Table 1 Activities of 134Cs,137Cs, 90Sr, 239+240Pu and 241Pu, atom ratio of 240Pu/239Pu and 241Pu/239Pu and radioactivity ratio of 134Cs/137Cs, 90Sr/137Cs, 239+240Pu/137Cs and 241Pu/239+240Pu for the analysed radioactive particles (DPs and SP).

From: First determination of Pu isotopes (239Pu, 240Pu and 241Pu) in radioactive particles derived from Fukushima Daiichi Nuclear Power Plant accident

Radioactive particle

DP1

DP2

DP3

SP

Activity [Bq]

134Cs

214 ± 2

794 ± 4

679 ± 4

230 ± 1

137Cs

234 ± 1

887 ± 4

736 ± 4

224 ± 1

90Sr

0.171 ± 0.010

0.589 ± 0.034

Not measured*

0.0455 ± 0.0040

239+240Pu

(1.70 ± 0.20) × 10−5

(3.48 ± 0.45) × 10−5

(7.06 ± 0.57) × 10−5

<4.44 × 10−6

241Pu

<1.97 × 10−3

(4.10 ± 0.68) × 10−3

(8.10 ± 1.27) × 10−3

<2.23 × 10−3

Atom ratio

240Pu/239Pu

0.330 ± 0.077

0.415 ± 0.069

0.373 ± 0.045

—

241Pu/239Pu

—

0.178 ± 0.016

0.162 ± 0.028

—

Radioactivity ratio

134Cs/137Cs

0.915 ± 0.009

0.895 ± 0.005

0.922 ± 0.006

1.03 ± 0.01

90Sr/137Cs

(7.31 ± 0.43) × 10−4

(6.64 ± 0.39) × 10−4

—

(2.03 ± 0.18) × 10−4

239+240Pu/137Cs

(7.26 ± 0.86) × 10−8

(3.92 ± 0.51) × 10−8

(9.58 ± 0.78) × 10−8

<1.98 × 10−8

  1. 241Pu decay was corrected to 11 March, 2011. The activities of 90Sr are quoted from Zhang et al.41. The analytical error is based on 1σ counting statics. *This radioactive particle was not analysed for 90Sr in the previous study41.
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