IPAC2018 - List of Authors (Williams, P.H.)

Paper	Title	Page
THPMK059	Commissioning of Front End of CLARA Facility at Daresbury Laboratory	4426
	D. Angal-Kalinin, A.D. Brynes, R.K. Buckley, S.R. Buckley, J.A. Clarke, L.S. Cowie, K.D. Dumbell, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, S.A. Griffiths, F. Jackson, S.P. Jamison, J.K. Jones, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, T.C.Q. Noakes, T.J. Price, M.D. Roper, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, R.J. Smith, E.W. Snedden, N. Thompson, C. Tollervey, R. Valizadeh, D.A. Walsh, T.M. Weston, A.E. Wheelhouse, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom A.D. Brynes, J.A. Clarke, L.S. Cowie, K.D. Dumbell, D.J. Dunning, P. Goudket, F. Jackson, S.P. Jamison, J.K. Jones, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom R.J. Cash, R.F. Clarke, G. Cox, G.P. Diakun, A. Gallagher, K.D. Gleave, M.D. Hancock, J.P. Hindley, C. Hodgkinson, A. Oates, J.T.G. Wilson STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	CLARA (Compact Linear Accelerator for Research and Applications) is a Free Electron Laser (FEL) test facility being developed at STFC Daresbury Laboratory. The principal aim of CLARA is to test advanced FEL schemes which can later be implemented on existing and future short wavelength FELs. The installation of the Front End (FE) section of CLARA, a S-bend merging with existing VELA (Versatile Electron Linear Accelerator) beam line and installation of a high repetition rate RF gun on VELA was completed in 2017. First beam commissioning results and high level software developments are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK059
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THPMK060	Start-to-End Simulations of the CLARA FEL Test Facility	4430
	D.J. Dunning, D. Angal-Kalinin, A.D. Brynes, L.T. Campbell, H.M. Castaneda Cortes, J.K. Jones, J.W. McKenzie, N. Thompson, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom D. Angal-Kalinin, A.D. Brynes, D.J. Dunning, J.K. Jones, J.W. McKenzie, B.W.J. MᶜNeil, N. Thompson, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom L.T. Campbell, B.W.J. MᶜNeil, P.T. Traczykowski USTRAT/SUPA, Glasgow, United Kingdom B.S. Kyle University of Manchester, Manchester, United Kingdom B.S. Kyle UMAN, Manchester, United Kingdom J.D.A. Smith TXUK, Warrington, United Kingdom
	CLARA is a new FEL test facility being developed at STFC Daresbury Laboratory in the UK, aiming to deliver advanced FEL capabilities including few-cycle pulse generation and Fourier transform limited output. Commissioning is underway on the front-end (photo-injector and first linac) while the later stages are being procured and assembled. Start-to-end (S2E) simulations of the full facility are presented, including optimisation of the accelerator setup to deliver the required properties of one of the electron beam modes specified for FEL operation. FEL simulations are performed using the Genesis 1.3 and Puffin codes and the results are compared.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK060
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THPMK105	PERLE - Lattice Design and Beam Dynamics Studies	4556
	S.A. Bogacz, D. Douglas, F.E. Hannon, A. Hutton, F. Marhauser, R.A. Rimmer, Y. Roblin, C. Tennant JLab, Newport News, Virginia, USA D. Angal-Kalinin, J.W. McKenzie, B.L. Militsyn, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom G. Arduini, O.S. Brüning, R. Calaga, K.M. Dr. Schirm, F. Gerigk, B.J. Holzer, E. Jensen, A. Milanese, E. Montesinos, D. Pellegrini, P.A. Thonet, A. Valloni CERN, Geneva, Switzerland S. Bousson, D. Longuevergne, G. Olivier, G. Olry IPN, Orsay, France I. Chaikovska, W. Kaabi, A. Stocchi, C. Vallerand LAL, Orsay, France B. Hounsell, M. Klein, U.K. Klein, P. Kostka, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom E.B. Levichev, Yu.A. Pupkov BINP SB RAS, Novosibirsk, Russia
	Funding: Work has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy. PERLE (Powerful ERL for Experiments) is a novel ERL test facility, initially proposed to validate choices for a 60 GeV ERL foreseen in the design of the LHeC and the FCC-eh. Its main thrust is to probe high current, CW, multi-pass operation with superconducting cavities at 802 MHz (and perhaps testing other frequencies of interest). With very high virtual beam power (~ 10 MW), PERLE offers an opportunity for controllable study of every beam dynamic effect of interest in the next generation of ERL design; becoming a ‘stepping stone' between present state-of-art 1 MW ERLs and future 100 MW scale applications. PERLE design features Flexible Momentum Compaction lattice architecture for six vertically stacked return arcs and a high-current, 6 MeV, photo-injector. With only one pair of 4 cavity cryomodules, 400 MeV beam energy can be reached in 3 re-circulation passes, with beam currents in excess of 15 mA. The beam is decelerated in 3 consecutive passes back to the injection energy, transferring virtually stored energy back to the RF. This unique facility will serve as a test-bed for high current ERL technologies, as well as a user facility in low energy electron and photon physics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK105
