{
  "annotation_id": "1a41494d-1d1e-41a1-af2a-cff06e858bcc",
  "date_created": "2026-03-02T18:00:46.302000Z",
  "date_modified": "2026-03-02T18:00:46.302000Z",
  "file_hash": "71c1a018378548d141c0d837b3a0d1759a1b1f93dc187f73cf784e021d82fe2e",
  "private": false,
  "record": {
    "abstract": "We demonstrate a new method for determining the 81Kr/Kr ratio in\nenvironmental samples based upon two measurements: the 85Kr/81Kr ratio measured\nby Atom Trap Trace Analysis (ATTA) and the 85Kr/Kr ratio measured by Low-Level\nCounting (LLC). This method can be used to determine the mean residence time of\ngroundwater in the range of 10^5 - 10^6 a. It requires a sample of 100 micro-l\nSTP of Kr extracted from approximately two tons of water. With modern\natmospheric Kr samples, we demonstrate that the ratios measured by ATTA and LLC\nare directly proportional to each other within the measurement error of +/-\n10%; we calibrate the 81Kr/Kr ratio of modern air measured using this method;\nand we show that the 81Kr/Kr ratios of samples extracted from air before and\nafter the development of the nuclear industry are identical within the\nmeasurement error.",
    "arxiv_id": "physics/0311118",
    "authors": [
      "X. Du",
      "R. Purtschert",
      "K. Bailey",
      "B. E. Lehmann",
      "R. Lorenzo",
      "Z. -T. Lu",
      "P. Mueller",
      "T. P. O\u0027Connor",
      "N. C. Sturchio",
      "L. Young"
    ],
    "categories": [
      "physics.atom-ph",
      "physics.geo-ph"
    ],
    "doi": "10.1029/2003GL018293",
    "title": "A New Method of Measuring 81Kr and 85Kr Abundances in Environmental   Samples",
    "url": "https://arxiv.org/abs/physics/0311118"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "88b4c114-4fc0-4a63-aeca-a9aba6680259",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}