Powering test results of HTS undulator prototype coils for compact FELs at 4.2 K
Richter, S.
1; Grau, A. 1; Jauregui, D. Saez de 1; Ballarino, A.; Glamann, N. 1; Nes, T.; Schoerling, D.; Bernhard, A.
1; Müller, A.-S.
1
1 Institut für Beschleunigerphysik und Technologie (IBPT), Karlsruher Institut für Technologie (KIT)
1; Grau, A. 1; Jauregui, D. Saez de 1; Ballarino, A.; Glamann, N. 1; Nes, T.; Schoerling, D.; Bernhard, A.
1; Müller, A.-S.
11 Institut für Beschleunigerphysik und Technologie (IBPT), Karlsruher Institut für Technologie (KIT)
Abstract:
Short-period and high-field undulators are crucial for the production of coherent light
up to X-rays in compact free-electron lasers (FELs). Besides, future colliders like CLIC or FCC-ee
demand high-field damping wigglers to reach a low beam emittance. Both applications may
benefit from the use of high-temperature superconductors (HTS), e.g., by providing high magnetic
field amplitudes or higher operating temperatures. This paper presents and summarizes our HTS
undulator prototype coils, designed and manufactured at CERN, made from coated REBCO tape
superconductor. The coil design, described and already powered at 77 K in previous works, is
based on no-insulation (NI) vertical racetracks with a period length of 13 mm, assembled with iron
poles. Powering tests of several HTS undulator prototype coils at 4.2 K, performed at KIT, revealed
safe operations at high engineering current densities of 2.3 kA/mm$^2$ with produced magnetic fields
of up to 1.5 T at 3.5 mm distance from the magnetic iron poles. Reasonable effective time
constants of around 100 s were obtained and further powering tests in regions beyond Je,c with
3.6 kA/mm$^2$ showed the stability of our NI design and created magnetic fields in the region of 2 T.
up to X-rays in compact free-electron lasers (FELs). Besides, future colliders like CLIC or FCC-ee
demand high-field damping wigglers to reach a low beam emittance. Both applications may
benefit from the use of high-temperature superconductors (HTS), e.g., by providing high magnetic
field amplitudes or higher operating temperatures. This paper presents and summarizes our HTS
undulator prototype coils, designed and manufactured at CERN, made from coated REBCO tape
superconductor. The coil design, described and already powered at 77 K in previous works, is
based on no-insulation (NI) vertical racetracks with a period length of 13 mm, assembled with iron
poles. Powering tests of several HTS undulator prototype coils at 4.2 K, performed at KIT, revealed
safe operations at high engineering current densities of 2.3 kA/mm$^2$ with produced magnetic fields
of up to 1.5 T at 3.5 mm distance from the magnetic iron poles. Reasonable effective time
constants of around 100 s were obtained and further powering tests in regions beyond Je,c with
3.6 kA/mm$^2$ showed the stability of our NI design and created magnetic fields in the region of 2 T.
| Zugehörige Institution(en) am KIT | Institut für Beschleunigerphysik und Technologie (IBPT) Laboratorium für Applikationen der Synchrotronstrahlung (LAS) |
| Publikationstyp | Forschungsbericht/Preprint |
| Publikationsmonat/-jahr | 10.2022 |
| Sprache | Englisch |
| Identifikator | KITopen-ID: 1000153871 |
| HGF-Programm | 54.11.11 (POF IV, LK 01) Accelerator Operation, Research and Development |
| Bemerkung zur Veröffentlichung | in press |
| Externe Relationen | Konferenz |
| Schlagwörter | Free electron lasers, high-temperature superconductors, superconducting devices, undulators |