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WEYGBE2	Applications of Caustic Methods to Longitudinal Phase Space Manipulation	1790
	T.K. Charles The University of Melbourne, Melbourne, Victoria, Australia T.K. Charles CERN, Geneva, Switzerland D. Douglas JLab, Newport News, Virginia, USA P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Longitudinal phase space management is a key feature of recirculating machines. Careful consideration of the longitudinal matching is required not only in order to ensure a high peak current, low energy spread bunch is delivered to the FEL but also to support the deceleration and energy recovery of the spent beam. In a similar manner, longitudinal phase space manipulation can be utilised for pulse shaping in bunch compression, to minimise the influence of CSR-induced emittance growth. In this paper, we present a method for longitudinal phase space matching based upon the avoidance of electron trajectory caustics. Through considering the conditions under which caustics will form, we generate exclusion plots identifying the viable parameter space at numerous positions through beam acceleration and energy recovery. The result is a method for selecting the linear momentum compaction and the higher-order momentum compaction to satisfy the non-caustic condition whilst achieving the bunch compression or lengthening as required.
	Slides WEYGBE2 [6.292 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEYGBE2
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THPAK078	GPT-CSR: a New Simulation Code for CSR Effects	3414
	S.B. van der Geer, M.J. de Loos Pulsar Physics, Eindhoven, The Netherlands A.D. Brynes, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom I.D. Setija, P.W. Smorenburg ASML Netherlands B.V., Veldhoven, The Netherlands
	For future applications of high-brightness electron beams, including the design of next generation FEL's, correct simulation of Coherent Synchrotron Radiation (CSR) is essential as it potentially degrades beam quality to unacceptable levels. However, the long interaction lengths compared to the bunch length, numerical cancellation, and difficult 3D retardation conditions make accurate simulation of CSR effects notoriously difficult. To ease the computational burden, CSR codes often make severe simplifications such as an ultra-relativistic bunch travelling on a prescribed reference trajectory. Here we report on a new CSR model implemented in the General Particle Tracer (GPT) code that avoids most of the usual assumptions: It directly evaluates the Liénard'Wiechert potentials based on the stored history of the beam. It makes no assumptions about reference trajectories, and also takes into account the transverse size of the beam. Example results demonstrating normalised emittance growth in the first bunch compressor of FERMI@Elettra are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK078
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THPAK140	Pyroelectric Detection of Coherent Radiation on the CLARA Phase 1 Beamline	3577
SUSPF077	use link to see paper's listing under its alternate paper code
	B.S. Kyle University of Manchester, Manchester, United Kingdom R.B. Appleby, T.H. Pacey UMAN, Manchester, United Kingdom P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom J. Wolfenden The University of Liverpool, Liverpool, United Kingdom
	The impacts of coherent synchrotron radiation (CSR) and space charge in the bunch compressor section of the CLARA Free Electron Laser (FEL) are expected to be significant, given the relatively high charge and short bunch lengths expected. The General Particle Tracer (GPT) code allows for the modelling of these effects in tandem, presenting an opportunity to more reliably estimate their effects on the CLARA beam. To provide confidence in future studies using GPT, a benchmarking study on the CLARA Phase 1 beamline is presented alongside relevant simulations. This study will make use of pyroelectric detectors to measure the emitted coherent power of the CLARA beam as it passes through a dispersive section whilst varying the chirp imparted on the bunches longitudinal phase space (LPS). Simulations presented demonstrate the viability of such a study, with energies between ∼ 10-100 nJ per pulse expected to be incident upon the detector face.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK140
