oSNa x * St “ ™ . = ot vay OS ss . ~ s s og SS * ete EET ‘* a _ > . . . SR Ss) a te Nee . Bs aes SASS »% = Measurements are made by beta counting of ashed sa:ples,. Sr-90 estimates are made by theoretical calculations, assuming a cates of origin for the debris. The results are mapped in Fig. 1 for the United States, and in Fig. 2 for the rest of the world. In previous reports it was decribed how a factor of 1.6 was required to correct gummed film mixed fission product activity to agree with pot samples collected at HASL. This correction has been applied to gummed film results issued since that time for all stations. Several groups of results in this report would indicate that a much larger correction factor would be in order, but this is not necessarily true. It is believed that the low Sr-90 values calculated from gummed film activity are due to the incorrect arbitrary burst assignments used in the calculations. The recaleulations of the gummed film values will be done, but it will be some time before the results are available. Therefore, gummed film data in this report, particularly after May 1956, should be considered as minimum estimates, and may be low by a considerable factor.