IPAC2013 - List of Authors (D'Arcy, R.T.P.)

Paper	Title	Page
TUPWO055	Phase Rotation Experiment at EMMA for testing Applicability of a Non-scaling FFAG for PRISM System	1991
	B.D. Muratori, J.K. Jones STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom R.T.P. D'Arcy UCL, London, United Kingdom J.K. Jones, B.D. Muratori Cockcroft Institute, Warrington, Cheshire, United Kingdom D.J. Kelliher, S. Machida STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom H.L. Owen UMAN, Manchester, United Kingdom J. Pasternak STFC/RAL, Chilton, Didcot, Oxon, United Kingdom J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	EMMA is the world’s 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 performing RF phase rotation in an FFAG ring. Current baseline design for PRISM applies the scaling FFAG ring, but an alternative machine could be based on a ns-FFAG principle. As the transverse-longitudinal coupling is present in ns-FFAGs due to a natural chromaticity, its effect on the final energy spread and beam quality needs to be tested. In order to gauge the expected results, an experiment was designed to be performed on EMMA. We report here the details of this experiment and the results gathered from EMMA operation.

TUPWO056	Modelling of the EMMA ns-FFAG Ring using GPT	1994
	R.T.P. D'Arcy UCL, London, United Kingdom J.K. Jones, B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands
	EMMA (Electron Machine with Many Applications) is a prototype non-scaling Fixed-Field Alternating Gradient (ns-FFAG) accelerator whose construction at Daresbury Laboratory, UK, was completed in the autumn of 2010. The energy recovery linac ALICE serves as an injector for the EMMA ring, within an effective energy range of 10 to 20 MeV. The ring is composed of 42 cells, each containing one focusing and one defocusing quadrupole. Acceleration over many turns of the EMMA machine has recently been confirmed. In some cases the bunch will traverse upwards of 100 turns, at which point the effects of space-charge may be significant. It is therefore necessary to model the electron beam transport in the ring using a code capable of both calculating the effect of and compensating for space-charge. Therefore the General Particle Tracer (GPT) code has been used. A range of injection beam parameters have been modelled for comparison with experimental results and those of other codes. The simulated effects of space-charge on the tune shift of the machine are also compared with those expected from theory.

WEPEA074	Optimisation of the Beam Line for COMET Phase-I	2681
	A. Kurup, I. Puri, Y. Uchida, Y. Yap Imperial College of Science and Technology, Department of Physics, London, United Kingdom R. Appleby, S.C. Tygier UMAN, Manchester, United Kingdom R.T.P. D'Arcy, A. Edmonds, M. Lancaster, M. Wing UCL, London, United Kingdom
	The COMET experiment will search for very rare muon processes that will give us an insight into particle physics beyond the Standard Model. COMET requires an intense beam of muons with a momentum less than 70 MeV/c. This is achieved using an 8 GeV proton beam; a heavy metal target to primarily produce pions; a solenoid capture system; and a curved solenoid to perform charge and momentum selection. It was recently proposed to build COMET is two phases with physics measurements being made in both phases. This requires re-optimising the beam line for a shorter curved solenoid. This will affect the pion and muon yield; the momentum distributions at the detector; and the collimator scheme required. This paper will present the beam line design for COMET Phase-I, which aims to maximise the yield for low momentum muons suppressing sources of backgrounds in the beam.

WEPEA075	Large Emittance Beam Measurements for COMET Phase-I	2684
	A. Kurup, I. Puri, Y. Uchida, Y. Yap Imperial College of Science and Technology, Department of Physics, London, United Kingdom R. Appleby, S.C. Tygier UMAN, Manchester, United Kingdom R.T.P. D'Arcy, A. Edmonds, M. Lancaster, M. Wing UCL, London, United Kingdom
	The COMET experiment will search for very rare muon processes that will give us an insight into particle physics beyond the Standard Model. COMET requires an intense beam of muons with a momentum less than 70 MeV/c. This is achieved using an 8 GeV proton beam; a heavy metal target to primarily produce pions; a solenoid capture system; and a curved solenoid to perform charge and momentum selection. Understanding the pion production yield and transport properties of the beam line is an important part of the experiment. The beam line is a continuous solenoid channel, so it is only possible to place a beam diagnostic device at the end of the beam line. Building COMET in two phases provides the opportunity to investigate the pion production yield and to measure the transport properties of the beam line in Phase-I. This paper will demonstrate how this will be done using the experimental set up for COMET Phase-I.