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THPAL084	An X-Band Lineariser for the CLARA FEL	3848
	L.S. Cowie, A.D. Brynes, J.K. Jones, A.E. Wheelhouse, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom R. Apsimon, G. Burt, W.L. Millar Cockcroft Institute, Lancaster University, Lancaster, United Kingdom Ö. Mete UMAN, Manchester, United Kingdom A.J. Moss STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	The CLARA FEL at Daresbury Laboratory will employ four S-band linacs to accelerate electron bunches to 250 MeV/c. In order to compress the bunch sufficiently to achieve peak currents suitable for FEL lasing, one must compensate for curvature imprinted on the longitudinal phase space of the bunch. For CLARA a harmonic RF linearization system has been designed to achieve this requirement. The linearization will be achieved by an X-band travelling wave cavity of the PSI/CERN design, which incorporates wake-field monitoring of the bunch position. A five-axis mover will align the cavity to the beam axis. Pulse compression of a 6 MW klystron pulse will provide the required power to achieve a 30 MV/m operational gradient.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL084
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THPMK106	Architectural Considerations for Recirculated and Energy-Recovered Hard XFEL Drivers	4560
	D. Douglas, S.V. Benson, T. Powers, Y. Roblin, T. Satogata, C. Tennant JLab, Newport News, Virginia, USA D. Angal-Kalinin, N. Thompson, A.E. Wheelhouse, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom T.K. Charles CERN, Geneva, Switzerland R.C. York FRIB, East Lansing, Michigan, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. A confluence of events motivates discussion of design options for hard XFEL driver accelerators. Firstly, multiple superconducting radio-frequency (SRF) driven systems are now online (European XFEL), in construction (LCLS-II), or in design (MARIE); these provide increasing evidence of the transformational potential they offer for fundamental science with its concomitant benefits. Secondly, operation of 12 GeV CEBAF* validates use of recirculation in high energy SRF linacs. Thirdly, advances in the analysis and control of effects such as coherent synchrotron radiation (CSR) and the microbunching instability (uBI) have been recently achieved. Collectively, these developments offer insights providing extended facility science reach, reduced costs, multiplicity (i.e., support of numerous FELs operating over a range of wavelengths), and enhanced scalability and upgradability (to higher powers and energies). We will discuss the relationship amongst the various threads, and indicate how they inform design choices for the system architecture of an option for the UK-XFEL** - that of a staged multi-user X-ray FEL and nuclear physics facility based on a multi-pass recirculating SRF CW linac. M. Spata, "12 GeV CEBAF Initial Operations and Challenges", these proceedings. *P. Williams et al., Proc. FLS2018, Shanghai, China (March 2018).
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THPML060	Virtual VELA-CLARA: The Development of a Virtual Accelerator	4773
	T.J. Price, H.M. Castaneda Cortes, D.J. Dunning, J.K. Jones, B.D. Muratori, D.J. Scott, B.J.A. Shepherd, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom R.F. Clarke, G. Cox STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	A Virtual Accelerator (VA) has been developed to mimic the accelerators Versatile Electron Linear Accelerator (VELA) and Compact Linear Accelerator for Research and Applications (CLARA). Its purpose is to test control room applications, run start-to-end simulations with multiple simulation codes, accurately reproduce measured beam properties, conduct 'virtual experiments'and gain insight into ‘hidden beam parameters'. This paper gives an overview into the current progress in constructing this VA, detailing the areas of: developing a 'Virtual EPICS' control system, using multiple simulation codes (both particle tracking and analytic), the development of a ‘Master Lattice' and the construction of a Python interface in which to run the VA.
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Paper

