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EXAMINATION FOR RADIO-ACTIVITY OF FIVE COMPLAINANTS AGAINST THE
UNITED STATES RADIUM CORPORATION
by
DR. FREDERICK B. FLINN AND DR. HERMAN SCHLUNDT.
The object of the tests made was to detect the presence of radioactive
substances - radium and mesothorium - in bodies of the complainants.
The examination was conducted in Dr. Martland's office in the City
Hospital, Newark, on Sunday, April 22, 1928. The tests were made jointly
by Dr. Flinn and myself.
Experimental Method: Measurements were made by means of a very sen-
sitive gamma ray electroscope with quartz fiber mounting. Each person was
tested for radio-activity by placing the electroscope close to the middle of the
back, the person being seated in a chair. Before testing the person the
natural drift of the instrument was first carefully taken, by both Dr. Flinn
and myself working independently. The person under examination was then seated
in a chair close to the instrument and readings of the drift were again taken by
each observer independently. (We may remark here that Dr. Goetler and Mrs.
Hughes, observers for complainants, also made readings on our instrument while
the tests were in progress, but their readings were made entirely independent
of our own, and we have no knowledge of the results they recorded.) After
two independent sets of readings had been taken by us, the person under test was
excused, and the natural drift of the testing instrument was taken again, before
the next test was made on the next person. We wish to emphasize one point in
this procedure, namely that between each test on the persons examined we tested
the natural leak or drift of the testing electroscope. Making the tests in
this way we can detect at once any slight changes in the behavior of the testing
electroscope. Then too we wish to point out that all readings were taken over
approximately the same part of the scale of the instrument.
Page -2-
Test on Miss Grace Freyer: The first person tested by this method was Miss
Grade Freyer. The natural drift of the instrument before readings were made
with Miss Freyer in the chair close to the electroscope, was found by Dr. Flinn
as 10 divisions of the scale in 11 min 2 sec., or 0.01510 divisions per second,
Independent readings by Schlundt gave a natural drift of 0.01484 divisions per
second. The average of these very closely agreeing values is 0.01497 divisions
per second (d.p.sec.) Directly after these readings Miss Grace Freyer was
seated in the chair with her back close to the instrument and readings of the
drift were again taken by each of us. The value found by Flinn was 0.01510
d.p.sec., by Schlundt 0.01504, again very closely agreeing values, and what is
all important, that the average of these two readings, 0.01507, is far within
the limits of experimental error, the same as the natural drift.
Miss Freyer's posture was then changed SO that she faced the testing
electroscope, which was then in front of her opposite her breast. Two inde-
pendent readings were again made, as given in the following table:
Drift
Observer
Scale divisions
time
Divisions per second.
Flinn
61 - 50 (11)
12' - 18''
0.01491
Schlundt
59 - 49 (10)
11' - 10"
0.01493
Average
0.01492 divisions per second
The natural drift of the instrument was then taken again, and found to be as follows:
Drift
Observer
Scale Divisions
time
Divisions per second
Flinn
69 - 64 (5)
5' - 26''
0.01534
Schlundt
67 - 61 (6)
6' - 32''
0.01531
Average
0.01533 divisions per second
Now let us summarize these tests:
Page - 3 -
1. Natural drift of testing electroscope before test-
0.01497 d.p.sec.
2. Drift, Miss Freyer, electroscope at back
0.01504 " 11 "
3. Drift, Miss Freyer, electroscope at breast
0.01492 " 11 11
4. Natural drift, directly after Miss Freyer was tested
0.01533 14 18 "
5. Average of two tests on Miss Freyer
0.01498 " " 11
6. Average of Natural drifts, before and after test
0.01515 19 11 11
From lines 5 and 6 of this table it is evident that radioactivity was not detected
in Miss Grace Freyer, In other words the test was absolutely negative. That
is with Miss Grace Freyer in chair the drifts of instrument averages 0.01498 d.p.sec
and the natural drift is 0.01515. Difference is - 0.00017 d.p.sec.
Test on Mrs. McDonald: The test was made in the same manner as described above
for Miss Freyer. The experimental results are summarized in the following table:
Test on Mrs. McDonald.
1. Natural drift of testing electroscope before test
0.01533 d.p.sec.
2. Drift with Mrs. McDonald near testing electroscope
0.01541 " 11 11
3. Natural drift of testing electroscope after test 0
0.01494 " 11 **
4. Average of natural drifts before and after
0.01514 " 11 11
The foregoing table clearly shows that no radio-sctivity was detected in
Mrs. McDonald. This conclusion is evident, when we focus attention on the prac-
tically identical values for the drift on Mrs. McDonald and the natural drift
- 0.01541 and 0.01514, a difference of only.0003 d.p.second, which is + 0.0003
unquestionably within the limit of error of the testing instrument.
