{"schema":"pubphys.bundle/1","record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"d6e17547adf0c9528989e9fcd4d13ae8384767c715e62b85afbd6921f6d81f0e","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["2c5794513268a91b15d1ae24d7fd99ca1992f261eecd5d4f3b7c3cee57a4b788","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"06bc13416e388bc8ce226e598d3e6412dd3e1a46be3726403ab3babac4d9009c","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"beams.nb3sn-cavities.exceed-nb","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"The goal of $\\mathrm{Nb_3Sn}$ is to go beyond niobium, but so far niobium still holds the gradient record. The question is whether any $\\mathrm{Nb_3Sn}$ cavity can beat it.","posed_since":"","precise":"Determine whether a $\\mathrm{Nb_3Sn}$-coated 1.3 GHz elliptical cavity can sustain $E_{\\mathrm{acc}}>0.45\\,\\mathrm{MV}/\\mathrm{cm}$ ($B_{\\mathrm{pk}}>1900\\,\\mathrm{G}$) at any temperature with $Q_{0}>10^{10}$, or whether intrinsic film properties (grain boundaries, thin-film thermal limits) forbid it.","problem_ref":"2c5794513268a91b15d1ae24d7fd99ca1992f261eecd5d4f3b7c3cee57a4b788","references":"","settled_by":"A $\\mathrm{Nb_3Sn}$ cavity test exceeding the Nb record gradient, or a demonstrated intrinsic bound below it.","status_note":"","title":"Can a $\\mathrm{Nb_3Sn}$ cavity exceed the gradient of the best niobium cavities?","topic_ref":null},"content_withheld":"false","files":[],"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"7a96dbed5b9be35e46c64d0f2558fd4334e663c3066fc3394c96685d1285bc6f","schema":"pubphys.attested/1"},"id_token":null,"id_token_withheld":"false","envelope":{"attested_hash":"2e9d8d38cf2e0b78b6a0f7d6d73b16151c483d3277b2984c40a80dd9b69bf9ba","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"rTn4jX4cJkzbQJtXEutCNxcnwdmNJlaSloFnIUiNNyl8WuqkeBkXZZwbXMqELDWajChV2kcSxHUgUeEWgcrJAw"},"schema":"pubphys.envelope/1"},"ots":{"attested":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEILp2NOM8uC3i2oPfW1zsWFRxIPTJ3sphMQKgN2bab-brwIC7DhmkmHRbx2mW1utUyYSMIRkZxGrGe20vboHAebb8PCPAgNrIqidrA4fPkxhtfnEEHIpDYD_Dz_0Z0b3pTUGuLz9II8CAZ7nko7yL5k1q4nNX4tddjeeczfsG7cmVscEFIP-qAcgjxIBoNJEMX98J70d66iMzHdXz_m8fdvfP7mRfVMdbcTJQ5CPEgJG2v49I-8PJK8aQfoWG80wt9agzJFcR9DLBNiooyadUI8SBloKxI-lzdqq1qZUUfrAsuky147x0gLMnTmShJgUjX8gjxIMhoWfPGstYw3Keh70T7fvP4lgFTgttM_Gzfl83V7x1QCPAg_wIiPkLJd3-DTpBID5KVkTGoJ2F0twCyomKLdpQPO3UI8CDsCcIzBovmyR1v7IXhYg1Z7m0X4dWZvLS_NU94HSk3sQjxIJdQdDsL3v2lA7qZb8kMJtOgaTQmbgchdPcS5lYJqDLnCPAgkPXX-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_ieLohOiSlAEI76ruI8lLm9b38Z1ezvYVrHb3eeD9a6Ud1Yqgzn8IItzwIO_ROV-mxCE1gD9wMLR12LFh7tHcM0sVrNDejc7P78-jCPEgZhszvHkZJmmD99VT8WjJN0ZW0eaTDqDctPINfONje_gI8SAsdNmLkgwo6C7sNlA0w5etqFtYinIUONRaoZsvKCL8AwjxIA2hV1vTaHnZ0H1C8QPNCa4zPF28I1WTprq_7EMWTmgNCPAgTIi7pTyOUloYbDo8jyi045