Title

Page

Commissioning of Front End of CLARA Facility at Daresbury Laboratory

4426

D. Angal-Kalinin, A.D. Brynes, R.K. Buckley, S.R. Buckley, J.A. Clarke, L.S. Cowie, K.D. Dumbell, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, S.A. Griffiths, F. Jackson, S.P. Jamison, J.K. Jones, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, T.C.Q. Noakes, T.J. Price, M.D. Roper, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, R.J. Smith, E.W. Snedden, N. Thompson, C. Tollervey, R. Valizadeh, D.A. Walsh, T.M. Weston, A.E. Wheelhouse, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
A.D. Brynes, J.A. Clarke, L.S. Cowie, K.D. Dumbell, D.J. Dunning, P. Goudket, F. Jackson, S.P. Jamison, J.K. Jones, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
R.J. Cash, R.F. Clarke, G. Cox, G.P. Diakun, A. Gallagher, K.D. Gleave, M.D. Hancock, J.P. Hindley, C. Hodgkinson, A. Oates, J.T.G. Wilson
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

CLARA (Compact Linear Accelerator for Research and Applications) is a Free Electron Laser (FEL) test facility being developed at STFC Daresbury Laboratory. The principal aim of CLARA is to test advanced FEL schemes which can later be implemented on existing and future short wavelength FELs. The installation of the Front End (FE) section of CLARA, a S-bend merging with existing VELA (Versatile Electron Linear Accelerator) beam line and installation of a high repetition rate RF gun on VELA was completed in 2017. First beam commissioning results and high level software developments are presented in this paper.

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THPMK060

Start-to-End Simulations of the CLARA FEL Test Facility

4430

D.J. Dunning, D. Angal-Kalinin, A.D. Brynes, L.T. Campbell, H.M. Castaneda Cortes, J.K. Jones, J.W. McKenzie, N. Thompson, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
D. Angal-Kalinin, A.D. Brynes, D.J. Dunning, J.K. Jones, J.W. McKenzie, B.W.J. MᶜNeil, N. Thompson, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
L.T. Campbell, B.W.J. MᶜNeil, P.T. Traczykowski
USTRAT/SUPA, Glasgow, United Kingdom
B.S. Kyle
University of Manchester, Manchester, United Kingdom
B.S. Kyle
UMAN, Manchester, United Kingdom
J.D.A. Smith
TXUK, Warrington, United Kingdom

CLARA is a new FEL test facility being developed at STFC Daresbury Laboratory in the UK, aiming to deliver advanced FEL capabilities including few-cycle pulse generation and Fourier transform limited output. Commissioning is underway on the front-end (photo-injector and first linac) while the later stages are being procured and assembled. Start-to-end (S2E) simulations of the full facility are presented, including optimisation of the accelerator setup to deliver the required properties of one of the electron beam modes specified for FEL operation. FEL simulations are performed using the Genesis 1.3 and Puffin codes and the results are compared.

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THPMK105

PERLE - Lattice Design and Beam Dynamics Studies

4556

S.A. Bogacz, D. Douglas, F.E. Hannon, A. Hutton, F. Marhauser, R.A. Rimmer, Y. Roblin, C. Tennant
JLab, Newport News, Virginia, USA
D. Angal-Kalinin, J.W. McKenzie, B.L. Militsyn, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
G. Arduini, O.S. Brüning, R. Calaga, K.M. Dr. Schirm, F. Gerigk, B.J. Holzer, E. Jensen, A. Milanese, E. Montesinos, D. Pellegrini, P.A. Thonet, A. Valloni
CERN, Geneva, Switzerland
S. Bousson, D. Longuevergne, G. Olivier, G. Olry
IPN, Orsay, France
I. Chaikovska, W. Kaabi, A. Stocchi, C. Vallerand
LAL, Orsay, France
B. Hounsell, M. Klein, U.K. Klein, P. Kostka, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
E.B. Levichev, Yu.A. Pupkov
BINP SB RAS, Novosibirsk, Russia

