in the UK. A novel design method, integrating the CAD and electromagnetic design of the RFQ with beam dynamics simulations, is being used to optimise the design of the RFQ. Basic RFQ parameters are produced with the RFQSIM code. A full CAD model of the RFQ vane tips is produced in Autodesk Inventor, based upon these parameters. This model is then imported into a field mapping code to produce a simulation of the electrostatic field around the vane tips. This field map is then used to model the beam dynamics within the RFQ using General Particle Tracer (GPT). Previous studies have been carried out using field mapping in CST EM Studio. A more advanced technique using Comsol Multiphysics and Matlab, that more tightly integrates the CAD modelling, field mapping and beam dynamics simulations, is described. Results using this new method are presented and compared to the previous optimisation process using field maps from CST.
Peach K, Cobb J, Sheehy SL, et al., 2010, Pamela overview and status, IPAC 2010 - 1st International Particle Accelerator Conference, Pages: 112-114
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.
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