THPWA041	Acceptance and Transmission Simulations of the FETS RFQ	3720
	S. Jolly, R.T.P. D'Arcy UCL, London, United Kingdom A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski Imperial College of Science and Technology, Department of Physics, London, United Kingdom J.K. Pozimski STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
	A 4m-long, 324MHz four-vane RFQ, consisting of four coupled sections, has been 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, was used to optimise the design of the RFQ. With the design of the RFQ fixed, the focus has been on optimising the transmission of the RFQ at 3 MeV and matching the output of the FETS Low Energy Beam Transport (LEBT) to the RFQ acceptance. Extensive simulations have been carried out using General Particle Tracer (GPT) to map out the acceptance of the FETS RFQ for a 65 keV H⁻ input beam. Particular attention has focussed on optimising the simulations to match the optimised output of the FETS Penning-type H⁻ ion source. Results are presented of the transverse phase space limits on the RFQ input acceptance in both the zero current and full space charge regimes.

THPWO086	Status of the RAL Front End Test Stand	3963
	A.P. Letchford, M.A. Clarke-Gayther, D.C. Faircloth, S.R. Lawrie STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom S.M.H. Alsari, M. Aslaninejad, J.K. Pozimski, P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom J.J. Back University of Warwick, Coventry, United Kingdom G.E. Boorman, A. Bosco, S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom R.T.P. D'Arcy, S. Jolly UCL, London, United Kingdom C. Gabor, D.C. Plostinar STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
	The Front End Test Stand (FETS) under construction at RAL is a demonstrator for the 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 and non-destructive photo-detachment diagnostics. This paper describes the current status of the project and future plans.

Paper

Title

Page

Phase Rotation Experiment at EMMA for testing Applicability of a Non-scaling FFAG for PRISM System

1991

B.D. Muratori, J.K. Jones
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R.T.P. D'Arcy
UCL, London, United Kingdom
J.K. Jones, B.D. Muratori
Cockcroft Institute, Warrington, Cheshire, United Kingdom
D.J. Kelliher, S. Machida
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
H.L. Owen
UMAN, Manchester, United Kingdom
J. Pasternak
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

EMMA is the world’s 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 performing RF phase rotation in an FFAG ring. Current baseline design for PRISM applies the scaling FFAG ring, but an alternative machine could be based on a ns-FFAG principle. As the transverse-longitudinal coupling is present in ns-FFAGs due to a natural chromaticity, its effect on the final energy spread and beam quality needs to be tested. In order to gauge the expected results, an experiment was designed to be performed on EMMA. We report here the details of this experiment and the results gathered from EMMA operation.

TUPWO056

Modelling of the EMMA ns-FFAG Ring using GPT

1994

R.T.P. D'Arcy
UCL, London, United Kingdom
J.K. Jones, B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

EMMA (Electron Machine with Many Applications) is a prototype non-scaling Fixed-Field Alternating Gradient (ns-FFAG) accelerator whose construction at Daresbury Laboratory, UK, was completed in the autumn of 2010. The energy recovery linac ALICE serves as an injector for the EMMA ring, within an effective energy range of 10 to 20 MeV. The ring is composed of 42 cells, each containing one focusing and one defocusing quadrupole. Acceleration over many turns of the EMMA machine has recently been confirmed. In some cases the bunch will traverse upwards of 100 turns, at which point the effects of space-charge may be significant. It is therefore necessary to model the electron beam transport in the ring using a code capable of both calculating the effect of and compensating for space-charge. Therefore the General Particle Tracer (GPT) code has been used. A range of injection beam parameters have been modelled for comparison with experimental results and those of other codes. The simulated effects of space-charge on the tune shift of the machine are also compared with those expected from theory.