qjrPOAUq1m63KiIzQgnioI8SCsPaknvtpl8xqUSQ375WqVAyNnnaFHf5R0P7tfqwlu9wjwIMH_9aFK1xnp4BXFZuvdPeSXUB5AoGY62wnaRIKCKFSbCPAgdC7SAy2fK-S3eSva7tx7owCrlOOu0_v14gC5EshI7qAI8SBFZ7nkuh-5IaK75jNF2I3u9gWIJeTINL1f_rXWP5TwxwjxIK8CKI34eu_sgR6N3zB1SKGijO7ko6-mgEUnS-DdScYBCP_wCOf1iajMfCj1CPAQnjpoz1kO_dN22pXdltGw2AjxIE4XykgsZ_WSh2vkwqZCzoJ33eOitoafeDpQ-3_6R7A_CPAg4b6CYztt395HgCIMw1-W5LfG-vu-JwtH6wIGvmq0bZwI8CCtU0WsKh5BwLGGWacTQHMeBHwdClkCV-rMMMXN9ZvwZQjxBGrRZZPwCNknZwX9zuTwAIPf4w0u-QyOLCtodHRwczovL2JvYi5idGMuY2FsZW5kYXIub3BlbnRpbWVzdGFtcHMub3Jn8Aj1kxLXPF3sgQjwEN3TRaAlnRGdywLUXJqL_hoI8SC_EwWue7sXTkhbkg2KtpDc5URgyM3Hol8HHDVDiM8uLgjxBGrRZZLwCDbPE8C0jkmw_wCD3-MNLvkMji4taHR0cHM6Ly9hbGljZS5idGMuY2FsZW5kYXIub3BlbnRpbWVzdGFtcHMub3JnCPEgcCe_goUV_i6JgQUm8vGIzFLLPxWjAk_iuhN8MP2HtsgI8CCPm2C9s0XubFI_iMYYTrp7NQVEucjiDVVOS-5XhW0I8AjwILGVzUe4o5G4eCfsNghhwOFziij306RNYES910HKmhrsCPAgVyONoXyQM0NgJkZo0hKVGO9f4juKf5A3CyvglhBsUm8I8CCeXSTiCzsu5jmLW6aIc74nszLe4FOEslRZChj0t1VKtAjxIDr4W3XX8r8aow1ZiGRWxWoIW9dJhunhLwmguwsGdTO-CPEgELz-YATskE_flI3EMFwbuOgsnBRGkzF1Xa9I7rj-MQ4I8SB7TgKiPXFKLsITxTCqIEY2E_JnlB0P9hnCf6F5J05tTgjxIGB0NKCvdVTHWPyb-krv47MzDAWBd4vLje6N98K_6F_kCPAgyX4-cC3jGOgERVTj6eTI3Q0pFr0C9fiQQx-WUXIglL0I8VkBAAAAAfPitX67BAWDTZtWcQxQWCkh0YqMzi1a4gPWRNWeuOKwAAAAAAD-____AlREAgAAAAAAFgAUEXKzahzT5T5tisLdW6UYvM0Pl9sAAAAAAAAAACJqIPAEctMOAAgI8SAwkgFiLjrE4i4UPDMn2c7HXieBbkduCVR_rk5GmSghhwgI8CAeAZYQYIMdaCxzBP3Y06gnuz57Ns-TKJavZGdhkML93AgI8CC198zLIu74yxwmwNzR3PAaynBKuua9UCcw2CyBaEcKWAgI8CAxSXU58ENTCGnlVmMfBUDSe7PUXkdlNQkIcCczUvUXcwgI8CBK0rtRametS55XkRoTu4TTLoEsynoQA2atuGtOoQFm7wgI8CDktVbsge1QvmY068_HWE5N8syaqVDu30QVb4oO2shIhAgI8CAAGBdnq6kVTyqINAoW1AWmqSMrCXQ-zEzglSNUuUMpuQgI8CATBv3oWI6GOVvAjwYVlDhrkZfDGzhtR2pU4wqu0FZXfQgI8SCoGD7CnRzwIA9X2TonvAhr38a1B-laaGkTXOoVnKLalAgI8CDalktNU8YluuKLPRSEzK1gNVgBc6BCdYNysw57Ar07xwgI8SDGbdDDNu9PiyInO5tAadJPrtta_57FjBI8_UoOLsJpTAgI8SCbq51S51-NRozSBQVPKUoYMzKmPum0xMbTObF39PnJNwgI8CAyk4ieSMUJWnWk5mF9mfI8CXyF1YaYfNBysYuAvBIouAgIAAWIlg1z1xkBA_OmOw"]},"log":{"leaf_index":"2492","tree_size":"3804","proof":["cb155c829a002e2bfdc9a445555f0af100f037b0e3ae515ef94df0fddb234e89","25d6f1270b5e8e97142dfc7c66d1dcf32d49e40569c6634f9dab266ffd81c817","90316440379185d22cf4b9775a965c0ce239dd538bbb217d871f67b1d80f19d6","5a529064d951f1c8b241d052eb822ec2082867e789958497301cf4ef0c84cf2a","cbc2831e5b6970668a5c25d96212437dc080ce433db09e906381d4be69cd52a4","75d62c26dd2083a68ca87ffe7e4f3a02109d74ea4f6b1fb2e07b3a08cf3fee64","ee9896b363c1f877f7d4613cda248fa64d56c7d8dd814ac0aef5244e9bfb1f00","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\nd9266dfc4cd2298dd267a2b8aa91c4328de4b61fe6506c1f6847ad08e4afd8c3\n2492\n2026-10-15T23:43:57Z\n2026-10-16T01:43:57Z\n\n— pubphys.com/log/v1 JFPwION/qxtG6WhIn4QDgqAmDMtUdXWQHrUKkYPIQnHbjJNqTeNGQPQ7xYSJ49ZX/58AuFd+00LvwgN+XzzkQV9AEQw=\n"},"orcid_key_evidence":[],"attesting":null}