IPAC2019 - List of Authors (Pitman, S.)

Paper	Title	Page
MOPTS054	Status of the CLEAR Electron Beam User Facility at CERN	983
	K.N. Sjobak, E. Adli, C.A. Lindstrøm University of Oslo, Oslo, Norway M. Bergamaschi, S. Burger, R. Corsini, A. Curcio, S. Curt, S. Döbert, W. Farabolini, D. Gamba, L. Garolfi, A. Gilardi, I. Gorgisyan, E. Granados, H. Guerin, R. Kieffer, M. Krupa, T. Lefèvre, S. Mazzoni, G. McMonagle, N. Nadenau, H. Panuganti, S. Pitman, V. Rude, A. Schlogelhofer, P.K. Skowroński, M. Wendt, A.P. Zemanek CERN, Geneva, Switzerland A. Lyapin UCL, London, United Kingdom
	The CERN Linear Electron Accelerator for Research (CLEAR) has now finished its second year of operation, providing a testbed for new accelerator technologies and a versatile radiation source. Hosting a varied experimental program, this beamline provides a flexible test facility for users both internal and external to CERN, as well as being an excellent accelerator physics training ground. The energy can be varied between 60 and 220 MeV, bunch length between 1 and 4 ps, bunch charge in the range 10 pC to 2 nC, and number of bunches in the range 1 to 200, at a repetition rate of 0.8 to 10 Hz. The status of the facility with an overview of the recent experimental results is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS054
About •	paper received ※ 12 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPRB059	Dark Current Analysis at CERN’s X-band Facility	2944
	D. Banon-Caballero, M. Boronat, V. Sánchez Sebastián, A. Vnuchenko IFIC, Valencia, Spain N. Catalán Lasheras, S. Pitman, M. Widorski, W. Wuensch, V. del Pozo Romano CERN, Meyrin, Switzerland A. Faus-Golfe LAL, Orsay, France B. Gimeno UVEG, Burjasot (Valencia), Spain T.G. Lucas, M. Volpi The University of Melbourne, Melbourne, Victoria, Australia W.L. Millar Lancaster University, Lancaster, United Kingdom J. Paszkiewicz University of Oxford, Oxford, United Kingdom
	Dark current is particularly relevant during operation in high-gradient linear accelerators. Resulting from the capture of field emitted electrons, dark current produces additional radiation that needs to be accounted for in experiments. In this paper, an analysis of dark current is presented for four accelerating structures that were tested and conditioned in CERN’s X-band test facility for CLIC. The dependence on power, and therefore on accelerating gradient, of the dark current signals is presented. The Fowler-Nordheim equation for field emission seems to be in accordance with the experimental data. Moreover, the analysis shows that the current intensity decreases as a function of time due to conditioning, but discrete jumps in the dark current signals are present, probably caused by breakdown events that change the emitters’ location and intensity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB059
About •	paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPRB063	Connection of 12 GHz High Power RF from the XBOX 1 High Gradient Test Stand to the CLEAR Electron LINAC	2960
	A.V. Edwards Cockcroft Institute, Lancaster University, Lancaster, United Kingdom N. Catalán Lasheras, S. Gonzalez Anton, G. McMonagle, S. Pitman, B.J. Woolley, V. del Pozo Romano CERN, Meyrin, Switzerland
	A new RF system is being established at XBOX1 to drive two §I{100}{MV/m} CLIC structures in the CLEAR electron linac. In the past, these structures had been powered by RF from PET structures excited by a drive beam. This drive beam is no longer available. The upgrade will reroute power from the §I{50}{MW} klystron and pulse compressor which was previously used to power the structure in XBOX1. During the upgrade, the LLRF system will be optimised to improve the modulation of the output signals and down-mixing of the returning signals to obtain accurate phase and amplitude information. The design of the improved LLRF and software, along with phase noise measurements and comparisons with the old system are made in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB063
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRB064	High Power Conditioning of X-Band Variable Power Splitter and Phase Shifter	2964
	V. del Pozo Romano, H. Bursali, N. Catalán Lasheras, A. Grudiev, S. Pitman, I. Syratchev CERN, Geneva, Switzerland C. Serpico Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy M. Volpi The University of Melbourne, Melbourne, Victoria, Australia
	The three X-band test facilities currently at CERN aim at qualifying CLIC structures prototypes but are also exten- sively used to qualify X-band components operation at high power. In order to upgrade one of the facilities from a single test line to a double test line facility, a high power variable splitter and variable phase shifter have been designed and manufactured at CERN. They have been power tested, ﬁrst in a dedicated test and also in their ﬁnal conﬁguration, to en- sure stable power operation before installing them together with an accelerating structure. In this paper, we broadly describe the RF and mechanical design, manufacturing and low power measurements agreement with simulations. We report the high power qualiﬁcation of both components and their suitability to be used in existing and planned X-band facilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB064
About •	paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Status of the CLEAR Electron Beam User Facility at CERN

