{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2013:UW37WBPWGDB4BW4FNNPZECV37S","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"b27dd2dad92e781862a521590c11382e126e01cdfa68414c4df698fff5282fcf","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.acc-ph","submitted_at":"2013-08-01T12:37:24Z","title_canon_sha256":"b5b2b1871f76796ad5c48a4346f28c5209bbb0023abb5cca81676494aa0c4ccc"},"schema_version":"1.0","source":{"id":"1308.0172","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1308.0172","created_at":"2026-05-18T03:16:59Z"},{"alias_kind":"arxiv_version","alias_value":"1308.0172v1","created_at":"2026-05-18T03:16:59Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1308.0172","created_at":"2026-05-18T03:16:59Z"},{"alias_kind":"pith_short_12","alias_value":"UW37WBPWGDB4","created_at":"2026-05-18T12:28:02Z"},{"alias_kind":"pith_short_16","alias_value":"UW37WBPWGDB4BW4F","created_at":"2026-05-18T12:28:02Z"},{"alias_kind":"pith_short_8","alias_value":"UW37WBPW","created_at":"2026-05-18T12:28:02Z"}],"graph_snapshots":[{"event_id":"sha256:e7326eddabe9172f0630e4167615bab6fbb62908cd32124f27525fcb1a952f7e","target":"graph","created_at":"2026-05-18T03:16:59Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"The purified SASE (pSASE) undulator configuration recently proposed at SLAC promises an increase in the output spectral density of XFELs. In this article we study a straightforward implementation of this configuration for the soft x-ray beamline at the European XFEL. A few undulator cells, resonant at a subharmonic of the FEL radiation, are used in the middle of the exponential regime to amplify the radiation, while simultaneously reducing the FEL bandwidth. Based on start-to-end simulations, we show that with the proposed configuration the spectral density in the photon energy range between 1","authors_text":"Evgeni Saldin, Gianluca Geloni, Igor Zagorodnov, Svitozar Serkez, Vitali Kocharyan","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.acc-ph","submitted_at":"2013-08-01T12:37:24Z","title":"Purified SASE undulator configuration to enhance the performance of the soft x-ray beamline at the European XFEL"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1308.0172","kind":"arxiv","version":1},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:b89feb7fc7ed3a8d788b65f4634faa522055f590ea3eb312567d613212e3d764","target":"record","created_at":"2026-05-18T03:16:59Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"b27dd2dad92e781862a521590c11382e126e01cdfa68414c4df698fff5282fcf","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.acc-ph","submitted_at":"2013-08-01T12:37:24Z","title_canon_sha256":"b5b2b1871f76796ad5c48a4346f28c5209bbb0023abb5cca81676494aa0c4ccc"},"schema_version":"1.0","source":{"id":"1308.0172","kind":"arxiv","version":1}},"canonical_sha256":"a5b7fb05f630c3c0db856b5f920abbfc8207bcb46fea851768f45e93d9150d08","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"a5b7fb05f630c3c0db856b5f920abbfc8207bcb46fea851768f45e93d9150d08","first_computed_at":"2026-05-18T03:16:59.622867Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T03:16:59.622867Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"nWRec0GISmrWJBcL3sEznr+g5cN2/tm6COjoxoLUvU1qASB8+tmJMPapPCfxb3XbsgQ/0nxiVD8zX57VRfBVCQ==","signature_status":"signed_v1","signed_at":"2026-05-18T03:16:59.623544Z","signed_message":"canonical_sha256_bytes"},"source_id":"1308.0172","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:b89feb7fc7ed3a8d788b65f4634faa522055f590ea3eb312567d613212e3d764","sha256:e7326eddabe9172f0630e4167615bab6fbb62908cd32124f27525fcb1a952f7e"],"state_sha256":"2553472b28a389be2b161f617f09ebb4c8eb6ce4083dff4f0d9805d218f8750b"}