IPAC2014 - List of Authors (Ziemann, V.G.)

Paper	Title	Page
MOPRO002	The Momentum Distribution of the Decelerated Drive Beam in CLIC and in the Two-beam Test Stand at CTF3	62
	Ch. Borgmann, M. Jacewicz, J. Ögren, M. Olvegård, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden
	We present analytical calculations of the momentum spectrum of the drive beam in CLIC and the CLIC Test Facility CTF3 after part of its kinetic energy is converted to microwaves for the acceleration of the main beam. The resulting expressions are used to determine parameters of the power conversion process in the Power Extraction Structure (PETS) installed in the Two-beam Test Stand in CTF3.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO002
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WEPME012	Solid-State Amplifier Development at FREIA	2282
	D.S. Dancila, A. Rydberg Uppsala University, Department of Engineering Sciences, Uppsala, Sweden A. Eriksson, V.A. Goryashko, L.F. Haapala, R.J.M.Y. Ruber, R. Wedberg, R.A. Yogi, V.G. Ziemann Uppsala University, Uppsala, Sweden
	The FREIA laboratory is a Facility for REsearch Instrumentation and Accelerator development at Uppsala University, Sweden, constructed recently to test and develop superconducting accelerating cavities and their high power RF sources. FREIA's activity target initially the European Spallation Source (ESS) requirements for testing spoke cavities and RF power stations, typically 400 kW per cavity. Different power stations will be installed at the FREIA laboratory. The first one is based on vacuum tubes and the second on a combination of solid state modules. In this context, we investigate different related aspects, such as power generation and power combination. For the characterization of solid-state amplifier modules in pulsed mode, at ESS specifications, we implemented a Hot S-parameters measurement set-up, allowing in addition the measurement of different parameters, such as gain and efficiency. We developed also a new solid-state amplifier module at 352 MHz, using commercially available LDMOS transistors. Preliminary results show a drain efficiency of 71% at 1300 W pulsed output power.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME012
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WEPRI110	The HNOSS Horizontal Cryostat and the Helium Liquefaction Plant at FREIA	2759
	R. Santiago Kern, T.J.C. Ekelöf, K.J. Gajewski, L. Hermansson, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden P. Bujard, N.R. Chevalier, T. Junquera, J.P. Thermeau Accelerators and Cryogenic Systems, Orsay, France
	A horizontal cryostat to test superconducting cavities and magnets at liquid helium temperatures is installed at FREIA (Facility for REsearch Instrumentation and Accelerator development) at Uppsala University, Sweden. The cryostat allows full testing of superconducting spoke and elliptical accelerating cavities without the need of a specialized cryomodule per cavity. Because horizontal cryostats are custom-built, their number in the accelerator world is very limited. The FREIA horizontal cryostat is one of a kind as it has been designed to be versatile: it is able to house either two ESS double-spoke, or two ESS/TESLA type elliptical cavities, or superconducting magnets or a combination of these with all the ancillary equipment (power couplers, tuners, etc) and test them at the same time, reducing installation time but requiring extra design effort and cryogens supply. In order to achieve this, a helium liquefier with a capacity of 140 l/h delivers liquid helium to the horizontal cryostat while the return gases are directed towards a recovery system, connected in closed loop with the liquefier.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI110
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THPRO024	Progress of the EU-XFEL Laser Heater	2912
	M. Hamberg, V.G. Ziemann Uppsala University, Uppsala, Sweden
	Funding: Swedish research council under Project number DNR-828-2008-1093 for financial support. We describe the technical layout and report the status of the installation of the undulator, optical and vacuum systems of the laser heater for the EUXFEL. The laser heater is a device to increase the overall X-ray brightness stability. This is achieved by an optical laser system which induce an additional momentum spread in the electron bunches to reduce micro-bunching instabilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO024
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THPRO025	Conceptual Design of a X-FEL Facility using CLIC X-band Accelerating Structure	2914
	A.A. Aksoy, Ö. Yavaş Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey D. Angal-Kalinin, J.A. Clarke Cockcroft Institute, Warrington, Cheshire, United Kingdom M.J. Boland SLSA, Clayton, Australia G. D'Auria, S. Di Mitri, C. Serpico Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy M. Doğan Dogus University, Istanbul, Turkey T.J.C. Ekelöf, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden W. Fang, Q. Gu SINAP, Shanghai, People's Republic of China A. Latina, D. Schulte, S. Stapnes, I. Syratchev, W. Wuensch CERN, Geneva, Switzerland Z. Nergiz Nigde University, Nigde University Science & Art Faculty, Nigde, Turkey
