FEL2015 - List of Authors (Spampinati, S.)

Paper	Title	Page
MOC03	Estimate of Free-Electron Laser Gain Length in the Presence of Electron Beam Collective Effects	24
	S. Di Mitri Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy S. Spampinati Cockcroft Institute, Warrington, Cheshire, United Kingdom
	A novel definition for the three-dimensional free electron laser gain length is proposed, which takes into account the increase of electron beam projected emittance as due, for example, to geometric transverse wakefield and coherent synchrotron radiation developing in linear accelerators. The analysis shows that the gain length is affected by an increase of the electron beam projected emittance, even though the slice (local) emittance is preserved, and found to be in agreement with Genesis code simulation results. It is then shown that the minimum gain length and the maximum of output power may notably differ from the ones derived when collective effects are neglected. The proposed model turns out to be handy for a parametric study of electron beam six-dimensional brightness and FEL performance as function, e.g., of bunch length compression factor, accelerator alignment tolerances and optics design. S. Di Mitri, S. Spampinati, Phys. Rev. Special Topics Accel. Beams, 17, 110702 (2014)
	Slides MOC03 [2.528 MB]
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MOP011	Status of CLARA, a New FEL Test Facility	49
	J.A. Clarke, D. Angal-Kalinin, A.D. Brynes, R.K. Buckley, S.R. Buckley, L.S. Cowie, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, P.C. Hornickel, F. Jackson, S.P. Jamison, J.K. Jones, K.B. Marinov, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, M.D. Roper, L.K. Rudge, Y.M. Saveliev, B.J.A. Shepherd, R.J. Smith, S.L. Smith, E.W. Snedden, M. Surman, T.T. Thakker, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom R.B. Appleby, K. Hanahoe, O. Mete Apsimon, H.L. Owen, G.X. Xia UMAN, Manchester, United Kingdom P. Atkinson, N. Bliss, R.J. Cash, N.A. Collomb, G. Cox, G.P. Diakun, S. Dobson, A. Gallagher, S.A. Griffiths, C. Hill, C. Hodgkinson, D.M.P. Holland, T.J. Jones, B.G. Martlew, J. Williams STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom R. Bartolini, I.P.S. Martin DLS, Oxfordshire, United Kingdom S.T. Boogert, E. Yamakawa Royal Holloway, University of London, Surrey, United Kingdom G. Burt, P.N. Ratoff Lancaster University, Lancaster, United Kingdom L.T. Campbell, A.J.T. Colin, J. Henderson, B. Hidding, B.W.J. MᶜNeil USTRAT/SUPA, Glasgow, United Kingdom A.M. Kolano University of Huddersfield, Huddersfield, United Kingdom A. Lyapin JAI, Egham, Surrey, United Kingdom V.V. Paramonov, A.K. Skasyrskaya RAS/INR, Moscow, Russia J.D.A. Smith TXUK, Warrington, United Kingdom S. Spampinati Cockcroft Institute, Warrington, Cheshire, United Kingdom Y. Wei, C.P. Welsch, A. Wolski The University of Liverpool, Liverpool, United Kingdom
	CLARA is a new FEL test facility being developed at STFC Daresbury Laboratory in the UK. The main motivation for CLARA is to test new FEL schemes that can later be implemented on existing and future short wavelength FELs. Particular focus will be on ultra-short pulse generation, pulse stability, and synchronisation with external sources. The project is now underway and the Front End section (photoinjector and first linac) installation will begin later this year. This paper will discuss the progress with the Front End assembly and also highlighting other topics which are currently receiving significant attention.
