10% = Figure 5. 10° lon — \ol— EF oa SPECIFIC BETA ACTIVITY AT 25DAYS (ARBITRARY UNITS) T | T | 10° 1 lL 9 QO Oo © ° J ® DIAMETER (yum) 9 2 | | lo! 9° T LASSEN l Specific Activity of Some Particles of a Very Low-Yield Balloon Shot, 574 I } 7 —4 7 — = 10"