IPAC2018 - List of Authors (Pforr, J.)

Paper	Title	Page
THPMF064	Beam Based Alignment of SRF Cavities in an Electron Injector Linac	4219
	F. Hug KPH, Mainz, Germany M. Arnold, T. Bahlo, J. Pforr, N. Pietralla TU Darmstadt, Darmstadt, Germany
	Funding: Funded by DFG through Cluster of Excellence EXC 1098/2014 "PRISMA" and RTG 2128 "AccelencE" and by the European Union's Horizon 2020 Research and Innovation programme under Grant Agreement No 730871 Proper alignment of accelerating cavities is an important issue concerning beam quality of accelerators. In particular SRF cavities of injector linacs using high accelerating gradients on low beta electron beams can affect the beam quality significantly when not aligned perfectly. On the other hand knowing the exact position of every cavity after several cool-down cycles of a cryomodule can be difficult depending on the cryomodule design. We will report on operational experience on the SC injector of the Darmstadt superconducting linac and ERL (S-DALINAC) showing unexpected effects on beam dynamics and beam quality. Operators could observe transverse beam deflections by changing accelerating phases of the injector SRF-cavities while a growth of tranverse emittance occurred at the same time. As beam currents in the S-DALINAC injector do never exceed 100 μA and the effects could even be observed at nA beam currents space-charge effects could be eliminated to be the reason for these observations. In this work we will report on the possibility to align SRF cavities after cooldown by measuring the transverse deflection of the beam and compare results with beam dynamics simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF064
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THPML087	First ERL Operation of S-DALINAC and Commissioning of a Path Length Adjustment System	4859
	M. Arnold, C. Burandt, R. Grewe, J. Pforr, N. Pietralla, M. Steinhorst TU Darmstadt, Darmstadt, Germany C. Eschelbach, M. Lösler Frankfurt University of Applied Sciences, Frankfurt am Main, Germany F. Hug KPH, Mainz, Germany
	Funding: Work supported by DFG through GRK 2128 and INST163/383-1/FUGG The S-DALINAC is running in recirculating operation since 1991. In 2015/2016 a major upgrade was performed by adding a third recirculation beam line. The versatility of this recirculation beam line enables a phase shift of the beam of up to 360° of the RF phase. The required range of 10 cm for a 3 GHz RF frequency is realized by a path length adjustment system. A complementary operation in normal scheme (single-pass, once or thrice recirculating with acceleration) or ERL mode (once or twice) is possible by appropriate adjustment of this system. After installation this system was aligned properly and its functionality and stroke was checked without beam. The system was commissioned by measuring the change of the beam phase in dependency of the setting of the path length adjustment system. The complementary usage of the newly installed recirculation for once recirculating with acceleration and once recirculating with ERL mode has been shown successfully in autumn 2017. This contribution will provide an overview on the path length adjustment system and the first run of the once recirculating ERL mode of the S-DALINAC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML087
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Beam Based Alignment of SRF Cavities in an Electron Injector Linac

4219

F. Hug
KPH, Mainz, Germany
M. Arnold, T. Bahlo, J. Pforr, N. Pietralla
TU Darmstadt, Darmstadt, Germany

Funding: Funded by DFG through Cluster of Excellence EXC 1098/2014 "PRISMA" and RTG 2128 "AccelencE" and by the European Union's Horizon 2020 Research and Innovation programme under Grant Agreement No 730871
Proper alignment of accelerating cavities is an important issue concerning beam quality of accelerators. In particular SRF cavities of injector linacs using high accelerating gradients on low beta electron beams can affect the beam quality significantly when not aligned perfectly. On the other hand knowing the exact position of every cavity after several cool-down cycles of a cryomodule can be difficult depending on the cryomodule design. We will report on operational experience on the SC injector of the Darmstadt superconducting linac and ERL (S-DALINAC) showing unexpected effects on beam dynamics and beam quality. Operators could observe transverse beam deflections by changing accelerating phases of the injector SRF-cavities while a growth of tranverse emittance occurred at the same time. As beam currents in the S-DALINAC injector do never exceed 100 μA and the effects could even be observed at nA beam currents space-charge effects could be eliminated to be the reason for these observations. In this work we will report on the possibility to align SRF cavities after cooldown by measuring the transverse deflection of the beam and compare results with beam dynamics simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF064

Export •

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

THPML087

First ERL Operation of S-DALINAC and Commissioning of a Path Length Adjustment System

4859

M. Arnold, C. Burandt, R. Grewe, J. Pforr, N. Pietralla, M. Steinhorst
TU Darmstadt, Darmstadt, Germany
C. Eschelbach, M. Lösler
Frankfurt University of Applied Sciences, Frankfurt am Main, Germany
F. Hug
KPH, Mainz, Germany

Funding: Work supported by DFG through GRK 2128 and INST163/383-1/FUGG
The S-DALINAC is running in recirculating operation since 1991. In 2015/2016 a major upgrade was performed by adding a third recirculation beam line. The versatility of this recirculation beam line enables a phase shift of the beam of up to 360° of the RF phase. The required range of 10 cm for a 3 GHz RF frequency is realized by a path length adjustment system. A complementary operation in normal scheme (single-pass, once or thrice recirculating with acceleration) or ERL mode (once or twice) is possible by appropriate adjustment of this system. After installation this system was aligned properly and its functionality and stroke was checked without beam. The system was commissioned by measuring the change of the beam phase in dependency of the setting of the path length adjustment system. The complementary usage of the newly installed recirculation for once recirculating with acceleration and once recirculating with ERL mode has been shown successfully in autumn 2017. This contribution will provide an overview on the path length adjustment system and the first run of the once recirculating ERL mode of the S-DALINAC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML087

Export •

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