	Within last decade a linear accelerating structure with an average loaded gradient of 100 MV/m at 12 GHz has been demonstrated in the CLIC study. Recently, it has been proposed to use the CLIC structure to drive an FEL linac. In contrast to CLIC the linac would be powered by klystrons not by a drive beam. The main advantage of this proposal is achieving the required energies in a very short distance, thus the facility would be rather compact. In this study, we present the conceptual design parameters of a facility which could generate laser photon pulses covering the range of 1-75 Angstrom. Shorter wavelengths could also be reached with slightly increasing the energy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO025
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THPRO076	Frequency Maps Analysis of Tracking and Experimental Data for the SLS Storage Ring	3056
	P. Zisopoulos, F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland A. Streun PSI, Villigen PSI, Switzerland V.G. Ziemann Uppsala University, Uppsala, Sweden
	Frequency Maps Analysis (FMA) has been widely used in beam dynamics in order to study dynamical aspects of the particles linear and non-linear motion, such as optics functions distortion, coupling, tune-shift and resonances. In this paper, FMA is employed to explore the dynamics of models of the Swiss Light Source (SLS) storage ring and compare them with measured turn by turn (TxT) position data. In particular, a method is proposed for estimating the momentum spread using synchrotron sidebands of the Fourier spectrum of the TxT data.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO076
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THPRO077	The New FREIA Laboratory for Accelerator Development	3059
	R.J.M.Y. Ruber, A.K. Bhattacharyya, T.J.C. Ekelöf, K. Fransson, K.J. Gajewski, V.A. Goryashko, L. Hermansson, M. Jacewicz, T. Lofnes, M. Olvegård, R. Santiago Kern, R. Wedberg, R.A. Yogi, V.G. Ziemann Uppsala University, Uppsala, Sweden D.S. Dancila, A. Rydberg Uppsala University, Department of Engineering Sciences, Uppsala, Sweden
	The FREIA laboratory is a Facility for REsearch Instrumentation and Accelerator Development at Uppsala University, Sweden constructed recently to develop and test accelerator components. Initially it will develop the RF system for the spoke cavities of the ESS linac and test prototype spoke cavities at nominal RF power. For this purpose we installed a helium liquefaction plant, a versatile horizontal test cryostat and two 352 MHz RF power stations, one based on two tetrodes and the other on solid state technology. Beyond these developments FREIA will house a neutron generator and plans for a THz FEL are under discussion. FREIA is embedded in the Ångström physics, chemistry and engineering campus at Uppsala in close proximity to mechanical workshops, clean room with electron microscopes, tandem accelerator and the biomedical center.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO077
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THPRO078	Time-dependent Behaviour of Gas Ejected from an Accelerating Structure after a Discharge	3062
	V.G. Ziemann Uppsala University, Uppsala, Sweden
	Funding: This work is supported by the 7th European Framework program EuCARD under grant number 227579. A discharge or RF-breakdown event in a CLIC acceleration structure causes the localized release of gas molecules inside a thin conduction limited system with distributed pumping. We discuss the transient behavior of such a system in the molecular flow regime that allows an analytical solution with the help of Greens functions. They describe the temporal evolution of the gas density and the gas flow ejected from the ends of thin pipes of finite length. Distributed pumping, for example through the HOM damping slits is taken into account.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO078
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THPME171	General-purpose Spectrometer for Vacuum Breakdown Diagnostics for the 12 GHz Test Stand at CERN	3668
	M. Jacewicz, Ch. Borgmann, J. Ögren, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden
	Funding: This work is supported by the grants from the the Swedish Research Council DNR-2011-6305 and DNR-2009-6234. We discuss a spectrometer to analyze the electrons and ions ejected from a high-gradient CLIC accelerating structure that is installed in the klystron-driven 12 GHz test-stand at CERN. The charged particles escaping the structure provide useful information about the physics of the vacuum breakdown within a single RF pulse. The spectrometer consists of a dipole magnet, a pepper-pot collimator, a fluorescent screen and a fast camera. This enables us to detect both transverse parameters such as the emittance and longitudinal parameters such as the energy distribution of the ejected beams. We can correlate these measurements with e.g. the location of the breakdown inside the structure, by using information from the measured RF powers, giving in that way a complete picture of the vacuum breakdown phenomenon. The spectrometer was installed during Spring 2014 and will be commissioned during Summer 2014.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME171
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Paper

