IPAC2014 - List of Authors (Lawrie, S.R.)

Paper	Title	Page
MOPRI014	Extracting a High Current Long Pulse Hminus Beam for FETS	611
	D.C. Faircloth, M. Cannon, S.R. Lawrie, M. Perkins STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) requires a 60 mA 2 ms 50 Hz Hminus beam. A Penning Surface Plasma Source is used to produce the beam. This paper gives the latest results obtained using a new 25 kV long pulse extraction power supply designed and built at RAL. Power supply performance, beam current and emittance are detailed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI014
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MOPRI015	Installing the VESPA H⁻ Ion Source Test Stand at RAL	614
	S.R. Lawrie, D.C. Faircloth, A.P. Letchford, M. Perkins, M. Whitehead, T. Wood STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	A Penning-type negative hydrogen (H) ion source has been used reliably on the ISIS pulsed spallation neutron and muon facility at the Rutherford Appleton Laboratory (RAL) in the UK for almost 30 years. However a detailed study of the ion source plasma and extraction has never been undertaken. If these properties were known, the beam emittance and losses due to collimation could be reduced, and the lifetime increased. This paper summarises the progress made on installing a Vessel for Extraction and Source Plasma Analyses (VESPA) to fill the knowledge gap.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI015
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TUPRO072	Lattice and Component Design for the Front End Test Stand MEBT at RAL	1205
	M. Aslaninejad, J.K. Pozimski, P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom M.A. Clarke-Gayther, A.P. Letchford, D.C. Plostinar STFC/RAL, Chilton, Didcot, Oxon, United Kingdom S.R. Lawrie STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The Front End Test Stand (FETS) linear accelerator at Rutherford Appleton laboratory (RAL) will accelerate a 60 mA, 2 ms, 50 pps H⁻ beam to 3MeV. The aim of FETS is to demonstrate perfect chopping using a novel 2 stage (fast / slow) chopper scheme. The beam chopper and associated beam dumps are located in the MEBT. Achieving a low emittance-growth under the influence of strong, non-linear space-charge forces in a lattice which has to accommodate the long chopping elements is challenging. The baseline FETS MEBT design is 4.3 m long and contains 7 quadrupoles, 3 rebunching cavities, a fast and slow chopper deflector and two beam dumps. In particle dynamics simulations using a distribution from an RFQ simulation as input, beam loss for the un-chopped beam is below 1% while the chopping efficiency is >99 % in both choppers. The final MEBT lattice chosen for FETS will be presented together with particle tracking results and design details of the beam line components.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO072
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THPME073	Performance of the Low Energy Beam Transport at the RAL Front End Test Stand	3406
	J.J. Back University of Warwick, Coventry, United Kingdom D.C. Faircloth, A.P. Letchford STFC/RAL, Chilton, Didcot, Oxon, United Kingdom C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom S.R. Lawrie STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) 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 Radio Frequency Quadrupole (RFQ). We present the current performance of the LEBT with regards to beam alignment, transmission and focusing into the acceptance of the RFQ.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME073
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THPME186	Development of a BPM System using a Commercial FPGA Card and Digitizer Adaptor Module for FETS	3716
	G.E. Boorman, S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom R.T.P. D'Arcy, S. Jolly UCL, London, United Kingdom S.R. Lawrie, A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	A series of beam position monitors (BPMs) will be installed at the Front End Test Stand (FETS) at RAL as part of the 3 MeV Medium Energy Beam Transport (MEBT). The BPMs analyse 2 ms long, 60 mA beam pulses delivered to the MEBT by a 324 MHz Radio Frequency Quadrupole (RFQ). Initial linearity and resolution measurements from the prototype button BPMs are shown. The development of the algorithm for the processing of the BPM signals using a commercial PXI-based FPGA card is discussed and initial measurements of the electronics and signal processing are presented. The test-rig used to characterise each BPM and further develop the processing algorithm is described. The position and phase are measured several times throughout the duration of each pulse, and the measurements are made available via an EPICS server.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME186
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THPME191	Simulation Results of the FETS Laserwire Emittance Scanner	3729
	K.O. Kruchinin, A. Bosco, S.M. Gibson, P. Karataev Royal Holloway, University of London, Surrey, United Kingdom D.C. Faircloth STFC/RAL, Chilton, Didcot, Oxon, United Kingdom C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom S.R. Lawrie STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	The Front End Test Stand (FETS) at Rutherford Appleton Laboratory (RAL) has been developed to demonstrate a high current (60 mA) H⁻ beam with the energy of 3 MeV that will be required for future proton drivers. At such high power beam machine a non-invasive diagnostics is required. To measure the emittance of the ion beam a laserwire scanner is being developed. A high power laser will scan across the H⁻ ion beam. The H⁻ particles will be neutralized via a photo-detachment process producing a stream of fast neutral hydrogen atoms bearing information about the phase space distribution of the initial H⁻ beam. To design an effective detection system and optimize its parameters a simulation of the processes at the interaction point is required. We present recent simulation results of theц FETS laserwire system. Simulations were performed using measured data of the laser propagation and ion beam distribution, obtained with General Particle Tracer code.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME191
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Paper

