ADOPTED LEVELS, GAMMAS for 157Ta

Author: N. Nica |  Citation: Nucl. Data Sheets 132, 1 (2016) |  Cutoff date: 4-Dec-2015 

 Full ENSDF file | Adopted Levels (PDF version) 


Q(β-)=-10123 keV 427S(n)= 11803 keV 334S(p)= -935 keV 10Q(α)= 6355 keV 6
S(2n)= 21808 keV 334S(2p)= 1.63×103 keV 10Q(EC)= 9310 keV 247Q(ECp)= 6.82×103 keV 14
Reference: 2017WA10

References:
  A  161Re α decay (14.7 MS)  B  157W ε decay
  C  102Pd(58Ni,p2nγ) 

General Comments:

This data set has been prepared, in part, from the evaluation of the proton radioactivity (2002So02) which populates 156Hf. This nuclide has been produced by 102Pd(58Ni,p2n) with E(58Ni) = 270 MeV in recoil mass separator with PPAC/DSSD detectors at focal plane (1997Ir01) and same reaction and measurements with E(58Ni) = 290 MeV (1996Pa01).

Theoretical works related to the nuclear shape and the separation or decay energies are:

2001Go20: β2=0.00, β4=0.00, S(p)=-0.5 MeV

1997Mo25: S(p)=-0.48 MeV, S(2p)=1.76 MeV, Q(α)=6.20 MeV, T1/2(β)=0.5664 s, T1/2(α)=2.570 ms

1995Mo29: β2=0.045, β4=0.001, β6=0.000

1995Ab38: β2=0.12, β4=0.01, S(p)=-0.8 MeV

1976Li30: S(p)=-0.79 MeV, Q(α)=5.97 MeV










E(level)
(keV)		XREFJπ(level) T1/2(level)E(γ)
(keV)		I(γ)M(γ)Final Levels
     0.0  C 1/2+ 10.1 ms 4 
% p = 3.4 12
% α = 96.6 12
     
    22 5 A C 11/2- 4.3 ms 1 
% α = 100
     
   864.0 3   C 15/2(-)     842.0
  100
Q
    22
11/2-
  1567.2 5   C 19/2(-)     703.2
  100
Q
   864.0
15/2(-)
  1589 10 ?    (25/2-) 1.7 ms 1 
% α = 100
     
  1717.8 6   C (23/2-) ≈ 5 ns   150.6
  100
Q
  1567.2
19/2(-)
  2360.4 6   C (27/2-)     642.6
  100

  1717.8
(23/2-)
  2927.7 7   C (29/2+)     567.3
  100

  2360.4
(27/2-)
  3065.4 8   C (31/2+)     137.7
  100
(D)
  2927.7
(29/2+)
  3353.9 8   C     288.5
  100

  3065.4
(31/2+)
  3678.1 9   C     324.2
  100

  3353.9

  3986.9 9   C     633.0
  100

  3353.9

E(level): From least-squares fit to Eγ’s (for levels higher than 22 keV); ΔEγ=0.3 keV

M(γ): From angular distribution measurements (102Pd(58Ni,p2nγ), 2005Se11)

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Band Transitions:

E(level)
(keV)		Jπ(level) T1/2(level)E(γ)I(γ)M(γ)Final Levels
Band 1 - πh11/2~#(νf7/2)2
    22 5  11/2- 4.3 ms 1 
% α = 100
     
   864.0 3  15/2(-)        
  1567.2 5  19/2(-)     703.2
  100
Q
   864.0
15/2(-)
E(level)
(keV)		Jπ(level) T1/2(level)E(γ)I(γ)M(γ)Final Levels
Band 2 - πh11/2~#νf7/2h9/2 multiplet
  1717.8 6  (23/2-) ≈ 5 ns      
  2360.4 6  (27/2-)        
E(level)
(keV)		Jπ(level) T1/2(level)E(γ)I(γ)M(γ)Final Levels
Band 3 - πh11/2~#[(νf7/2)2~#3-+νf7/2i13/2]
  2927.7 7  (29/2+)        
  3065.4 8  (31/2+)        
  3353.9 8      288.5
  100

  3065.4
(31/2+)
  3986.9 9      633.0
  100

  3353.9

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Additional Level Data and Comments:

E(level)Jπ(level)T1/2(level)Comments
     0.01/2+ 10.1 ms 4 
% p = 3.4 12
% α = 96.6 12
1996Pa01 observe a single proton radioactivity event with E(p)=919 keV 17, 11 ms after implantation of 157Ta nuclei.
E(level): 1996Pa01 observe a single proton radioactivity event with E(p)=919 keV 17, 11 ms after implantation of 157Ta nuclei.
    2211/2- 4.3 ms 1 
% α = 100
E(level): πh11/2~#(νf7/2)2.
   864.015/2(-)   E(level): πh11/2~#(νf7/2)2.
  1567.219/2(-)   E(level): πh11/2~#(νf7/2)2.
  1717.8(23/2-) ≈ 5 ns E(level): πh11/2~#νf7/2h9/2 multiplet.
  2360.4(27/2-)   E(level): πh11/2~#νf7/2h9/2 multiplet.
  2927.7(29/2+)   E(level): πh11/2~#[(νf7/2)2~#3-+νf7/2i13/2].
  3065.4(31/2+)   E(level): πh11/2~#[(νf7/2)2~#3-+νf7/2i13/2].
  3353.9   E(level): πh11/2~#[(νf7/2)2~#3-+νf7/2i13/2].
  3986.9   E(level): πh11/2~#[(νf7/2)2~#3-+νf7/2i13/2].

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Additional Gamma Comments:

E(level)E(gamma)Comments
   864.0   842.0M(γ): stretched ΔJ=2 based on angular distribution ratio
  1567.2   703.2M(γ): stretched ΔJ=2 based on angular distribution ratio
  1717.8   150.6M(γ): E2 multipolarity favoured for this transition, based upon single-particle Weiskopff estimates. Assignment further supported by intensity balance arguments
  3065.4   137.7M(γ): likely to be M1 from angular distribution ratio.

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