Title

Page

The Momentum Distribution of the Decelerated Drive Beam in CLIC and in the Two-beam Test Stand at CTF3

62

Ch. Borgmann, M. Jacewicz, J. Ögren, M. Olvegård, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden

We present analytical calculations of the momentum spectrum of the drive beam in CLIC and the CLIC Test Facility CTF3 after part of its kinetic energy is converted to microwaves for the acceleration of the main beam. The resulting expressions are used to determine parameters of the power conversion process in the Power Extraction Structure (PETS) installed in the Two-beam Test Stand in CTF3.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO002

Export •

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

WEPME012

Solid-State Amplifier Development at FREIA

2282

D.S. Dancila, A. Rydberg
Uppsala University, Department of Engineering Sciences, Uppsala, Sweden
A. Eriksson, V.A. Goryashko, L.F. Haapala, R.J.M.Y. Ruber, R. Wedberg, R.A. Yogi, V.G. Ziemann
Uppsala University, Uppsala, Sweden

The FREIA laboratory is a Facility for REsearch Instrumentation and Accelerator development at Uppsala University, Sweden, constructed recently to test and develop superconducting accelerating cavities and their high power RF sources. FREIA's activity target initially the European Spallation Source (ESS) requirements for testing spoke cavities and RF power stations, typically 400 kW per cavity. Different power stations will be installed at the FREIA laboratory. The first one is based on vacuum tubes and the second on a combination of solid state modules. In this context, we investigate different related aspects, such as power generation and power combination. For the characterization of solid-state amplifier modules in pulsed mode, at ESS specifications, we implemented a Hot S-parameters measurement set-up, allowing in addition the measurement of different parameters, such as gain and efficiency. We developed also a new solid-state amplifier module at 352 MHz, using commercially available LDMOS transistors. Preliminary results show a drain efficiency of 71% at 1300 W pulsed output power.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME012

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

WEPRI110

The HNOSS Horizontal Cryostat and the Helium Liquefaction Plant at FREIA

2759

R. Santiago Kern, T.J.C. Ekelöf, K.J. Gajewski, L. Hermansson, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden
P. Bujard, N.R. Chevalier, T. Junquera, J.P. Thermeau
Accelerators and Cryogenic Systems, Orsay, France

A horizontal cryostat to test superconducting cavities and magnets at liquid helium temperatures is installed at FREIA (Facility for REsearch Instrumentation and Accelerator development) at Uppsala University, Sweden. The cryostat allows full testing of superconducting spoke and elliptical accelerating cavities without the need of a specialized cryomodule per cavity. Because horizontal cryostats are custom-built, their number in the accelerator world is very limited. The FREIA horizontal cryostat is one of a kind as it has been designed to be versatile: it is able to house either two ESS double-spoke, or two ESS/TESLA type elliptical cavities, or superconducting magnets or a combination of these with all the ancillary equipment (power couplers, tuners, etc) and test them at the same time, reducing installation time but requiring extra design effort and cryogens supply. In order to achieve this, a helium liquefier with a capacity of 140 l/h delivers liquid helium to the horizontal cryostat while the return gases are directed towards a recovery system, connected in closed loop with the liquefier.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI110

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

THPRO024

Progress of the EU-XFEL Laser Heater

2912

M. Hamberg, V.G. Ziemann
Uppsala University, Uppsala, Sweden

Funding: Swedish research council under Project number DNR-828-2008-1093 for financial support.
We describe the technical layout and report the status of the installation of the undulator, optical and vacuum systems of the laser heater for the EUXFEL. The laser heater is a device to increase the overall X-ray brightness stability. This is achieved by an optical laser system which induce an additional momentum spread in the electron bunches to reduce micro-bunching instabilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO024

Export •

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

THPRO025

Conceptual Design of a X-FEL Facility using CLIC X-band Accelerating Structure

2914

A.A. Aksoy, Ö. Yavaş
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
D. Angal-Kalinin, J.A. Clarke
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M.J. Boland
SLSA, Clayton, Australia
G. D'Auria, S. Di Mitri, C. Serpico
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
M. Doğan
Dogus University, Istanbul, Turkey
T.J.C. Ekelöf, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden
W. Fang, Q. Gu
SINAP, Shanghai, People's Republic of China
A. Latina, D. Schulte, S. Stapnes, I. Syratchev, W. Wuensch
CERN, Geneva, Switzerland
Z. Nergiz
Nigde University, Nigde University Science & Art Faculty, Nigde, Turkey

