{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2017:7B4KKAECLQMD7XKCNQJBKDSNXE","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":"7560bfbe61f0ffef329408ae8723d3a041df9a33e5bba05cce5f86a30d4bd9cd","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.ins-det","submitted_at":"2017-07-20T08:27:21Z","title_canon_sha256":"a256f5f28b69a3f7779fa33796f13cbe12a10f4dccf70fd99f12430d40a2ae1c"},"schema_version":"1.0","source":{"id":"1707.06413","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1707.06413","created_at":"2026-05-18T00:26:29Z"},{"alias_kind":"arxiv_version","alias_value":"1707.06413v2","created_at":"2026-05-18T00:26:29Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1707.06413","created_at":"2026-05-18T00:26:29Z"},{"alias_kind":"pith_short_12","alias_value":"7B4KKAECLQMD","created_at":"2026-05-18T12:31:03Z"},{"alias_kind":"pith_short_16","alias_value":"7B4KKAECLQMD7XKC","created_at":"2026-05-18T12:31:03Z"},{"alias_kind":"pith_short_8","alias_value":"7B4KKAEC","created_at":"2026-05-18T12:31:03Z"}],"graph_snapshots":[{"event_id":"sha256:10d783bcc38b1db48706291f329bea711a4affdd8f8f8656b0ff5f5bee138d95","target":"graph","created_at":"2026-05-18T00:26:29Z","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":"We established a method to assay $^{210}$Pb and $^{210}$Po contaminations in the bulk of copper samples using a low-background alpha particle counter. The achieved sensitivity for the $^{210}$Pb and $^{210}$Po contaminations reaches a few mBq/kg. Due to this high sensitivity, the $^{210}$Pb and $^{210}$Po contaminations in oxygen free copper bulk were identified and measured for the first time. The $^{210}$Pb contaminations of our oxygen free copper samples were 17-40 mBq/kg. Based on our investigation of copper samples in each production step, the $^{210}$Pb in oxygen free copper was understo","authors_text":"A. Takeda, B. D. Xu, B. S. Yang, G.Kanzaki, H. Ogawa, H. Sekiya, H. Takiya, K. B. Lee, K. Fushimi, K. Hiraide, K. Hosokawa, K. Ichimura, K. Kanzawa, K. Kobayashi, K. Martens, K. Masuda, K. Miuchi, K. Nishijima, K. Sato, M. K. Lee, M. Kobayashi, M. Miyasaka, M. Nakahata, M. Yamashita, N. Oka, N. Y. Kim, O. Takachio, R. Fujita, R. Kegasa, S. Moriyama, S. Nakamura, S. Tasaka, T. Norita, XMASS Collaboration: K. Abe, Y. D. Kim, Y. Fukuda, Y. H. Kim, Y. Itow, Y. Kishimoto, Y. Suzuki, Y. Takeuchi","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.ins-det","submitted_at":"2017-07-20T08:27:21Z","title":"Identification of $^{210}$Pb and $^{210}$Po in the bulk of copper samples with a low-background alpha particle counter"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1707.06413","kind":"arxiv","version":2},"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":"sha256:6370326ef6e8e8319e8a52d6e1c6ce236c9ad5f026df5892664d6b4900d02c4e","target":"record","created_at":"2026-05-18T00:26:29Z","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":"7560bfbe61f0ffef329408ae8723d3a041df9a33e5bba05cce5f86a30d4bd9cd","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.ins-det","submitted_at":"2017-07-20T08:27:21Z","title_canon_sha256":"a256f5f28b69a3f7779fa33796f13cbe12a10f4dccf70fd99f12430d40a2ae1c"},"schema_version":"1.0","source":{"id":"1707.06413","kind":"arxiv","version":2}},"canonical_sha256":"f878a500825c183fdd426c12150e4db9151d6705a7b6d1b02b3a672f38a77c24","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"f878a500825c183fdd426c12150e4db9151d6705a7b6d1b02b3a672f38a77c24","first_computed_at":"2026-05-18T00:26:29.596215Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:26:29.596215Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"J0ow3b4+Oo1paCYoLHu6W3YIWMwqGLeZXCoKwivoZrbYsS4ZvcCmmutInsJdcskKQDoZ1+Mu8J5es91XO7tuCg==","signature_status":"signed_v1","signed_at":"2026-05-18T00:26:29.596825Z","signed_message":"canonical_sha256_bytes"},"source_id":"1707.06413","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:6370326ef6e8e8319e8a52d6e1c6ce236c9ad5f026df5892664d6b4900d02c4e","sha256:10d783bcc38b1db48706291f329bea711a4affdd8f8f8656b0ff5f5bee138d95"],"state_sha256":"7be61748d236301a57da76fcc03a40aa76197da1f19a768929b66e4c9a87525f"}