{"schema":"pubphys.bundle/1","record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"6ea9fb42729c3e6e15fbe287f74cd1c41c6b19f8d201ab333f36ac58629e916a","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["91628ed177e96e50cb4b1e908fdd7876ed07b1198939d8e060097f0b18dd5c67","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"7293c8d215b1f4afd00dbf9711186f1a4bcc15b61ecba89e0eb05248c96b07db","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"beams.srf-cavities.high-field-q-slope","kind":"phenomenon","literature_status":"contested","n":"2","parents":[],"plain":"Above a certain field, niobium cavities start wasting far more energy; a two-day bake at 120 C removes the effect, and why it works is still debated.","posed_since":"","precise":"Electropolished bulk Nb cavities at $1.3\\,\\mathrm{GHz}$ and $T = 2\\,\\mathrm{K}$ show a steep drop of quality factor $Q_0$ above peak surface magnetic field $H_{\\mathrm{pk}} \\sim 900-1000\\,\\mathrm{G}$, removed by in-situ baking at $120\\,\\mathrm{C}$ for $\\sim 48\\,\\mathrm{h}$. Identify the mechanism (niobium nanohydride precipitation within $\\sim 10^{-5}$ cm of the surface, oxygen or vacancy-hydrogen complexes, or other) with a model predicting the onset field and its dependence on bake temperature and duration.","problem_ref":"91628ed177e96e50cb4b1e908fdd7876ed07b1198939d8e060097f0b18dd5c67","references":"","settled_by":"Depth-resolved measurement of hydrogen, oxygen and vacancy profiles before and after baking, correlated with $Q_0(H_{\\mathrm{pk}})$ of the same cavities and matched by a quantitative model.","status_note":"Hydride-precipitation and impurity (oxygen, vacancy-hydrogen) explanations each have supporting studies; no consensus was found in records checked through 2025.","title":"Mechanism of the high-field Q-slope and its cure by