. CECPET —o Our flight pattern (and this is where the term "early" comes in) will be based on a report of the closest YAG when fallout has been completed. At that time we plan to circle around zero at approximately 20 miles out. This will give us the main fallout pattern. From our limited experience on CASTLE, which was a rush program at that point, we found a pattern which could be referred quite possibly to the stem, so this pattern will indicate both positive and negative information. The positive information is that it went where we think it did; the negative information is that it did not go in the other direction. In addition, as it is cleared, the roll-out of the fallout, the other planes will probably work a circle between 40 and 50 miles to correlate with the first YAC, Flight patterns will be carried out as long as possible on D-Day. On D$él we plan to completely delineate the area no matter where it may take us (even to Hawaii, I hope). On D}2 we want to repeat the pattern to study the dispersion horizontallyof the pattern and also to correlate back to give us two measurements. Again, we would like to repeat this on D4. There may be a requirement (and operationally we want to be geared for this) that if the pattern is still markedly present we would fly a day or two before it was expected to fire another shot - in this case so we could see what was added on. The four day flight would tell us whether this is decaying down or dispersing; with this it might not be absolutely necessary to fly the preeshot flight, but operationally, we want to remain geared to thia, If we find a stem pattern, one plane will be sent up to follow it. This aircraft will contain a radiation detector with altitude compensation and a tele- meter to telemeter the radiation data instantaneously back to the plot center. At the plot center this information will be received along with plane location to build up a progressive plot. In addition we want to put in the ship information and all information that is available to correlate at the time. Another radio channel will be used in common to the two navigators of the two aircraft we're working with to control their pattern. If we find an indicatio from an island station report we certainly want to get some aerial coverage down in this direction. This is more of a Rad-Safe requirement; however, it still does exist. This is primarily to provide tactical information as well as to coordinate the measurements with surface measurements so that we can in the future just fly the airplane. We have two small phases of the program which are a study of instrumentation techniques. We want to correlate gamma spectra measurements made by helicopter with the same information from below the surface of the sea as measured by the YAGs, Any questions? Q: How badly is your instrument hurt by contamination of the aircraft? A: We shield the detector so that it only sees a 90° view. It is so located in the aircraft that it is as far as possible from any leading edge, ee LANL RC This is where