Sec. 7.11] 

 Table 27. The 



RADIOACTIVITY 181 



Natural Radioactive Series and Alpha Particlbs— (Continued) 



Isotope 



Symbol 



Half-life 



Range, 



cm in 



air 



Energy, 

 mev 



Actinium-uranium Series — {Continued) 



Protactinium 



^Actinium 

 ► Radioactinium 



•Actinium K* 

 Actinium X <- 



Actinon 



Actinium A 

 Actinium B 

 Actinium C 



'Actinium C •- 



► Actinium C"»~ 



Actinium D 4 — 

 (Lead) 



Pa 



Ac 

 RdAc 



AcK 



231 



227 

 227 



>2A 



AcX 223 



An 



AcA 

 AcB 

 AcC 



AcC 



AcC" 



AcD 

 (Pb) 



219 



215 

 211 

 211 



211 

 207 

 207 



3.2 X 10< y 



21 .7 y 

 18.9 d 



21 m 

 11.2 d 



3.92 s 



3.20 

 3.23 

 3.511 



(4.36) 



(4.17) 



84 1.83 X 10-3 s 



36 m 



2. 16 m 



2.0 X 10-3 s 

 4.71 m 

 stable 



692 

 240 

 14 



45 7 



4.69 

 4.72 

 5.00 

 5.0 



5 . 429 

 4.984 



6.555 



051 

 019 

 990 

 968 

 924 

 870 

 817 

 766 

 744 

 719 

 674 

 /3" 



719 

 607 



533 



8235 



561 



436 



365 



0" 



618 



272 



7.680 



Velocity 

 3 X 10>° 

 cm /sec 



Disinte- 

 gration 

 energy, 

 mev 



0569 

 0.0567 

 0.0566 

 0.0565 

 0.0563 

 0.0560 

 0.0557 

 0.0555 

 0.0554 

 0.0553 

 0.0550 



0.0552 

 0.0547 

 0.0544 

 . 0603 

 . 0592 

 0.0586 

 0.0627 



0.0594 

 0.0578 



0.0630 



4 77 

 4 80 

 5 . 09 



159 

 127 

 097 

 075 

 030 

 975 

 921 

 869 

 847 

 822 

 776 



Relative 

 intensity 



80 



15 



100 



15 



5 

 10 



5 

 80 

 15 

 60 

 10 



6 



4 



1 

 10 



1 

 1 



100 

 19 



Thorium Series 



Thorium 

 Mesothorium 1 

 Mesothorium 2 

 Radiothorium 



Thorium X 

 Thoron 

 Thorium A 

 Thorium B 

 Thorium C 



1.389 X 10'° y 

 6.7 y 

 6.13 h 

 1.90 y 



3.64 d 

 54.50 s 

 0. 145 s 



10 6 h 

 60.6 m 



2.80 



(3.67) 



4.08 



5.004 



5.638 



.20 

 0- 

 0- 

 .420 

 .335 

 6825 

 2818 

 7744 



/s- 



083 



27.2 