WEPEA074

Optimisation of the Beam Line for COMET Phase-I

2681

A. Kurup, I. Puri, Y. Uchida, Y. Yap
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
R. Appleby, S.C. Tygier
UMAN, Manchester, United Kingdom
R.T.P. D'Arcy, A. Edmonds, M. Lancaster, M. Wing
UCL, London, United Kingdom

The COMET experiment will search for very rare muon processes that will give us an insight into particle physics beyond the Standard Model. COMET requires an intense beam of muons with a momentum less than 70 MeV/c. This is achieved using an 8 GeV proton beam; a heavy metal target to primarily produce pions; a solenoid capture system; and a curved solenoid to perform charge and momentum selection. It was recently proposed to build COMET is two phases with physics measurements being made in both phases. This requires re-optimising the beam line for a shorter curved solenoid. This will affect the pion and muon yield; the momentum distributions at the detector; and the collimator scheme required. This paper will present the beam line design for COMET Phase-I, which aims to maximise the yield for low momentum muons suppressing sources of backgrounds in the beam.

WEPEA075

Large Emittance Beam Measurements for COMET Phase-I

2684

A. Kurup, I. Puri, Y. Uchida, Y. Yap
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
R. Appleby, S.C. Tygier
UMAN, Manchester, United Kingdom
R.T.P. D'Arcy, A. Edmonds, M. Lancaster, M. Wing
UCL, London, United Kingdom

The COMET experiment will search for very rare muon processes that will give us an insight into particle physics beyond the Standard Model. COMET requires an intense beam of muons with a momentum less than 70 MeV/c. This is achieved using an 8 GeV proton beam; a heavy metal target to primarily produce pions; a solenoid capture system; and a curved solenoid to perform charge and momentum selection. Understanding the pion production yield and transport properties of the beam line is an important part of the experiment. The beam line is a continuous solenoid channel, so it is only possible to place a beam diagnostic device at the end of the beam line. Building COMET in two phases provides the opportunity to investigate the pion production yield and to measure the transport properties of the beam line in Phase-I. This paper will demonstrate how this will be done using the experimental set up for COMET Phase-I.

THPWA041

Acceptance and Transmission Simulations of the FETS RFQ

3720

S. Jolly, R.T.P. D'Arcy
UCL, London, United Kingdom
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
J.K. Pozimski
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

A 4m-long, 324MHz four-vane RFQ, consisting of four coupled sections, has been 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, was used to optimise the design of the RFQ. With the design of the RFQ fixed, the focus has been on optimising the transmission of the RFQ at 3 MeV and matching the output of the FETS Low Energy Beam Transport (LEBT) to the RFQ acceptance. Extensive simulations have been carried out using General Particle Tracer (GPT) to map out the acceptance of the FETS RFQ for a 65 keV H⁻ input beam. Particular attention has focussed on optimising the simulations to match the optimised output of the FETS Penning-type H⁻ ion source. Results are presented of the transverse phase space limits on the RFQ input acceptance in both the zero current and full space charge regimes.

THPWO086

Status of the RAL Front End Test Stand

3963

A.P. Letchford, M.A. Clarke-Gayther, D.C. Faircloth, S.R. Lawrie
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
S.M.H. Alsari, M. Aslaninejad, J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
J.J. Back
University of Warwick, Coventry, United Kingdom
G.E. Boorman, A. Bosco, S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
R.T.P. D'Arcy, S. Jolly
UCL, London, United Kingdom
C. Gabor, D.C. Plostinar
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

The Front End Test Stand (FETS) under construction at RAL is a demonstrator for the 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 and non-destructive photo-detachment diagnostics. This paper describes the current status of the project and future plans.