{"paper":{"title":"Circular polarization control for the European XFEL in the soft X-ray regime","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"physics.acc-ph","authors_text":"Evgeni Saldin, Gianluca Geloni, Vitali Kocharyan","submitted_at":"2011-06-09T11:30:39Z","abstract_excerpt":"The possibility of producing highly circularly polarized X-ray radiation, especially in the soft X-ray region, is an important asset at XFELs. However, the baseline of the European XFEL, including the soft X-ray SASE3 line, foresees planar undulators only. The lowest-risk strategy for implementing polarization control at SASE3 involves adding an APPLE II-type undulator at the end of the planar undulator, to exploit the microbunching from the baseline FEL. 5m-long APPLE II undulators are standard devices at synchrotrons. However, the choice of a short helical radiator leads to the problem of ba"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1106.1776","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}