10° T T T © L T T T | T T T T T SHASTA - Magnetic particles from sieve fractions 4 (300-1000pm) @ GREENHOUSE-2 SPECIFIC ACTIVITY (ARBITRARY UNITS) T © DIABLO - Randomly picked particles & TUMBLER-SNAPPER 7 ® GREENHOUSE- [ 9L¢ ] & GREENHOUSE-3 (4-210um) \ x SIMON 7 ‘ \o%— 4 r 4 L 4 \ ARITHMETIC \ 10! ° t~ MEAN — GEOMETRIC MEAN - 4 \ r 10° io° a 4 Figure 7. L | io! L \ 4 “ \ i a 10° f 1 DIAMETER (zm) | 10° 4 1 | 10* i at Specific Beta Activity of Particles from Several Tower Shots over a Large Size Interval. i0°