983

K.N. Sjobak, E. Adli, C.A. Lindstrøm
University of Oslo, Oslo, Norway
M. Bergamaschi, S. Burger, R. Corsini, A. Curcio, S. Curt, S. Döbert, W. Farabolini, D. Gamba, L. Garolfi, A. Gilardi, I. Gorgisyan, E. Granados, H. Guerin, R. Kieffer, M. Krupa, T. Lefèvre, S. Mazzoni, G. McMonagle, N. Nadenau, H. Panuganti, S. Pitman, V. Rude, A. Schlogelhofer, P.K. Skowroński, M. Wendt, A.P. Zemanek
CERN, Geneva, Switzerland
A. Lyapin
UCL, London, United Kingdom

The CERN Linear Electron Accelerator for Research (CLEAR) has now finished its second year of operation, providing a testbed for new accelerator technologies and a versatile radiation source. Hosting a varied experimental program, this beamline provides a flexible test facility for users both internal and external to CERN, as well as being an excellent accelerator physics training ground. The energy can be varied between 60 and 220 MeV, bunch length between 1 and 4 ps, bunch charge in the range 10 pC to 2 nC, and number of bunches in the range 1 to 200, at a repetition rate of 0.8 to 10 Hz. The status of the facility with an overview of the recent experimental results is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS054

About •

paper received ※ 12 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

Export •

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

WEPRB059

Dark Current Analysis at CERN’s X-band Facility

2944

D. Banon-Caballero, M. Boronat, V. Sánchez Sebastián, A. Vnuchenko
IFIC, Valencia, Spain
N. Catalán Lasheras, S. Pitman, M. Widorski, W. Wuensch, V. del Pozo Romano
CERN, Meyrin, Switzerland
A. Faus-Golfe
LAL, Orsay, France
B. Gimeno
UVEG, Burjasot (Valencia), Spain
T.G. Lucas, M. Volpi
The University of Melbourne, Melbourne, Victoria, Australia
W.L. Millar
Lancaster University, Lancaster, United Kingdom
J. Paszkiewicz
University of Oxford, Oxford, United Kingdom

Dark current is particularly relevant during operation in high-gradient linear accelerators. Resulting from the capture of field emitted electrons, dark current produces additional radiation that needs to be accounted for in experiments. In this paper, an analysis of dark current is presented for four accelerating structures that were tested and conditioned in CERN’s X-band test facility for CLIC. The dependence on power, and therefore on accelerating gradient, of the dark current signals is presented. The Fowler-Nordheim equation for field emission seems to be in accordance with the experimental data. Moreover, the analysis shows that the current intensity decreases as a function of time due to conditioning, but discrete jumps in the dark current signals are present, probably caused by breakdown events that change the emitters’ location and intensity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB059

About •

paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

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

WEPRB063

Connection of 12 GHz High Power RF from the XBOX 1 High Gradient Test Stand to the CLEAR Electron LINAC

2960

A.V. Edwards
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
N. Catalán Lasheras, S. Gonzalez Anton, G. McMonagle, S. Pitman, B.J. Woolley, V. del Pozo Romano
CERN, Meyrin, Switzerland

A new RF system is being established at XBOX1 to drive two §I{100}{MV/m} CLIC structures in the CLEAR electron linac. In the past, these structures had been powered by RF from PET structures excited by a drive beam. This drive beam is no longer available. The upgrade will reroute power from the §I{50}{MW} klystron and pulse compressor which was previously used to power the structure in XBOX1. During the upgrade, the LLRF system will be optimised to improve the modulation of the output signals and down-mixing of the returning signals to obtain accurate phase and amplitude information. The design of the improved LLRF and software, along with phase noise measurements and comparisons with the old system are made in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB063

About •

paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

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

WEPRB064

High Power Conditioning of X-Band Variable Power Splitter and Phase Shifter

2964

V. del Pozo Romano, H. Bursali, N. Catalán Lasheras, A. Grudiev, S. Pitman, I. Syratchev
CERN, Geneva, Switzerland
C. Serpico
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
M. Volpi
The University of Melbourne, Melbourne, Victoria, Australia

The three X-band test facilities currently at CERN aim at qualifying CLIC structures prototypes but are also exten- sively used to qualify X-band components operation at high power. In order to upgrade one of the facilities from a single test line to a double test line facility, a high power variable splitter and variable phase shifter have been designed and manufactured at CERN. They have been power tested, ﬁrst in a dedicated test and also in their ﬁnal conﬁguration, to en- sure stable power operation before installing them together with an accelerating structure. In this paper, we broadly describe the RF and mechanical design, manufacturing and low power measurements agreement with simulations. We report the high power qualiﬁcation of both components and their suitability to be used in existing and planned X-band facilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB064

About •

paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

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