Ask the Scholar

{
    "localId": "75722589",
    "label": "Report, April 25, 1928",
    "core": "doc",
    "dtoType": "document",
    "citationUrl": "https://catalog.archives.gov/id/75722589"
}

{
    "id": "75722589",
    "sourceUrl": "https://catalog.archives.gov/id/75722589",
    "contentType": "document",
    "title": "Report, April 25, 1928",
    "citationUrl": "https://catalog.archives.gov/id/75722589",
    "collections": [
        "Safety Light Collection",
        "Records Related to Radium Dial Painters"
    ],
    "iiifBase": "https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/SLC/Radium/SLC_0001279_Page_1.jpg",
    "thumbnailUrl": "https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/SLC/Radium/SLC_0001279_Page_1.jpg",
    "largeImageUrl": "https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/SLC/Radium/SLC_0001279_Page_1.jpg",
    "imageCount": 5,
    "hasImages": true,
    "source": "import",
    "hasTranscription": false
}

{
    "url": "https://catalog.archives.gov/id/75722589",
    "naId": 75722589,
    "levelOfDescription": "fileUnit",
    "recordType": "description",
    "ocrSource": "nara-archive"
}

{
    "seq": 5,
    "pageIndex": 0,
    "type": "document",
    "url": "https://s3.amazonaws.com/NARAprodstorage/lz/electronic-records/SLC/Radium/SLC_0001279.pdf",
    "mediaId": "cb0441fbbe04e069",
    "ocrText": "Missellaneous Experiments Conducted in Dr. Flinn's Laboratory,\nCollege of Physicians and Surgeons, 168th Street, New York,\nNew York, April 25, 1928\nby\nDr. F. B. Flinn and Herman Schlundt.\nSensitiveness of the Wulf quartz-fiber electroscope when used as a gamma ray in-\nstrument: The natural drift of the instrument was taken first: Results--\n70-65 sub divisions of scale 9' - 54'' (Schlundt) or 0.00842 d.p.sec.\n69-54 11\n11\n11 11 10'- 6'' (Flinn) or 0.00825 d.p.sec.\nAverage\n0.00838 d.p.sec.\nDr. Flinn then seated himself in a chair so that the instrument was\nclose to the middle of his back. He held in his hand in a vertical position a\nstandard of 10 micrograms (solution) of radium contained in a sealed glass nearly\n3 feet long. The liquid in the tube measures 31 inches, and the tube is 20 mm\nexternal diameter. Readings of the drift were again taken, this time by Schlundt\nalone.\n66 - - 56 divisions in 18' - 13'' or 0.00915 d.p.sec\nSubtracting natural drift\n0.00838 11 11 11 we get a net\nincrease of\n0.00077 11 11 it\nSchlundt then exchanged places with Flinn but he did not hold the radium\nstandard.\n64 - 59 Divisions in 9' - 32'' = 0.00874 d.p.sec.\nThe natural drift with no one in chair was then taken.\nFlinn\n58 - 53 in 9' - 27'' or 0.00882 d.p.sec.\nSchlundt\n57 - 51 in 11'- 44\" or 0.00852 \" ** \"\nAverage 0.00867 11 if 11\nThis value subtracted from the drift with Schlundt in chair shows a net increase\nof only 0.00007 d.p.sec., a value safely within the limit of experimental error.\nThe result shows that Schlundt is not radioactive.\nPage - 2 - -\nThe two 5 micro ampoules of radium solution were put in Schlundt's\nvest pockets as he sat in chair with back to electroscope, and readings were ma de\nby Flinn.\n71 66\n9' - 15''\n71 - 63\n18' - 5'' or 0.00922 d.p.sec.\nDeducting natural drift\n0.00867 \" \" If leaves a net\nincrease of\n0.00055 11 If If\na value slightly less than was obtained in the earlier experiment with Dr. Flinn\nin chair. The natural drift was then taken again by both observers:\nSchlundt\n68 - 44\nin\n48' - 28''\nor\n0.00824 d.p.sec.\nFlinn\n67 - 45\nit\n44'- 20''\n19\n0.00827 d.p.sec.\nAverage\n0.00825 \" \" \"\nSchlundt in chair without Radium standard = .00874 d.p.sec (see above). Deducting\nlast natural drift of 0.00825 leaves a positive effect due to 10 micrograms of\n0.00049 d.p.sec., as against 0.00077 for Flinn with 2 - 5 microampoules on his\nperson in the form of a long column of liquid.\nIs this difference due entirely to difference in form of standard used?