baking","topic_ref":null},"content_withheld":"false","files":[],"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"33873c854833a0ae6f539bbbb12dbda67842c4bc33912a28fc66a15962b98952","schema":"pubphys.attested/1"},"id_token":null,"id_token_withheld":"false","envelope":{"attested_hash":"4b5efac84c0b6bf20037fa7ed8f0508c9b6f7a8be74064b4200c719397f369ff","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"Rwf2AlJxCy9_ckRdCWepUMK1ToGRvQcbmWOCT_q8Q7yb_0AXTjnV7CgwfNPesGVQCp4Xrgdvm7Qv0p4XTc6-Aw"},"schema":"pubphys.envelope/1"},"ots":{"attested":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEIS176yEwLa_IAN_p-2PBQjJtveovnQGS0IAxxk5fzaf_wIEuN3GMa9K5fSnZ06She7aU-IvdNsFhQ_aGAurIlyQtiCPAg0q6a2LwweX-mjFxQhw4LM02kspe7K_lsVvYA2l9-CCUI8CBK95IMA6XATHGx88_SkIUhgMCvzFx-NzUv6Bt60baSmwjwIL7SeZMzPQbU1gEnnzYYE2wiox1JYgZ7CkAmwLRe0B4ICPAgBB59Y-zGAfQ_1H-Zy9LSTCynI71mUGiu6XnQoDefy3EI8SBMtrWk8G8drtYgPSQAVqEJtzVHOx3Zy4Kn4m6mKJXP6AjxIBhB27X2sRsQbro8Joy-wdFNSVpVeMYyKR4AYna50JaDCPEgY6scDRpMTELRyAdQzoM_M72JG6gtvT5rKuV0H9Htq4AI8SDYW1nvfhAbf15fxYweLGiGtYK21xyRv_zJHX5DdVcU4wjxIJdQdDsL3v2lA7qZb8kMJtOgaTQmbgchdPcS5lYJqDLnCPAgkPXX-naXR0fRIdS-sEDlzYmtMvSCNH42ESUF0QXb6NUI8CDQo_sIWZiWXaTGRSQBLmU-lHJKskYKqsjO1r02DhB8LAj_8Ajn9YmozHwo9QjwEJ46aM9ZDv3TdtqV3ZbRsNgI8SBOF8pILGf1kodr5MKmQs6Cd93joraGn3g6UPt_-kewPwjwIOG-gmM7bd_eR4AiDMNfluS3xvr7vicLR-sCBr5qtG2cCPAgrVNFrCoeQcCxhlmnE0BzHgR8HQpZAlfqzDDFzfWb8GUI8QRq0WWT8AjZJ2cF_c7k8ACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AI9ZMS1zxd7IEI8BDd00WgJZ0RncsC1Fyai_4aCPEgvxMFrnu7F05IW5INiraQ3OVEYMjNx6JfBxw1Q4jPLi4I8QRq0WWS8Ag2zxPAtI5JsP8Ag9_jDS75DI4uLWh0dHBzOi8vYWxpY2UuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZwjxIHAnv4KFFf4uiYEFJvLxiMxSyz8VowJP4roTfDD9h7bICPAgj5tgvbNF7mxSP4jGGE66ezUFRLnI4g1VTkvuV4VtCPAI8CCxlc1HuKORuHgn7DYIYcDhc4oo99OkTWBEvddBypoa7AjwIFcjjaF8kDNDYCZGaNISlRjvX-I7in-QNwsr4JYQbFJvCPAgnl0k4gs7LuY5i1umiHO-J7My3uBThLJUWQoY9LdVSrQI8SA6-Ft11_K_GqMNWYhkVsVqCFvXSYbp4S8JoLsLBnUzvgjxIBC8_mAE7JBP35SNxDBcG7joLJwURpMxdV2vSO64_jEOCPEge04Coj1xSi7CE8UwqiBGNhPyZ5QdD_YZwn-heSdObU4I8SBgdDSgr3VUx1j8m_pK7-OzMwwFgXeLy43ujffCv-hf5AjwIMl-PnAt4xjoBEVU4-nkyN0NKRa9AvX4kEMfllFyIJS9CPFZAQAAAAHz4rV-uwQFg02bVnEMUFgpIdGKjM4tWuID1kTVnrjisAAAAAAA_v___wJURAIAAAAAABYAFBFys2oc0-U-bYrC3VulGLzND5fbAAAAAAAAAAAiaiDwBHLTDgAICPEgMJIBYi46xOIuFDwzJ9nOx14ngW5HbglUf65ORpkoIYcICPAgHgGWEGCDHWgscwT92NOoJ7s-ezbPkyiWr2RnYZDC_dwICPAgtffMyyLu-MscJsDc0dzwGspwSrrmvVAnMNgsgWhHClgICPAgMUl1OfBDUwhp5VZjHwVA0nuz1F5HZTUJCHAnM1L1F3MICPAgStK7UWpnrUueV5EaE7uE0y6BLMp6EANmrbhrTqEBZu8ICPAg5LVW7IHtUL5mNOvPx1hOTfLMmqlQ7t9EFW-KDtrISIQICPAgABgXZ6upFU8qiDQKFtQFpqkjKwl0PsxM4JUjVLlDKbkICPAgEwb96FiOhjlbwI8GFZQ4a5GXwxs4bUdqVOMKrtBWV30ICPEgqBg-wp0c8CAPV9k6J7wIa9_GtQfpWmhpE1zqFZyi2pQICPAg2pZLTVPGJbriiz0UhMytYDVYAXOgQnWDcrMOewK9O8cICPEgxm3QwzbvT4siJzubQGnST67bWv-exYwSPP1KDi7CaUwICPEgm6udUudfjUaM0gUFTylKGDMypj7ptMTG0zmxd_T5yTcICPAgMpOInkjFCVp1pOZhfZnyPAl8hdWGmHzQcrGLgLwSKLgICAAFiJYNc9cZAQPzpjs"],"envelope":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEIGAb2YHiR4e5Yvks9l40fV3YqXxWrVzEs_KKuvvP8_3bwIBgI_Td1EXsNVM6YBxy5LNCZV4e8BsqHcTk9kjvnUrPvCPAgSJHY_oje8ayvNa-_WJOTxzlydscy0tS3fnWEElwkbLoI8CC3-GiBy5P3f-24BPgtJ2a89OusDOp6nCQeB3XyQfVq5wjxIJvuHrcwutYtbv5t64zpn8PPVSAkzlpOK7ArM5mQwHvrCPAgYexafEjpQ9vzSEaAtXVhBPcLBl6gwIF8GaQ1LcenusMI8CCZuLxzSo7DS6ZOWMSzN49DR2ErUApDSJWkyZ4IAcoEPQjxILNBbiMXjFx2nLAsqq2yLOEYPPpEYUfXyZmHy3ijHVMeCPAgQEjWwWlWWX3vJoLxfq0lixNb2cwGMRGhB0ekxjFJDZAI8SCHI26f1bMr-H5VtXG_HgMHDd8PPImPLhsWPB8PPaY3jwjwIKD8mGRUgbk2Dt1xG-4OxMpCuw1ya5UEUQXsqASURGCtCPAgkPXX-naXR0fRIdS-sEDlzYmtMvSCNH42ESUF0QXb6NUI8CDQo_sIWZiWXaTGRSQBLmU-lHJKskYKqsjO1r02DhB8LAj_8Ajn9YmozHwo9QjwEJ46aM9ZDv3TdtqV3ZbRsNgI8SBOF8pILGf1kodr5MKmQs6Cd93joraGn3g6UPt_-kewPwjwIOG-gmM7bd_eR4AiDMNfluS3xvr7vicLR-sCBr5qtG2cCPAgrVNFrCoeQcCxhlmnE0BzHgR8HQpZAlfqzDDFzfWb8GUI8QRq0WWT8AjZJ2cF_c7k8ACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AI9ZMS1zxd7IEI8BDd00WgJZ0RncsC1Fyai_4aCPEgvxMFrnu7F05IW5INiraQ3OVEYMjNx6JfBxw1Q4jPLi4I8QRq0WWS8Ag2zxPAtI5JsP8Ag9_jDS75DI4uLWh0dHBzOi8vYWxpY2UuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZwjxIHAnv4KFFf4uiYEFJvLxiMxSyz8VowJP4roTfDD9h7bICPAgj5tgvbNF7mxSP4jGGE66ezUFRLnI4g1VTkvuV4VtCPAI8CCxlc1HuKORuHgn7DYIYcDhc4oo99OkTWBEvddBypoa7AjwIFcjjaF8kDNDYCZGaNISlRjvX-I7in-QNwsr4JYQbFJvCPAgnl0k4gs7LuY5i1umiHO-J7My3uBThLJUWQoY9LdVSrQI8SA6-Ft11_K_GqMNWYhkVsVqCFvXSYbp4S8JoLsLBnUzvgjxIBC8_mAE7JBP35SNxDBcG7joLJwURpMxdV2vSO64_jEOCPEge04Coj1xSi7CE8UwqiBGNhPyZ5QdD_YZwn-heSdObU4I8SBgdDSgr3VUx1j8m_pK7-OzMwwFgXeLy43ujffCv-hf5AjwIMl-PnAt4xjoBEVU4-nkyN0NKRa9AvX4kEMfllFyIJS9CPFZAQAAAAHz4rV-uwQFg02bVnEMUFgpIdGKjM4tWuID1kTVnrjisAAAAAAA_v___wJURAIAAAAAABYAFBFys2oc0-U-bYrC3VulGLzND5fbAAAAAAAAAAAiaiDwBHLTDgAICPEgMJIBYi46xOIuFDwzJ9nOx14ngW5HbglUf65ORpkoIYcICPAgHgGWEGCDHWgscwT92NOoJ7s-ezbPkyiWr2RnYZDC_dwICPAgtffMyyLu-MscJsDc0dzwGspwSrrmvVAnMNgsgWhHClgICPAgMUl1OfBDUwhp5VZjHwVA0nuz1F5HZTUJCHAnM1L1F3MICPAgStK7UWpnrUueV5EaE7uE0y6BLMp6EANmrbhrTqEBZu8ICPAg5LVW7IHtUL5mNOvPx1hOTfLMmqlQ7t9EFW-KDtrISIQICPAgABgXZ6upFU8qiDQKFtQFpqkjKwl0PsxM4JUjVLlDKbkICPAgEwb96FiOhjlbwI8GFZQ4a5GXwxs4bUdqVOMKrtBWV30ICPEgqBg-wp0c8CAPV9k6J7wIa9_GtQfpWmhpE1zqFZyi2pQICPAg2pZLTVPGJbriiz0UhMytYDVYAXOgQnWDcrMOewK9O8cICPEgxm3QwzbvT4siJzubQGnST67bWv-exYwSPP1KDi7CaUwICPEgm6udUudfjUaM0gUFTylKGDMypj7ptMTG0zmxd_T5yTcICPAgMpOInkjFCVp1pOZhfZnyPAl8hdWGmHzQcrGLgLwSKLgICAAFiJYNc9cZAQPzpjs"]},"log":{"leaf_index":"2536","tree_size":"3804","proof":["e2b8dc900e4f7a2fbedb90fd8a283884dd796ba3b5917425109b001af5918ce1","91f28113e0ffa1875b5e62341b1f86623df146a7193c5262a8cd6426da9be8ce","3e06f01e3304179df159404bdcfe2d7a1b084dc04c5016560a071b8ced337065","ce88f230e2bb3e95e69e8d721cacabb29ac8ce7a0c5f3e0eea1baf76a59626d3","01e1bca33c7c73a66e2fb9c8cb5cb12ee87dcaaa093abb0810ba6b432fd67d8e","68d0b7b41f691a13cffad5a3630ddf8db98cced19189ca7fbd51c8693b99037e","7c0747095d37385fe6f4d152c1a4f15f2c176d36931329cf6ad82b081e9f63f6","193f7e120934503cd45d11622182f80d8b1635765c3becdc1c2cab15bb00bcc2","ad2bf8922b230304eb5887f66a1631d0d013048aef3d1e5c2bce55da65e76cef","453fe2db8b5276d732edac85634e8be036b4709a91a2584f32a4b9edcc8ca9de","325287f5a43e4f3ad4072ec4bd53d43c50c1393021a056122e9cb0fad83b868f","3c578dccc15502c5f3efe228cadc99fee76ab536ed01f66b14d316fdcc157429"],"checkpoint":"pubphys.com/log/v1\n3804\nAK6t4qgu96+M9wScTrIlsJ10d/zhKVEtYguyM3aeJvo=\n\n— pubphys.com/log/v1 JFPwIPP8EtoxgcsQg7V7CwIdL4UKPqJtpv+eB8sFNJjyQHIdyA1VabmBsPyLqq2bLxJPn57rA6fQi8y0QDDjRXHvlQg=\n","promise":"pubphys.com/log/v1 promise\nb557b9392b0e6fb7bcffa6c9b5dd60f9d4a93cc2eece8c0e3d4a42f2cd16ea85\n2536\n2026-10-15T23:43:57Z\n2026-10-16T01:43:57Z\n\n— pubphys.com/log/v1 JFPwINL4Y4jPYmFd1zNu2SE0xZ+MEPM/8tHtTRhKyk4iQvAe7VTr6B7aYa7obVXCjju3RDXZbqDRv8fvztKXQ5jk8AE=\n"},"orcid_key_evidence":[],"attesting":null}