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MOP044	A Laser Heater for CLARA	129
	S. Spampinati Cockcroft Institute, Warrington, Cheshire, United Kingdom B.D. Muratori, N. Thompson, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	CLARA is a new FEL test facility, being developed at STFC Daresbury Laboratory in UK, based on a high brightness electron linac. The electron beam of CLARA can potentially be affected by the longitudinal microbunching instability leading to a degradation of the beam quality. The inclusion of a laser heater in the linac design can allow control of the microbunching instability, the study of microbunching and deliberate increase of the final energy spread to study energy spread requirements of the FEL schemes tested at CLARA. We present the initial design and layout of the laser heater system for CLARA and its expected performance.
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MOP067	Transverse Emittance-Preserving Transfer Line and Arc Compressor for High Brightness Electron Sources	191
	S. Di Mitri, M. Cornacchia, S. Spampinati Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy S. Spampinati Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Minimizing transverse emittance is essential in single- or few-passes accelerators designed to deliver high brightness electron beams. Emission of coherent synchrotron radiation (CSR) is an important factor of emittance degradation. We have demonstrated, with analytical and experimental results, that this perturbation may be cancelled by imposing certain conditions on the electron optics when the bunch length is constant along the line. This scheme of CSR suppression is then enlarged, analytically and numerically, to cover the case of varying bunch length in a periodic arc compressor. The proposed solution hold the promise of cost-saving of compact transfer lines with large bending angles, and new schemes for beam longitudinal gymnastics both in recirculating and in single-pass accelerators driving free electron lasers. S. Di Mitri, M. Cornacchia, S. Spampinati, Phys. Rev. Letters, 110, 014801 (2013) ** S. Di Mitri, M. Cornacchia, Europhys. Letters, 109, 62002 (2015)
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WEP048	Electron Beam Diagnostics for FEL Studies at CLARA	672
	S. Spampinati Cockcroft Institute, Warrington, Cheshire, United Kingdom D. Newton The University of Liverpool, Liverpool, United Kingdom
	CLARA (Compact Linear Accelerator for Research and Applications) is a proposed 250 MeV, 100-400 nm FEL test facility at Daresbury Laboratory [1]. The purpose of CLARA is to test and validate new FEL schemes in areas such as ultra-short pulse generation, temporal coherence and pulse-tailoring. Some of the schemes that can be tested at CLARA depend on a manipulation of the electron beam properties with characteristic scales shorter than the electron beam. In this article we describe the electron beam diagnostics required to carry on these experiments and simulations of FEL pulse and electron beam measurements. [1] J. A. Clarke et al., JINST 9, 05 (2014).
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Paper

