TY  - CONF
AU  - Rönsch-Schulenburg, Juliane
AU  - Braune, Markus
AU  - Brenner-Abild, Günter
AU  - Dziarzhytski, Siarhei
AU  - Götze, Kathrin
AU  - Kuhlmann, Marion
AU  - Niknejadi, Pardis
AU  - Schaper, Lucas
AU  - Schneidmiller, Evgeny Alexanrdovich
AU  - Schoeps, Andreas
AU  - Tischer, Markus
AU  - Vagin, Pavel
AU  - Vogt, Mathias
AU  - Zemella, Johann
TI  - Operation of the variable polarization undulator on the third harmonic of a SASE FEL
JO  - Proceedings of SPIE
VL  - 13536
SN  - 0038-7355
CY  - Bellingham, Wash.
PB  - SPIE
M1  - PUBDB-2025-05846
SP  - 1353604
PY  - 2025
N1  - Waiting for fulltext 
AB  - FLASH is a XUV and soft X-ray free-electron laser and operates as a user facility since 2005. It comprises asuperconducting LINAC with a beam energy of up to 1.35 GeV which serves two FEL beamlines in parallel:FLASH1 and FLASH2. The FLASH2 main undulator beamline generates SASE radiation up to a photon energyof 390 eV in the fundamental. Additionally, an APPLE-III type undulator has been installed downstream ofthe FLASH2 SASE undulator section to generate soft X-ray radiation with tunable polarization at the thirdharmonic of the FLASH2 main undulator wavelength. Using this so-called afterburner, photons with up to860 eV have been demonstrated with selectable polarization. We describe the suppression of the strong thirdharmonic background radiation generated by the FLASH2 main undulator, which is linearly polarized and thusdisturbs the desired polarization state.
T2  - X-Ray Free-Electron Lasers: Advances in Source Development and Instrumentation VII
CY  - 7 Apr 2025 - 11 Apr 2025, Prague (Czech Republic)
Y2  - 7 Apr 2025 - 11 Apr 2025
M2  - Prague, Czech Republic
LB  - PUB:(DE-HGF)16 ; PUB:(DE-HGF)8 ; PUB:(DE-HGF)7
DO  - DOI:10.1117/12.3058405
UR  - https://bib-pubdb1.desy.de/record/643102
ER  -