Funding: Work has been authored by Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177 with the U.S. Department of Energy.
PERLE (Powerful ERL for Experiments) is a novel ERL test facility, initially proposed to validate choices for a 60 GeV ERL foreseen in the design of the LHeC and the FCC-eh. Its main thrust is to probe high current, CW, multi-pass operation with superconducting cavities at 802 MHz (and perhaps testing other frequencies of interest). With very high virtual beam power (~ 10 MW), PERLE offers an opportunity for controllable study of every beam dynamic effect of interest in the next generation of ERL design; becoming a ‘stepping stone' between present state-of-art 1 MW ERLs and future 100 MW scale applications. PERLE design features Flexible Momentum Compaction lattice architecture for six vertically stacked return arcs and a high-current, 6 MeV, photo-injector. With only one pair of 4 cavity cryomodules, 400 MeV beam energy can be reached in 3 re-circulation passes, with beam currents in excess of 15 mA. The beam is decelerated in 3 consecutive passes back to the injection energy, transferring virtually stored energy back to the RF. This unique facility will serve as a test-bed for high current ERL technologies, as well as a user facility in low energy electron and photon physics.

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WEYGBE2

Applications of Caustic Methods to Longitudinal Phase Space Manipulation

1790

T.K. Charles
The University of Melbourne, Melbourne, Victoria, Australia
T.K. Charles
CERN, Geneva, Switzerland
D. Douglas
JLab, Newport News, Virginia, USA
P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Longitudinal phase space management is a key feature of recirculating machines. Careful consideration of the longitudinal matching is required not only in order to ensure a high peak current, low energy spread bunch is delivered to the FEL but also to support the deceleration and energy recovery of the spent beam. In a similar manner, longitudinal phase space manipulation can be utilised for pulse shaping in bunch compression, to minimise the influence of CSR-induced emittance growth. In this paper, we present a method for longitudinal phase space matching based upon the avoidance of electron trajectory caustics. Through considering the conditions under which caustics will form, we generate exclusion plots identifying the viable parameter space at numerous positions through beam acceleration and energy recovery. The result is a method for selecting the linear momentum compaction and the higher-order momentum compaction to satisfy the non-caustic condition whilst achieving the bunch compression or lengthening as required.

Slides WEYGBE2 [6.292 MB]

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THPAK078

GPT-CSR: a New Simulation Code for CSR Effects

3414

S.B. van der Geer, M.J. de Loos
Pulsar Physics, Eindhoven, The Netherlands
A.D. Brynes, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
I.D. Setija, P.W. Smorenburg
ASML Netherlands B.V., Veldhoven, The Netherlands

For future applications of high-brightness electron beams, including the design of next generation FEL's, correct simulation of Coherent Synchrotron Radiation (CSR) is essential as it potentially degrades beam quality to unacceptable levels. However, the long interaction lengths compared to the bunch length, numerical cancellation, and difficult 3D retardation conditions make accurate simulation of CSR effects notoriously difficult. To ease the computational burden, CSR codes often make severe simplifications such as an ultra-relativistic bunch travelling on a prescribed reference trajectory. Here we report on a new CSR model implemented in the General Particle Tracer (GPT) code that avoids most of the usual assumptions: It directly evaluates the Liénard'Wiechert potentials based on the stored history of the beam. It makes no assumptions about reference trajectories, and also takes into account the transverse size of the beam. Example results demonstrating normalised emittance growth in the first bunch compressor of FERMI@Elettra are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK078

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THPAK140

Pyroelectric Detection of Coherent Radiation on the CLARA Phase 1 Beamline

3577

SUSPF077

use link to see paper's listing under its alternate paper code

B.S. Kyle
University of Manchester, Manchester, United Kingdom
R.B. Appleby, T.H. Pacey
UMAN, Manchester, United Kingdom
P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J. Wolfenden
The University of Liverpool, Liverpool, United Kingdom