Page - 4- -
Test for Radio-activity of Miss Schaub.
The same kind of test was made on Miss Schaub. The experimental results
are summarized in the following table:
1. Natural drift of testing electroscope before test
0.01514 d.p.sec.
2. Drift with Miss Schaub near testing electroscope
0.01445 d.p.sed.
3. Natural drift of testing electroscope after test
0.01445 11 11 "
4. Average of natural drifts
0.01480 " If "
Again we note that the difference between the natural drift and the
drift on Miss Schaub is fully within the limit of experimental error, and is
negative, 0.01445 - 0.01480 = - 0.00035
Test for Redioactivity on Mrs. Larice
1. Natural drift before
0.01445 d.p.sec.
2. Drift with Miss Larice near testing electroscope
0.01512 11 If 11
3. Natural drift after test
0.01600 If If If
4. Average of natural drifts
0.01522 If # If
Difference .01512 .01522 = - 0.0001
Test for Radioactivity on Mrs. Hussman
1. Natural drift before test
0.01600 d.p.sec.
2. Drift with Mrs. Hussman near instrument
0.01608 11 " if
3. Natural drift after test
0.01397 11 17 11
The marked change in the natural drift is abnormal and exceeds the ex-
perimental error under normal conditions. We therefore requested that another
test be made. Unfortunately Mrs. Hussman had left the building after being told
to wait. The test on Mrs. Hussman we therefore consider unfinished, and we are
not in position to say whether or not she is radioactive.
Page - 5 -
How sensitive is this gamma ray method of detecting radioactive substances?
We have arrived at the conclusion that the presence of 10 micrograms of radium (or
mesothorium) can be detected with certainty under the conditions at the time we
made our tests. Under more favorable conditions, such as exist in a regular
testing laboratory, perhaps an amount of radium as small as 5 micrograms will
regularly show an increase in the drift of the instrument, and this amount of
radium may thus be considered the limit of detection by this method.
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"ocrText": "EXAMINATION FOR RADIO-ACTIVITY OF FIVE COMPLAINANTS AGAINST THE\nUNITED STATES RADIUM CORPORATION\nby\nDR. FREDERICK B. FLINN AND DR. HERMAN SCHLUNDT.\nThe object of the tests made was to detect the presence of radioactive\nsubstances - radium and mesothorium - in bodies of the complainants.\nThe examination was conducted in Dr. Martland's office in the City\nHospital, Newark, on Sunday, April 22, 1928. The tests were made jointly\nby Dr. Flinn and myself.\nExperimental Method: Measurements were made by means of a very sen-\nsitive gamma ray electroscope with quartz fiber mounting. Each person was\ntested for radio-activity by placing the electroscope close to the middle of the\nback, the person being seated in a chair. Before testing the person the\nnatural drift of the instrument was first carefully taken, by both Dr. Flinn\nand myself working independently. The person under examination was then seated\nin a chair close to the instrument and readings of the drift were again taken by\neach observer independently. (We may remark here that Dr. Goetler and Mrs.\nHughes, observers for complainants, also made readings on our instrument while\nthe tests were in progress, but their readings were made entirely independent\nof our own, and we have no knowledge of the results they recorded.) After\ntwo independent sets of readings had been taken by us, the person under test was\nexcused, and the natural drift of the testing instrument was taken again, before\nthe next test was made on the next person. We wish to emphasize one point in\nthis procedure, namely that between each test on the persons examined we tested\nthe natural leak or drift of the testing electroscope. Making the tests in\nthis way we can detect at once any slight changes in the behavior of the testing\nelectroscope. Then too we wish to point out that all readings were taken over\napproximately the same part of the scale of the instrument.\nPage -2-\nTest on Miss Grace Freyer: The first person tested by this method was Miss\nGrade Freyer. The natural drift of the instrument before readings were made\nwith Miss Freyer in the chair close to the electroscope, was found by Dr. Flinn\nas 10 divisions of the scale in 11 min 2 sec., or 0.01510 divisions per second,\nIndependent readings by Schlundt gave a natural drift of 0.01484 divisions per\nsecond. The average of these very closely agreeing values is 0.01497 divisions\nper second (d.p.sec.) Directly after these readings Miss Grace Freyer was\nseated in the chair with her back close to the instrument and readings of the\ndrift were again taken by each of us. The value found by Flinn was 0.01510\nd.p.sec., by Schlundt 0.01504, again very closely agreeing values, and what is\nall important, that the average of these two readings, 0.01507, is far within\nthe limits of experimental error, the same as the natural drift.