Title

Page

Estimate of Free-Electron Laser Gain Length in the Presence of Electron Beam Collective Effects

24

S. Di Mitri
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
S. Spampinati
Cockcroft Institute, Warrington, Cheshire, United Kingdom

A novel definition for the three-dimensional free electron laser gain length is proposed*, which takes into account the increase of electron beam projected emittance as due, for example, to geometric transverse wakefield and coherent synchrotron radiation developing in linear accelerators. The analysis shows that the gain length is affected by an increase of the electron beam projected emittance, even though the slice (local) emittance is preserved, and found to be in agreement with Genesis code simulation results. It is then shown that the minimum gain length and the maximum of output power may notably differ from the ones derived when collective effects are neglected. The proposed model turns out to be handy for a parametric study of electron beam six-dimensional brightness and FEL performance as function, e.g., of bunch length compression factor, accelerator alignment tolerances and optics design.
* S. Di Mitri, S. Spampinati, Phys. Rev. Special Topics Accel. Beams, 17, 110702 (2014)

Slides MOC03 [2.528 MB]

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MOP011

Status of CLARA, a New FEL Test Facility

49

J.A. Clarke, D. Angal-Kalinin, A.D. Brynes, R.K. Buckley, S.R. Buckley, L.S. Cowie, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, P.C. Hornickel, F. Jackson, S.P. Jamison, J.K. Jones, K.B. Marinov, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, M.D. Roper, L.K. Rudge, Y.M. Saveliev, B.J.A. Shepherd, R.J. Smith, S.L. Smith, E.W. Snedden, M. Surman, T.T. Thakker, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R.B. Appleby, K. Hanahoe, O. Mete Apsimon, H.L. Owen, G.X. Xia
UMAN, Manchester, United Kingdom
P. Atkinson, N. Bliss, R.J. Cash, N.A. Collomb, G. Cox, G.P. Diakun, S. Dobson, A. Gallagher, S.A. Griffiths, C. Hill, C. Hodgkinson, D.M.P. Holland, T.J. Jones, B.G. Martlew, J. Williams
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
R. Bartolini, I.P.S. Martin
DLS, Oxfordshire, United Kingdom
S.T. Boogert, E. Yamakawa
Royal Holloway, University of London, Surrey, United Kingdom
G. Burt, P.N. Ratoff
Lancaster University, Lancaster, United Kingdom
L.T. Campbell, A.J.T. Colin, J. Henderson, B. Hidding, B.W.J. MᶜNeil
USTRAT/SUPA, Glasgow, United Kingdom
A.M. Kolano
University of Huddersfield, Huddersfield, United Kingdom
A. Lyapin
JAI, Egham, Surrey, United Kingdom
V.V. Paramonov, A.K. Skasyrskaya
RAS/INR, Moscow, Russia
J.D.A. Smith
TXUK, Warrington, United Kingdom
S. Spampinati
Cockcroft Institute, Warrington, Cheshire, United Kingdom
Y. Wei, C.P. Welsch, A. Wolski
The University of Liverpool, Liverpool, United Kingdom

CLARA is a new FEL test facility being developed at STFC Daresbury Laboratory in the UK. The main motivation for CLARA is to test new FEL schemes that can later be implemented on existing and future short wavelength FELs. Particular focus will be on ultra-short pulse generation, pulse stability, and synchronisation with external sources. The project is now underway and the Front End section (photoinjector and first linac) installation will begin later this year. This paper will discuss the progress with the Front End assembly and also highlighting other topics which are currently receiving significant attention.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOP044

A Laser Heater for CLARA

129

S. Spampinati
Cockcroft Institute, Warrington, Cheshire, United Kingdom
B.D. Muratori, N. Thompson, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

CLARA is a new FEL test facility, being developed at STFC Daresbury Laboratory in UK, based on a high brightness electron linac. The electron beam of CLARA can potentially be affected by the longitudinal microbunching instability leading to a degradation of the beam quality. The inclusion of a laser heater in the linac design can allow control of the microbunching instability, the study of microbunching and deliberate increase of the final energy spread to study energy spread requirements of the FEL schemes tested at CLARA. We present the initial design and layout of the laser heater system for CLARA and its expected performance.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOP067

Transverse Emittance-Preserving Transfer Line and Arc Compressor for High Brightness Electron Sources

191

S. Di Mitri, M. Cornacchia, S. Spampinati
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
S. Spampinati
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Minimizing transverse emittance is essential in single- or few-passes accelerators designed to deliver high brightness electron beams. Emission of coherent synchrotron radiation (CSR) is an important factor of emittance degradation. We have demonstrated, with analytical and experimental results, that this perturbation may be cancelled by imposing certain conditions on the electron optics when the bunch length is constant along the line*. This scheme of CSR suppression is then enlarged, analytically and numerically, to cover the case of varying bunch length in a periodic arc compressor**. The proposed solution hold the promise of cost-saving of compact transfer lines with large bending angles, and new schemes for beam longitudinal gymnastics both in recirculating and in single-pass accelerators driving free electron lasers.
* S. Di Mitri, M. Cornacchia, S. Spampinati, Phys. Rev. Letters, 110, 014801 (2013)
** S. Di Mitri, M. Cornacchia, Europhys. Letters, 109, 62002 (2015)

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WEP048

Electron Beam Diagnostics for FEL Studies at CLARA

672

S. Spampinati
Cockcroft Institute, Warrington, Cheshire, United Kingdom
D. Newton
The University of Liverpool, Liverpool, United Kingdom

CLARA (Compact Linear Accelerator for Research and Applications) is a proposed 250 MeV, 100-400 nm FEL test facility at Daresbury Laboratory [1]. The purpose of CLARA is to test and validate new FEL schemes in areas such as ultra-short pulse generation, temporal coherence and pulse-tailoring. Some of the schemes that can be tested at CLARA depend on a manipulation of the electron beam properties with characteristic scales shorter than the electron beam. In this article we describe the electron beam diagnostics required to carry on these experiments and simulations of FEL pulse and electron beam measurements.
[1] J. A. Clarke et al., JINST 9, 05 (2014).

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