TTTano rom no. 64 Ray scentconsists of_7_-pages. No.2 ofS... _é_..copies, Series, 47 — Office Memorandum ¢ UNITED STATES GOVERNMENT ACS ey 2 ER “ ° . TO : FROM : SUBJECT: SYMBOL: Walter D. Claus, Chief of Applied Bio Physics DATE: July 24, 1751 Branch, Division of Biology & Medicine, USAEC, MnO D. C. G. V. Beard, Director, Health Physics Division, Idaho U) [Lmob, erations Office (REPORT ON ATRBORNE ACTIVITY AT IDO AS RESULT OF "OPERATION GREENHOUSE" : JMS :mb As per your request this memorandum is a summary of our air monitoring operations in the Idaho Operations area. | K oo, Due to the high temperature inversion problem encountered here and the complete lack of previous background readings, we were __ somewhat at a loss to be able to get a very definitive type of indication except in the case of the heavier concentrations of activity. Due to this above difficulty we are certain that. we have failed to evaluate all of the activity’which,|we= undoubtedly received. ey We have worked closely with the Weathe# Bureau onthe-inversion1: ne problem so that we have an indication as to its time and intensity. © You will note a plot of the inversion data on the upper section of the Central Facilities graphs. This was the only station at which _.,, the inversion data was available. This inversion data has correlated quite well with our peaks of activity but a separation of the effects due to the inversion and abnormal radioactivity is impossible with ou limited data. All we have is an indication as to intensity and its time interval. - With the above difficulties in mind we felt that the only method , °° | for conclusively reading twice background was to note the ebb period (no inversion present). when the activity was found during these ~ periods to be near or above twice background, a report was sent to you as requested except in a few cases mentioned below. Normal background was assumed for all stations to be about 60 x 10* counts per hour or about 100 counts per minute. This had to be assumed on the basis of what could be determined on days of normal activity. Mi ae uu- 7" ay thchlgeBle a ELLED BY AUTHORITY 2 < DIAZOF DOE/OC S65Q@ 225 Wilkow ASiR oHv ~~ ap Bek denoterr : DOS ARCHIVES anaes a ena