ADOPTED LEVELS, GAMMAS for 251Bk

Author: C. Morse |  Citation: Nucl. Data Sheets 189, 111 (2023) |  Cutoff date: 23-Sep-2022 

 Full ENSDF file | Adopted Levels (PDF version) 


Q(β-)=1093 keV 10S(n)= 5795 keV 11S(p)= 5051 keV 15Q(α)= 5650 keV SY
Reference: 2021Wa16

References:
  A  251Cm β- decay  B  255Es α decay







E(level)
(keV)		XREFJπ(level) T1/2(level)E(γ)
(keV)		I(γ)Final Levels
    0AB (3/2-) 56 m 1 
% β- = 100
    
   32.5 6 AB (5/2-)      32.6
  100
    0
(3/2-)
   35.5 14 AB (7/2+) 40 µs 3      
   72 B (9/2+)       
  123 B (11/2+)       
  269.1 10 AB (5/2+)     233.6
  269.1
  100
 
   35.5
    0
(7/2+)
(3/2-)
  311.7 10 A  (1/2+)     311.7
  100
    0
(3/2-)
  422.3 8 A  (3/2-)     389.7
  422.3
  100 15 
   56 7 
   32.5
    0
(5/2-)
(3/2-)
  438.2 10 A  (1/2-)     438.2
  100
    0
(3/2-)
  542.6 8 A  (1/2-)     542.7
  100
    0
(3/2-)
  562.5 7 A  (3/2-)     530.0
  562.5
  100 7 
   63 20 
   32.5
    0
(5/2-)
(3/2-)
  978.4 6 A  (1/2-,3/2-)     415.9
  435.8
  945.9
  978.2
   16 7 
   15 5 
   15 8 
  100 13 
  562.5
  542.6
   32.5
    0
(3/2-)
(1/2-)
(5/2-)
(3/2-)

E(level): From least-squares fit to Eγ, with uncertainties assumed to be 1 keV from 251Cm β- decay. For levels only observed in 255Es α decay, energies are from Eα.

Jπ(level): From 251Cm β- decay (1978Lo13), unless only observed in 255Es α decay.

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Band Transitions:

E(level)
(keV)		Jπ(level) T1/2(level)E(γ)I(γ)Final Levels
Band 1 - π3/2-[521].
    0 (3/2-) 56 m 1 
% β- = 100
    
   32.5 6  (5/2-)      32.6
  100
    0
(3/2-)
E(level)
(keV)		Jπ(level) T1/2(level)E(γ)I(γ)Final Levels
Band 2 - π7/2+[633].
   35.5 14  (7/2+) 40 µs 3      
   72 (9/2+)     
  123 (11/2+)       
E(level)
(keV)		Jπ(level) T1/2(level)E(γ)I(γ)Final Levels
Band 3 - π1/2-[530].
  422.3 8  (3/2-)       
  438.2 10  (1/2-)     438.2
  100
    0
(3/2-)
E(level)
(keV)		Jπ(level) T1/2(level)E(γ)I(γ)Final Levels
Band 4 - π1/2-[521].
  542.6 8  (1/2-)       
  562.5 7  (3/2-)     530.0
  562.5
  100 7 
   63 20 
   32.5
    0
(5/2-)
(3/2-)

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Additional Level Data and Comments:

E(level)Jπ(level)T1/2(level)Comments
    0(3/2-) 56 m 1 
% β- = 100
CONF=|p3/2-[521] (1978Lo13)
E(level): π3/2-[521].
   32.5(5/2-)   E(level): π3/2-[521].
   35.5(7/2+) 40 µs 3  CONF=|p7/2+[633] (1978Lo13)
E(level): π7/2+[633].
   72(9/2+)   E(level): π7/2+[633].
  123(11/2+)   E(level): π7/2+[633].
  422.3(3/2-)   CONF=|p1/2-[530] (1978Lo13)
Jπ(level): From 251Cm β decay, log ft values exclude J|>5/2. Aside from the 978.4 keV state, Jπ and configuration assignments are largely based on analogy with the level scheme observed in 249Cm β decay to 249Bk as discussed in 1978Lo13.
  438.2(1/2-)   Jπ(level): From 251Cm β decay, log ft values exclude J|>5/2. Aside from the 978.4 keV state, Jπ and configuration assignments are largely based on analogy with the level scheme observed in 249Cm β decay to 249Bk as discussed in 1978Lo13.
  542.6(1/2-)   CONF=|p1/2-[521] (1978Lo13)
Jπ(level): From 251Cm β decay, log ft values exclude J|>5/2. Aside from the 978.4 keV state, Jπ and configuration assignments are largely based on analogy with the level scheme observed in 249Cm β decay to 249Bk as discussed in 1978Lo13.
  562.5(3/2-)   Jπ(level): From 251Cm β decay, log ft values exclude J|>5/2. Aside from the 978.4 keV state, Jπ and configuration assignments are largely based on analogy with the level scheme observed in 249Cm β decay to 249Bk as discussed in 1978Lo13.
  978.4(1/2-,3/2-)   Jπ(level): From 251Cm β decay, log ft values exclude J|>5/2. Aside from the 978.4 keV state, Jπ and configuration assignments are largely based on analogy with the level scheme observed in 249Cm β decay to 249Bk as discussed in 1978Lo13.

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