Title

Page

Extracting a High Current Long Pulse Hminus Beam for FETS

611

D.C. Faircloth, M. Cannon, S.R. Lawrie, M. Perkins
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) requires a 60 mA 2 ms 50 Hz Hminus beam. A Penning Surface Plasma Source is used to produce the beam. This paper gives the latest results obtained using a new 25 kV long pulse extraction power supply designed and built at RAL. Power supply performance, beam current and emittance are detailed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI014

Export •

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

MOPRI015

Installing the VESPA H⁻ Ion Source Test Stand at RAL

614

S.R. Lawrie, D.C. Faircloth, A.P. Letchford, M. Perkins, M. Whitehead, T. Wood
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

A Penning-type negative hydrogen (H) ion source has been used reliably on the ISIS pulsed spallation neutron and muon facility at the Rutherford Appleton Laboratory (RAL) in the UK for almost 30 years. However a detailed study of the ion source plasma and extraction has never been undertaken. If these properties were known, the beam emittance and losses due to collimation could be reduced, and the lifetime increased. This paper summarises the progress made on installing a Vessel for Extraction and Source Plasma Analyses (VESPA) to fill the knowledge gap.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI015

Export •

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

TUPRO072

Lattice and Component Design for the Front End Test Stand MEBT at RAL

1205

M. Aslaninejad, J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
M.A. Clarke-Gayther, A.P. Letchford, D.C. Plostinar
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
S.R. Lawrie
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The Front End Test Stand (FETS) linear accelerator at Rutherford Appleton laboratory (RAL) will accelerate a 60 mA, 2 ms, 50 pps H⁻ beam to 3MeV. The aim of FETS is to demonstrate perfect chopping using a novel 2 stage (fast / slow) chopper scheme. The beam chopper and associated beam dumps are located in the MEBT. Achieving a low emittance-growth under the influence of strong, non-linear space-charge forces in a lattice which has to accommodate the long chopping elements is challenging. The baseline FETS MEBT design is 4.3 m long and contains 7 quadrupoles, 3 rebunching cavities, a fast and slow chopper deflector and two beam dumps. In particle dynamics simulations using a distribution from an RFQ simulation as input, beam loss for the un-chopped beam is below 1% while the chopping efficiency is >99 % in both choppers. The final MEBT lattice chosen for FETS will be presented together with particle tracking results and design details of the beam line components.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO072

Export •

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

THPME073

Performance of the Low Energy Beam Transport at the RAL Front End Test Stand

3406

J.J. Back
University of Warwick, Coventry, United Kingdom
D.C. Faircloth, A.P. Letchford
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
S.R. Lawrie
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) 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 Radio Frequency Quadrupole (RFQ). We present the current performance of the LEBT with regards to beam alignment, transmission and focusing into the acceptance of the RFQ.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME073

Export •

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

THPME186

Development of a BPM System using a Commercial FPGA Card and Digitizer Adaptor Module for FETS

3716

G.E. Boorman, S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
R.T.P. D'Arcy, S. Jolly
UCL, London, United Kingdom
S.R. Lawrie, A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

A series of beam position monitors (BPMs) will be installed at the Front End Test Stand (FETS) at RAL as part of the 3 MeV Medium Energy Beam Transport (MEBT). The BPMs analyse 2 ms long, 60 mA beam pulses delivered to the MEBT by a 324 MHz Radio Frequency Quadrupole (RFQ). Initial linearity and resolution measurements from the prototype button BPMs are shown. The development of the algorithm for the processing of the BPM signals using a commercial PXI-based FPGA card is discussed and initial measurements of the electronics and signal processing are presented. The test-rig used to characterise each BPM and further develop the processing algorithm is described. The position and phase are measured several times throughout the duration of each pulse, and the measurements are made available via an EPICS server.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME186

Export •

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

THPME191

Simulation Results of the FETS Laserwire Emittance Scanner

3729

K.O. Kruchinin, A. Bosco, S.M. Gibson, P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
D.C. Faircloth
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
S.R. Lawrie
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The Front End Test Stand (FETS) at Rutherford Appleton Laboratory (RAL) has been developed to demonstrate a high current (60 mA) H⁻ beam with the energy of 3 MeV that will be required for future proton drivers. At such high power beam machine a non-invasive diagnostics is required. To measure the emittance of the ion beam a laserwire scanner is being developed. A high power laser will scan across the H⁻ ion beam. The H⁻ particles will be neutralized via a photo-detachment process producing a stream of fast neutral hydrogen atoms bearing information about the phase space distribution of the initial H⁻ beam. To design an effective detection system and optimize its parameters a simulation of the processes at the interaction point is required. We present recent simulation results of theц FETS laserwire system. Simulations were performed using measured data of the laser propagation and ion beam distribution, obtained with General Particle Tracer code.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME191

Export •

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