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Machine-read from the scan, so expect some errors. Lines that couldn’t be read are left out.
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CALIFORNIA, RAMATION LMORA 1’ORY,HE4LTH PHYSICS group put into operation the necessary equipment to maisebackground measurements of the ~escri~tion of Eauiument and Zetnods used Two Victoreen thin wall Al. Geiger tubes were employed to sample the outside atmosphere. The Geiger tubes were mounted at the end of a plastic cylinder whose measurements were 8t in length and 6R in diameter. Outside air was drawn through the plastic cylinder and sampled by the Geiger tubes. One Geiger tube was connected to a counting rate meter which in turn was connected to an Esterline Angus recorder. The second Geiger tube was connected to a conventional scaler and register. Samples of rainwater were also collected and processetiin the following manner: The sample was collected from the roof of one of the Laboratory buildings by means of attaching a 5 gallon receptacle to a convenient down-spout. The sample was then filtered through several pieces of ,#40Whatman filter paper. The paper was ashed and an aliquot was evaporated onto a counti~ plate. The plate was counted with an end window Geiger tube connected to a scaler and register. .Priorto taking the rain samples the roof was washed down several times for twc reasons. First to remove any contamination and seconuly to establish some sort of a normal background for this particular roof. On two occasions the Geiger tubes indicated an increase in background. The dates and times are as followst of the above increases were detected by,the HealthBoth known filter paper method to sample the air (see Health Chemistry group using the well
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Samples of rainwater were taken at the following times: No significant increase in background was detected taken from April 14, 1951 through June 15, 1951. in any of the rain semples. Data was