\nAnswer: Only partly so, because in making measurements with standards in vest\npockets of Schlundt the tubes are a greater distance from instrument.\nAfter lunch we made another test to determine the radium content of the\nsample of expired air obtained about 20 hours before from Mrs. Dumschoff at Nau-\ngatuck.\n2730 cc of expired air was introduced into the ionization chamber, No.15\nU. S. Radium Corporation, the natural drift having been found first to be 0.0230 d.p.sec\nThe expired air was introduced at 3:50 and the first reading was made at 3:55,\n* 5 minutes later.\nAt 3:55\n90 - - 85\n2'- 55''\nor\n0.0286 d.p.sec.\n90- 78\n7'- 53'8\n11\n0.0253 \" 11 It\n77 - 67\n7'- 2''\n=\n0.0237 11 11 18\nPage 3 -\nAt\n4:15\n64 - - 54\n7' - 2''\nor\n0.0237 d.p.sec.\nAt 4:55\n80-65\n11' - 5''\nit\n0.0226 \" # #\nwhich is a value less than the original natural drift. Since no rise in drift\nwas noted, the test is obviously negative, and casts some doubt on the distinct\nincrease in discharge observed when the gas was first tested shortly after our\nreturn from Naugatuck. Perhaps the emenation had been absorbed in the meantime\nin walls of Duffel bag. This test on the activity of the expired air should be\nrepeated, since the emanating power of radium compounds deposited in bone depends\nupon this result (see other report).\nA Bit of Theory: Assume that we have a patient containing 1 microgram mesothorium,\nmeasured as radium equivalent, Further assume that in actual practice only one\npercent of thorium continually generated actually gets into the testing chamber with\nthe expired air. Question: How fast will be the resulting drift, assuming that\na current of dried expired air is continually passing thru the ionisation chamber?\nLet the constant of the instrument be taken as 10 x 10-9 curies per subedivision per\nsecond. The amount of thoron present in chamber will be 1% of 1 X 10⁻⁶ X 1.28\nX 10⁻² = 1.28 X 10⁻¹⁰ curies where 1 X 10⁻⁶ x 1.28 X 10-2 curies is the amount of\nthoron generated per second by 1 microgram mesothorium. If the ionization chamber\nhas a volume of 1000 cc it will have in it the thoron produced in 6 see and the\nobserved drift whould thus be that produced by 6 X 1.28 X 10⁻¹⁰ = 7.7 X 10⁻¹⁰ curies.\nSince a drift of 1 d.p.sec. is produced by 10 X 10-9 curies, the observed drift will\nbe\n7.7 X 10⁻¹⁰ = 0.077 d.p.sec.\n10 x 10-9\nand in the case of Mrs. Dumschoff whose expired air would be laden with 40 times\nthis quantity of thoron the observed discharge should be about 3.3 div. per sec.\nThis value appears to be hight but the experiment should be conducted several times\nwith Mrs. Dumschoff as subject. Some interesting data are in sight, which will\nshow that the presence of mesothorium can be more easily detected in the expired sir\nof a living person then the pres ence of Radon.\npage 4 -\nExperiments with more active source of gramma rays.\nA sample of radium containing\nmg Radium was placed 5 5/8 inches\nfrom the gamma ray instrument and readings of drift taken: The Lind instruments\none with large ionisation chamber, 4 liters capacity, and the other with half\nliter chamber were put in place of gamma ray machine, and readings taken. The\nresults are recorded in the following table:\nType of Instrument\nDrift 40 divisions\nGamma Ray (Wulf quartz fiber)\n:\n19.0 seconds\nLarge Lind\n:\n25.9 \"\nSmall Lind\n:\n93\n11\nThese tests show that the Lind machine with large chamber falls only a little\nshort of being as sensitive as the gamma ray (quarts fiber) instrument for\ndetecting radioactivity by the gamma ray method. The small Lind, when used as\na gamma ray instrument, is about 1/5 as sensitive as the Wulf quartz fiber.\nThe two 5 microgram ampoules were then in turn strapped to these instruments and\nreadings made. The results are recorded here in tabular form.\nType of Instrument\nDischarge of 10 divisions\nWulf quartz fiber\n:\n174\nseconds\nLarge Lind\n:\n218\nIf\nSmall Lind\n:\n836\n\"\nThe tests confirm the conclusion drawn from the previous test."
}