Within last decade a linear accelerating structure with an average loaded gradient of 100 MV/m at 12 GHz has been demonstrated in the CLIC study. Recently, it has been proposed to use the CLIC structure to drive an FEL linac. In contrast to CLIC the linac would be powered by klystrons not by a drive beam. The main advantage of this proposal is achieving the required energies in a very short distance, thus the facility would be rather compact. In this study, we present the conceptual design parameters of a facility which could generate laser photon pulses covering the range of 1-75 Angstrom. Shorter wavelengths could also be reached with slightly increasing the energy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO025

Export •

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

THPRO076

Frequency Maps Analysis of Tracking and Experimental Data for the SLS Storage Ring

3056

P. Zisopoulos, F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland
A. Streun
PSI, Villigen PSI, Switzerland
V.G. Ziemann
Uppsala University, Uppsala, Sweden

Frequency Maps Analysis (FMA) has been widely used in beam dynamics in order to study dynamical aspects of the particles linear and non-linear motion, such as optics functions distortion, coupling, tune-shift and resonances. In this paper, FMA is employed to explore the dynamics of models of the Swiss Light Source (SLS) storage ring and compare them with measured turn by turn (TxT) position data. In particular, a method is proposed for estimating the momentum spread using synchrotron sidebands of the Fourier spectrum of the TxT data.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO076

Export •

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

THPRO077

The New FREIA Laboratory for Accelerator Development

3059

R.J.M.Y. Ruber, A.K. Bhattacharyya, T.J.C. Ekelöf, K. Fransson, K.J. Gajewski, V.A. Goryashko, L. Hermansson, M. Jacewicz, T. Lofnes, M. Olvegård, R. Santiago Kern, R. Wedberg, R.A. Yogi, V.G. Ziemann
Uppsala University, Uppsala, Sweden
D.S. Dancila, A. Rydberg
Uppsala University, Department of Engineering Sciences, Uppsala, Sweden

The FREIA laboratory is a Facility for REsearch Instrumentation and Accelerator Development at Uppsala University, Sweden constructed recently to develop and test accelerator components. Initially it will develop the RF system for the spoke cavities of the ESS linac and test prototype spoke cavities at nominal RF power. For this purpose we installed a helium liquefaction plant, a versatile horizontal test cryostat and two 352 MHz RF power stations, one based on two tetrodes and the other on solid state technology. Beyond these developments FREIA will house a neutron generator and plans for a THz FEL are under discussion. FREIA is embedded in the Ångström physics, chemistry and engineering campus at Uppsala in close proximity to mechanical workshops, clean room with electron microscopes, tandem accelerator and the biomedical center.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO077

Export •

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

THPRO078

Time-dependent Behaviour of Gas Ejected from an Accelerating Structure after a Discharge

3062

V.G. Ziemann
Uppsala University, Uppsala, Sweden

Funding: This work is supported by the 7th European Framework program EuCARD under grant number 227579.
A discharge or RF-breakdown event in a CLIC acceleration structure causes the localized release of gas molecules inside a thin conduction limited system with distributed pumping. We discuss the transient behavior of such a system in the molecular flow regime that allows an analytical solution with the help of Greens functions. They describe the temporal evolution of the gas density and the gas flow ejected from the ends of thin pipes of finite length. Distributed pumping, for example through the HOM damping slits is taken into account.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO078

Export •

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

THPME171

General-purpose Spectrometer for Vacuum Breakdown Diagnostics for the 12 GHz Test Stand at CERN

3668

M. Jacewicz, Ch. Borgmann, J. Ögren, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden

Funding: This work is supported by the grants from the the Swedish Research Council DNR-2011-6305 and DNR-2009-6234.
We discuss a spectrometer to analyze the electrons and ions ejected from a high-gradient CLIC accelerating structure that is installed in the klystron-driven 12 GHz test-stand at CERN. The charged particles escaping the structure provide useful information about the physics of the vacuum breakdown within a single RF pulse. The spectrometer consists of a dipole magnet, a pepper-pot collimator, a fluorescent screen and a fast camera. This enables us to detect both transverse parameters such as the emittance and longitudinal parameters such as the energy distribution of the ejected beams. We can correlate these measurements with e.g. the location of the breakdown inside the structure, by using information from the measured RF powers, giving in that way a complete picture of the vacuum breakdown phenomenon. The spectrometer was installed during Spring 2014 and will be commissioned during Summer 2014.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME171

Export •

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