than twice this amount. The values are finally presented as histograms on which the stindarea GITR record corrected to 1 minute using the Standard decay curve (called the normalized rate curve) has been superimposed for ease of comparison (Figures 3.37 through 3.62). The plotted values may be converted to counts, min at 22 days by dividing by 0.015; the values mayalso be converted to GITR response to an infinite plane contaminated to the same degree by multiplying by 6. ” When comparing the GITR record with the IC collections, it should be remembered that the sequence in which the trays were exposed, and therefore the time of exposure, was determined from the order of the trayS upon recovery. Mechanical limitations of the IC itself cannot permut a time resolution better than =‘, minute for early collections, tncreasing to :4 minutes at the end of the tray sequence. Furthermore, difficulties experienced in the emergency re-arming for Wahoo resulted in a number of arming errors such as incomplete restacking or the loading of trays in improper numemcal sequence. In all cases of such difficulty, exposure time was adjusted to that which seemed most probable on the basis of field notes, and this fact is indicated on all plots of the data. The comparison of the IC and the GITR records at a given station is usually quite reasonable. The maximum possible contribution due to deposited radioactivity is usually less than 1 percent of the gross gamma record; thus, within the accuracy claimed for the GITR records, no correction for the contribution due to deposited radioactive material need be applied. The close-in stations, particularly on Shot Umbrella, show no pronounced deposition at the time of the dose rate peak. The known instrument bias under the high initial velocities of the base surge would preclude the collection of a representative sample in cases of light deposition. On both shots, the period of deposition from the base surge is usually short at the upwind and crosswind positions. The longest periods of deposition occur at the downwind positions; none, however, exceed 10 minutes during Wahoo or 7 minutes during Umbrella. The Wahoo histograms frequently show two peaks of deposited activity whereas those from Umbrella usually display a single peak. The rate of deposition is difficult to ascertain for depositions as short as those observed because of the large time increments of the IC collections. The histograms were terminated at 15 minutes although most of the coracles showed IC collections at later times when no remnant of the base surge can be reasonably postulated. In the few cases where decays were observed, theso late colicctions exhibited the characteristic water decay and were probably due to spray from radioactive water in the vicinity of the coracle. A series of prolonged IC collections in the target area prior to Wahoo indicates that approximately 300 cc,/day of ocean spray entered the IC port. The value given has been corrected for rainfall reported in the area during the period of exposure; however, salt analysis of the liquid collected indicates that this correction may have been low. A similar value would be expected for the Umbrella target area. The IC collections after 15 minutes were treated in exactly the same manner described for the other collections using the water decay curve. Collections significantly above background are presented without further discussion in Table 3.7. The [C collections are designated by the location of the collection, followed by a time indicating the time at which each l1-minute collection ceased. The abbreviation “cont” following the time designator indicates that the IC stuck at the tray in question; therefore, the tray was exposed continuously from 1 minute prior to the indicated time until the coracle was recovered. A more complete description of the symbols used in IC tabulations is given in Appendix D.2. Although station density fer the IC collection was very low, IC data was also used to estimate the total deposition over the target array. These estimates were made by mapping the total activity deposited from the base surge as determined by the IC collections and performing approximate isodeposition contours through these points. Total deposited activity in counts,min was determined over equal areas for both shots by numerical integration. Because no reliable depo- sition information existed at distances closer than 3,500 feet for Umbrella, an area of this radius was omitted from both summations. These calculated total depositions were then con- verted to fissions using the standard decay curve and the factor 3.73 x 10° fissions- counts per 11 Page 112 deleted.