The impacts of coherent synchrotron radiation (CSR) and space charge in the bunch compressor section of the CLARA Free Electron Laser (FEL) are expected to be significant, given the relatively high charge and short bunch lengths expected. The General Particle Tracer (GPT) code allows for the modelling of these effects in tandem, presenting an opportunity to more reliably estimate their effects on the CLARA beam. To provide confidence in future studies using GPT, a benchmarking study on the CLARA Phase 1 beamline is presented alongside relevant simulations. This study will make use of pyroelectric detectors to measure the emitted coherent power of the CLARA beam as it passes through a dispersive section whilst varying the chirp imparted on the bunches longitudinal phase space (LPS). Simulations presented demonstrate the viability of such a study, with energies between ∼ 10-100 nJ per pulse expected to be incident upon the detector face.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK140

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THPAL084

An X-Band Lineariser for the CLARA FEL

3848

L.S. Cowie, A.D. Brynes, J.K. Jones, A.E. Wheelhouse, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R. Apsimon, G. Burt, W.L. Millar
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
Ö. Mete
UMAN, Manchester, United Kingdom
A.J. Moss
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

The CLARA FEL at Daresbury Laboratory will employ four S-band linacs to accelerate electron bunches to 250 MeV/c. In order to compress the bunch sufficiently to achieve peak currents suitable for FEL lasing, one must compensate for curvature imprinted on the longitudinal phase space of the bunch. For CLARA a harmonic RF linearization system has been designed to achieve this requirement. The linearization will be achieved by an X-band travelling wave cavity of the PSI/CERN design, which incorporates wake-field monitoring of the bunch position. A five-axis mover will align the cavity to the beam axis. Pulse compression of a 6 MW klystron pulse will provide the required power to achieve a 30 MV/m operational gradient.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL084

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THPMK106

Architectural Considerations for Recirculated and Energy-Recovered Hard XFEL Drivers

4560

D. Douglas, S.V. Benson, T. Powers, Y. Roblin, T. Satogata, C. Tennant
JLab, Newport News, Virginia, USA
D. Angal-Kalinin, N. Thompson, A.E. Wheelhouse, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
T.K. Charles
CERN, Geneva, Switzerland
R.C. York
FRIB, East Lansing, Michigan, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A confluence of events motivates discussion of design options for hard XFEL driver accelerators. Firstly, multiple superconducting radio-frequency (SRF) driven systems are now online (European XFEL), in construction (LCLS-II), or in design (MARIE); these provide increasing evidence of the transformational potential they offer for fundamental science with its concomitant benefits. Secondly, operation of 12 GeV CEBAF* validates use of recirculation in high energy SRF linacs. Thirdly, advances in the analysis and control of effects such as coherent synchrotron radiation (CSR) and the microbunching instability (uBI) have been recently achieved. Collectively, these developments offer insights providing extended facility science reach, reduced costs, multiplicity (i.e., support of numerous FELs operating over a range of wavelengths), and enhanced scalability and upgradability (to higher powers and energies). We will discuss the relationship amongst the various threads, and indicate how they inform design choices for the system architecture of an option for the UK-XFEL** - that of a staged multi-user X-ray FEL and nuclear physics facility based on a multi-pass recirculating SRF CW linac.
*M. Spata, "12 GeV CEBAF Initial Operations and Challenges", these proceedings.
**P. Williams et al., Proc. FLS2018, Shanghai, China (March 2018).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK106

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THPML060

Virtual VELA-CLARA: The Development of a Virtual Accelerator

4773

T.J. Price, H.M. Castaneda Cortes, D.J. Dunning, J.K. Jones, B.D. Muratori, D.J. Scott, B.J.A. Shepherd, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R.F. Clarke, G. Cox
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

A Virtual Accelerator (VA) has been developed to mimic the accelerators Versatile Electron Linear Accelerator (VELA) and Compact Linear Accelerator for Research and Applications (CLARA). Its purpose is to test control room applications, run start-to-end simulations with multiple simulation codes, accurately reproduce measured beam properties, conduct 'virtual experiments'and gain insight into ‘hidden beam parameters'. This paper gives an overview into the current progress in constructing this VA, detailing the areas of: developing a 'Virtual EPICS' control system, using multiple simulation codes (both particle tracking and analytic), the development of a ‘Master Lattice' and the construction of a Python interface in which to run the VA.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML060

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