IPAC2017 - List of Authors (Ziemann, V.G.)

Paper	Title	Page
MOPAB107	A Method for Determining the Roll Angle of the CLIC Accelerating Structures From the Beam Shape Downstream of the Structure	368
	J. Ögren, V.G. Ziemann Uppsala University, Uppsala, Sweden W. Farabolini CEA/DSM/IRFU, France
	The Compact Linear Collider (CLIC) accelerating structures have a four-fold symmetry from the radial waveguides for damping higher order modes. This symmetry allows for an octupole component of the rf fields to co-propagate with the main accelerating field. The effect of this octupole mode has been observed at the CLIC test facility 3. In CLIC the accelerating structures are mounted together on a moveable girders. There are four vertical and four horizontal actuators on the girder, which allows for 5D control in a limited range and for instance we can roll the girder. By observing the beam shape perturbed by the octupole field on a screen downstream from the structure we can determine the roll angle and thus align the structure azimuthally. Here we discuss a possible method and show some preliminary results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB107
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MOPAB108	Beam-Based Alignment Studies at CTF3 Using the Octupole Component of CLIC Accelerating Structures	371
	J. Ögren, A.K. Bhattacharyya, M. Holz, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden W. Farabolini CEA/DSM/IRFU, France
	The Compact Linear Collider (CLIC) uses normal-conducting accelerating structures that are sensitive to wakefield effects and therefore their alignment is extremely important. Due to the four-fold symmetry of the structures, they allow for an octupole component of the rf fields. By scanning the beam transversely we can determine the center of the structures from the shifts in beam position due to the kicks from the octupole field. We present some initial results from measurements at the CLIC test facility 3 at CERN.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB108
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TUPIK084	The EPICS Based Control System at the FREIA Laboratory	1890
	K. Fransson, K.J. Gajewski, M. Jacewicz, M. Jobs, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden
	FREIA (Facility for REsearch and Instrumentation for Accelerator development) Laboratory at Uppsala University, Sweden, is a new facility, inaugurated 2013. Initially FREIA is testing and developing superconducting accelerating cavities and high power RF sources in collaboration with the European Spallation Source (ESS). Later projects include testing of superconducting cavities and magnets for the high luminosity LHC. The high level control, alarm system and archiving is implemented in EPICS. Presently this includes a helium liquefaction plant, a horizontal test cryostat, two high power RF amplifiers, a low level RF system, environment monitoring and safety systems. Some attention will be given to integration of commercially acquired systems as well as the safety system, interlocks and radiation monitoring. The implementation of the EPICS environment follows closely that of ESS and thus can provide a test bench for developments at ESS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK084
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WEPIK086	Wave Propagation in a Fractal Wave Guide	3128
	V.G. Ziemann, A.K. Bhattacharyya, M. Holz, J. Ögren Uppsala University, Uppsala, Sweden
	We analyze the propagation of electro-magnetic waves in a wave guide that has the shape of Koch's snowflake, a well-known fractal.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK086
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THPVA021	Dynamics of Spectator Particles in Space-Charge Fields of Mismatched Beams With Cross-Plane Coupling	4462
	M. Holz, V.G. Ziemann Uppsala University, Uppsala, Sweden
	In accelerators with high beam power, even moderate beam losses must be avoided. These losses are due to particles reaching large transverse amplitudes that form a low density halo orbiting the beam core. To study the beam halo formation, we place a spectator particle outside the beam core and let it interact with the core's electric field. The core, we model by a self-consistent transverse Gaussian beam including non-linear space charge forces and cross-plane coupling.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA021
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Paper

Title

Page

A Method for Determining the Roll Angle of the CLIC Accelerating Structures From the Beam Shape Downstream of the Structure

368

J. Ögren, V.G. Ziemann
Uppsala University, Uppsala, Sweden
W. Farabolini
CEA/DSM/IRFU, France

The Compact Linear Collider (CLIC) accelerating structures have a four-fold symmetry from the radial waveguides for damping higher order modes. This symmetry allows for an octupole component of the rf fields to co-propagate with the main accelerating field. The effect of this octupole mode has been observed at the CLIC test facility 3. In CLIC the accelerating structures are mounted together on a moveable girders. There are four vertical and four horizontal actuators on the girder, which allows for 5D control in a limited range and for instance we can roll the girder. By observing the beam shape perturbed by the octupole field on a screen downstream from the structure we can determine the roll angle and thus align the structure azimuthally. Here we discuss a possible method and show some preliminary results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB107

Export •

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

MOPAB108

Beam-Based Alignment Studies at CTF3 Using the Octupole Component of CLIC Accelerating Structures

371

J. Ögren, A.K. Bhattacharyya, M. Holz, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden
W. Farabolini
CEA/DSM/IRFU, France

The Compact Linear Collider (CLIC) uses normal-conducting accelerating structures that are sensitive to wakefield effects and therefore their alignment is extremely important. Due to the four-fold symmetry of the structures, they allow for an octupole component of the rf fields. By scanning the beam transversely we can determine the center of the structures from the shifts in beam position due to the kicks from the octupole field. We present some initial results from measurements at the CLIC test facility 3 at CERN.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB108

Export •

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

TUPIK084

The EPICS Based Control System at the FREIA Laboratory

1890

K. Fransson, K.J. Gajewski, M. Jacewicz, M. Jobs, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden

FREIA (Facility for REsearch and Instrumentation for Accelerator development) Laboratory at Uppsala University, Sweden, is a new facility, inaugurated 2013. Initially FREIA is testing and developing superconducting accelerating cavities and high power RF sources in collaboration with the European Spallation Source (ESS). Later projects include testing of superconducting cavities and magnets for the high luminosity LHC. The high level control, alarm system and archiving is implemented in EPICS. Presently this includes a helium liquefaction plant, a horizontal test cryostat, two high power RF amplifiers, a low level RF system, environment monitoring and safety systems. Some attention will be given to integration of commercially acquired systems as well as the safety system, interlocks and radiation monitoring. The implementation of the EPICS environment follows closely that of ESS and thus can provide a test bench for developments at ESS.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK084

Export •

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

WEPIK086

Wave Propagation in a Fractal Wave Guide

3128

V.G. Ziemann, A.K. Bhattacharyya, M. Holz, J. Ögren
Uppsala University, Uppsala, Sweden

We analyze the propagation of electro-magnetic waves in a wave guide that has the shape of Koch's snowflake, a well-known fractal.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK086

Export •

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

THPVA021

Dynamics of Spectator Particles in Space-Charge Fields of Mismatched Beams With Cross-Plane Coupling

4462

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

In accelerators with high beam power, even moderate beam losses must be avoided. These losses are due to particles reaching large transverse amplitudes that form a low density halo orbiting the beam core. To study the beam halo formation, we place a spectator particle outside the beam core and let it interact with the core's electric field. The core, we model by a self-consistent transverse Gaussian beam including non-linear space charge forces and cross-plane coupling.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA021

Export •

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