{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"c287eba92bc84f483e52eb4b88c318c115131afa40c9f8e12a56dba6f86d3de3","created":"2026-10-03T07:17:56Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"c30e36b29489a36ee042ebe0059f7fcf53f01bfaec3fb7fa105189933e18049b","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":"1","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 1e-5 cm, which would reduce SASE start-up noise and microbunching gain.","problem_ref":null,"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":"62fcdc9c8f916869de7ec88dba711f39f0c92f912f69f270978376119dc0bcaa"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"a06d57a97500fbb06bcd199f631f9064f9f7d863240b4d02135b5524eb129551","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"60607c8b4c849322a0b1bc7886222f74287be5851ead711ebe1a1e66a097818d","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"_31D74WS1bClbE6P8wlnL6dAy5UZDRWmrsmTrnH35W020pVioKBPtgy1m-ldwGOw-yDsyGuV_g7aDB2jLyclAg"},"schema":"pubphys.envelope/1"},"record_hash":"a06d57a97500fbb06bcd199f631f9064f9f7d863240b4d02135b5524eb129551","leaf_index":667}