UNCLASSIFh--. TCIR - 591 - TOTAL LINEAR ABSORPTION COEF) JC IENTS OF VARIOUS MEDIA FOR GAMMA RADIATION. John A. Pierce, Jr. and Paul M. James, 6 November 1951. UNCLASSIFIED . ’ (uv) Total absorption coefficients for yimma radiation were determined on which no pertinent dat had previously been availmaterials four for able: methylecrylate, 100-octane gasoline, NT, and tritional; determined to be 0.0696, 0.0343, 0.0924, and 0.1055 per cM, respectively. The method (1.1 Mev) ina employed in these determinations involved the use of Ta gacma gun for collimation of the rays, and the subsequent application of the exponential attenuation law, I = Ige7#*. To vheck the accuracy of the determinations, absorption coefficients were #150 calculated for seven other materials on which data were already available in the literature. The presently determined results checked closely with published data on these seven raterials, thus indicating the accuracy of the method employed. TCIR - 606 - RADIOLOGICAL CLOTHING MONITOR. H. B. Martin, 27 November 19)0. UNC LASS IFIED . (uU) The device described here is a clothing monitor which permits measurement of the total radioactivity on a single garment in a single opere- tion. It consists of a table having a copper screen top, ¢7 by 29 inches. Irmedietely below the top are mounted five 12-inch, thin-wall G-M tubes arranged in such a manner as to monitor the are@ completely. A hinged lid contairs five additional G-M tubes behind a similar protective screen, so arranged that when the lid is closed the tubes in the two sections are perpeniicular to each other at their approximite midsections. A scaler, a register (recorder), and an automatic timer, together with a suitable scurce of high-voltage current, constitute the remaining equipmert for tke apparatus. Due to the simultaneous operution of ten teses;—the-back=-ground for the device is relatively high, this background being reducible only at the expense of sensitivity. For this reason, a total count of twice background has been set as the tolerance level above which a garmert is corsidered unwearable. UNCLASSIFIED LARGO n