. Journal of radiology . d op-posite the windows in the tin can elec-troscope in order that the rate of fallof the gold leaf might be observed andrecorded by means of a electroscope was connected tothe ionization chamber by an enameledcopper wire mounted in sulphur at theends and supported by cylinders ofparaffin in the metal tubing. This elec-troscope discharged ten small units inseven minutes, so that it was necessaryto make a correction for the readingsobtained. Fig. 1 shows a photograph ofa newer measuring apparatus inwhich the electroscope is more com-pletely enclosed by me
. Journal of radiology . d op-posite the windows in the tin can elec-troscope in order that the rate of fallof the gold leaf might be observed andrecorded by means of a electroscope was connected tothe ionization chamber by an enameledcopper wire mounted in sulphur at theends and supported by cylinders ofparaffin in the metal tubing. This elec-troscope discharged ten small units inseven minutes, so that it was necessaryto make a correction for the readingsobtained. Fig. 1 shows a photograph ofa newer measuring apparatus inwhich the electroscope is more com-pletely enclosed by metal and the cop-per wire is supported by sulphur cylin-ders throughout. This instrument willnormally discharge ten small units onthe scale in about three hours and canbe used without making a correctionfor the normal fall. The tank is ofsuch size that it can be carried ina hand bag. The ionization chamberis mounted on half inch pipe tightlyscrewed together so that it can be 169 IONIZATION MEASUREMENTS OF X-RAYS—ERSKINE. Figure I.—Photograph of Measuring Apparatus. requires 23 secondsto produce a fall often small units onthe scale with the immersed in water without any dangerof the inside of the chamber becomingdamp. The following results obtained frommeasurements of the surface and depthdoses with the technique used in myoffice two years ago, will illustrate themethods used in accumulating the fixed factors were 140 kv. 5 ma.,anode-surface distance cm., sur-face depth distance 10 cm., anddiameter of field cm. The averagenumber of seconds required to dis-charge ten small units on the scale withthe ionization chamber at the surface ofthe water was , while the averagenumber of seconds required to dis-charge ten small units on the scale withthe ionization chamber at the depth of
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Keywords: ., bookauthoramerican, bookcentury1900, bookdecade1920, bookyear1922