\nMiss Freyer's posture was then changed SO that she faced the testing\nelectroscope, which was then in front of her opposite her breast. Two inde-\npendent readings were again made, as given in the following table:\nDrift\nObserver\nScale divisions\ntime\nDivisions per second.\nFlinn\n61 - 50 (11)\n12' - 18''\n0.01491\nSchlundt\n59 - 49 (10)\n11' - 10\"\n0.01493\nAverage\n0.01492 divisions per second\nThe natural drift of the instrument was then taken again, and found to be as follows:\nDrift\nObserver\nScale Divisions\ntime\nDivisions per second\nFlinn\n69 - 64 (5)\n5' - 26''\n0.01534\nSchlundt\n67 - 61 (6)\n6' - 32''\n0.01531\nAverage\n0.01533 divisions per second\nNow let us summarize these tests:\nPage - 3 -\n1. Natural drift of testing electroscope before test-\n0.01497 d.p.sec.\n2. Drift, Miss Freyer, electroscope at back\n0.01504 \" 11 \"\n3. Drift, Miss Freyer, electroscope at breast\n0.01492 \" 11 11\n4. Natural drift, directly after Miss Freyer was tested\n0.01533 14 18 \"\n5. Average of two tests on Miss Freyer\n0.01498 \" \" 11\n6. Average of Natural drifts, before and after test\n0.01515 19 11 11\nFrom lines 5 and 6 of this table it is evident that radioactivity was not detected\nin Miss Grace Freyer, In other words the test was absolutely negative. That\nis with Miss Grace Freyer in chair the drifts of instrument averages 0.01498 d.p.sec\nand the natural drift is 0.01515. Difference is - 0.00017 d.p.sec.\nTest on Mrs. McDonald: The test was made in the same manner as described above\nfor Miss Freyer. The experimental results are summarized in the following table:\nTest on Mrs. McDonald.\n1. Natural drift of testing electroscope before test\n0.01533 d.p.sec.\n2. Drift with Mrs. McDonald near testing electroscope\n0.01541 \" 11 11\n3. Natural drift of testing electroscope after test 0\n0.01494 \" 11 **\n4. Average of natural drifts before and after\n0.01514 \" 11 11\nThe foregoing table clearly shows that no radio-sctivity was detected in\nMrs. McDonald. This conclusion is evident, when we focus attention on the prac-\ntically identical values for the drift on Mrs. McDonald and the natural drift\n- 0.01541 and 0.01514, a difference of only.0003 d.p.second, which is + 0.0003\nunquestionably within the limit of error of the testing instrument.\nPage - 4- -\nTest for Radio-activity of Miss Schaub.\nThe same kind of test was made on Miss Schaub. The experimental results\nare summarized in the following table:\n1. Natural drift of testing electroscope before test\n0.01514 d.p.sec.\n2. Drift with Miss Schaub near testing electroscope\n0.01445 d.p.sed.\n3. Natural drift of testing electroscope after test\n0.01445 11 11 \"\n4. Average of natural drifts\n0.01480 \" If \"\nAgain we note that the difference between the natural drift and the\ndrift on Miss Schaub is fully within the limit of experimental error, and is\nnegative, 0.01445 - 0.01480 = - 0.00035\nTest for Redioactivity on Mrs. Larice\n1. Natural drift before\n0.01445 d.p.sec.\n2. Drift with Miss Larice near testing electroscope\n0.01512 11 If 11\n3. Natural drift after test\n0.01600 If If If\n4. Average of natural drifts\n0.01522 If # If\nDifference .01512 .01522 = - 0.0001\nTest for Radioactivity on Mrs. Hussman\n1. Natural drift before test\n0.01600 d.p.sec.\n2. Drift with Mrs. Hussman near instrument\n0.01608 11 \" if\n3. Natural drift after test\n0.01397 11 17 11\nThe marked change in the natural drift is abnormal and exceeds the ex-\nperimental error under normal conditions. We therefore requested that another\ntest be made. Unfortunately Mrs. Hussman had left the building after being told\nto wait. The test on Mrs. Hussman we therefore consider unfinished, and we are\nnot in position to say whether or not she is radioactive.\nPage - 5 -\nHow sensitive is this gamma ray method of detecting radioactive substances?\nWe have arrived at the conclusion that the presence of 10 micrograms of radium (or\nmesothorium) can be detected with certainty under the conditions at the time we\nmade our tests. Under more favorable conditions, such as exist in a regular\ntesting laboratory, perhaps an amount of radium as small as 5 micrograms will\nregularly show an increase in the drift of the instrument, and this amount of\nradium may thus be considered the limit of detection by this method."
}