{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"e79cbfe33f6ef424fb5b4690a9163edf917582f8d18162d4c108d5729d3564ab","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["a06d57a97500fbb06bcd199f631f9064f9f7d863240b4d02135b5524eb129551","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"fe07e0d442bbea27a599e52cfff318f02e7773bdbd8cf933d348444d617ab943","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"beams.fel-physics.shot-noise-suppression","kind":"well-posed","literature_status":"partially-resolved","n":"2","parents":[],"plain":"Electrons arrive at random, which seeds noisy x-ray output and harmful instabilities; collective forces can make them more evenly spaced than random, but only at long wavelengths so far.","posed_since":"","precise":"Coulomb repulsion acting over a quarter plasma period in a drift can reduce beam density fluctuations below the Poisson shot-noise level. Determine whether suppression by more than 10 dB can be produced and kept through acceleration and compression at wavelengths below $10^{-5}$ cm, which would reduce SASE start-up noise and microbunching gain.","problem_ref":"a06d57a97500fbb06bcd199f631f9064f9f7d863240b4d02135b5524eb129551","references":"","settled_by":"Measured coherent radiation from a beam below the shot-noise level at the stated wavelength after acceleration and compression.","status_note":"Sub-shot-noise density fluctuations were reported at optical wavelengths in the 2010s; suppression at XUV and x-ray wavelengths is undemonstrated.","title":"Suppressing electron-beam shot noise below the random level","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"1ad4e55e46738b725318ca72b2b7536abd5c18ef3923522e1f9e3acda4c025f9","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"53100880332450f1d7cec23ae0fb638a6647d7cd4937e725d063e88e4d655c8c","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"FCSuw1v2xYLMEQAWDMyjsaExCUAuSGaftDJBDfWUBSjdHaPX2AkwhOuw_i4cL3UnC5-R5Oi66u_KQos3NnQCDA"},"schema":"pubphys.envelope/1"},"record_hash":"1ad4e55e46738b725318ca72b2b7536abd5c18ef3923522e1f9e3acda4c025f9","leaf_index":2480}