ADOPTED LEVELS, GAMMAS for 208Ra

Author: M. J. Martin |  Citation: Nucl. Data Sheets 108,1583 (2007) |  Cutoff date: 1-Jun-2007 

 Full ENSDF file | Adopted Levels (PDF version) 


Q(β-)=-9.04×103 keV 6S(n)= 9.90×103 keV 6S(p)= 2730 keV 24Q(α)= 7273 keV 5
Reference: 2012WA38

References:
  A  208Ra IT decay  B  212Th α decay

General Comments:

All data for the excited levels are from 172Yb(40Ar,4nγ)

Q-value: Note: Current evaluation has used the following Q record -9046 589895 58 2737 53 7273 5 2003Au03










E(level)
(keV)		XREFJπ(level) T1/2(level)E(γ)
(keV)		I(γ)M(γ)Final Levels
     0.0AB 0+ 1.3 s 2 
% ε = 5 SY
% α = 95 SY
     
   520.2 2 A  (2+)     520.2 2 
 
[E2]
     0.0
0+
  1093.6 3 A  (4+)     573.4 2 
 
[E2]
   520.2
(2+)
  1468.4 3 A  (4+)     948.1 2 
 
[E2]
   520.2
(2+)
  1755.4 3 A  (6+)     661.9 2 
 
[E2]
  1093.6
(4+)
  2017.0 3 A  (6+)     261.5 2 
  548.6 2 
   50 7 
  100
[E2]
[E2]
  1755.4
  1468.4
(6+)
(4+)
  2147.4 4 A  (8+) 270 ns 21    130.2 2 
  392.1 2 
   33 5 
  100
[E2]
[E2]
  2017.0
  1755.4
(6+)
(6+)

Jπ(level): From systematics of even-even nuclei and analogy with 212,214Ra

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Additional Gamma Data:













E(level)
(keV)		Jπ(level)T1/2(level)E(γ)
(keV)		MultipolarityConversion
Coefficient		Additional Data
   520.2 (2+)     520.2 2 [E2]0.0356α=0.0356
  1093.6 (4+)     573.4 2 [E2]0.0284α=0.0284
  1468.4 (4+)     948.1 2 [E2]0.0101α=0.0101
  1755.4 (6+)     661.9 2 [E2]0.0208α=0.0208
  2017.0 (6+)     261.5 2 [E2]0.237α=0.237
(6+)     548.6 2 [E2]0.0314α=0.0314
  2147.4 (8+) 270 ns 21    130.2 2 [E2]3.19B(E2)(W.u.)=0.102 12, α=3.19
(8+) 270 ns 21    392.1 2 [E2]0.0723B(E2)(W.u.)=0.00222 21, α=0.0723

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Additional Level Data and Comments:

E(level)Jπ(level)T1/2(level)Comments
     0.00+ 1.3 s 2 
% ε = 5 SY
% α = 95 SY
%ε based on (ε+β+) strength function estimate (1973Ta30) note that, based on log ft>5.9, I(ε+β+)<0.5% to any single level in 208Fr with E<1 MeV.
E(level): %ε based on (ε+β+) strength function estimate (1973Ta30) note that, based on log ft>5.9, I(ε+β+)<0.5% to any single level in 208Fr with E<1 MeV.

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Additional Gamma Comments:

E(level)E(gamma)Comments
  2017.0   261.5M(γ): the intensity imbalance at the 2017 level [I(γ+ce)(in)=65, I(γ+ce)(out)=40], suggests that the (6+) to (6+) 261.5γ may have an E0 component. One gets α(261γ)=2.3 7 compared with α(E2)=0.237 and α(M1)=1.09

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