ADOPTED LEVELS, GAMMAS for 217Th

Authors: B. Singh, R. Shearman |  Citation: Nucl. Data Sheets 147, 382 (2018) |  Cutoff date: 1-DEC-2017 

 Full ENSDF file | Adopted Levels (PDF version) 


Q(β-)=-4863 keV 19S(n)= 6164 keV 16S(p)= 3228 keV 15Q(α)= 9435 keV 4
Reference: 2017WA10

References:
  A  217Th IT decay (141 NS)  B  217Th IT decay (67 μs)
  C  221U α decay (0.66 μs) 

General Comments:

217Th evaluated by B. Singh and R. Shearman

1968Va18: 217Th produced and identified in 206Pb(16O,5n),E=166 MeV at Berkeley HILAC facility, He-jet system, measured half-life of 217Th decay. Later studies for production and decay of 217Th isotope: 204Pb(16O,3n),E=91 MeV at Chalk-River (1973Ha32); 198Pt(28Si,α5n),E=140-180 MeV at JAERI-tandem accelerator (2000Ni02); 170Er(51V,p3n),E=214-286 MeV and 170Er(50Ti,3n),E=215-235 MeV at GSI (2000He17); 181Ta(40Ar,p3n),E=182 MeV at GSI (2002He29); 170Er(50Ti,3n),E=4.35 MeV/nucleon at GSI (2005Ku31); 176Yb(50Ti,α5n),E(50Ti)=231-255 MeV at GSI (2015Kh09).

2007Ma57 claimed to have found evidence for very long-lived isomers in 211,213,217,218Th in naturally-occurring Th sample using inductively coupled plasma-sector field mass spectrometry, and suggested that such isomers could be associated with a new class of long-lived high-spin superdeformed or hyperdeformed structures. However, 2008La14, using accelerator mass spectrometry (AMS), with two orders of magnitude higher sensitivity than in 2007Ma57, could not confirm the existence of such long-lived activities.

Q-value: S(2n)=14858 14, S(2p)=4906 13, Q(εp)=1626 14 (2017Wa10)










E(level)
(keV)		XREFJπ(level) T1/2(level)E(γ)
(keV)		I(γ)M(γ)Final Levels
     0.0ABC (9/2+) 0.252 ms 4 
% α = 100
     
   673.3 1 AB  (15/2-) 141 ns 50 
% IT = 100
   673.3 1 
  100
(E3)
     0.0
(9/2+)
  1942.61 15  B  (17/2+)     1269.3 1 
  100
[E1]
   673.3
(15/2-)
  2251.91 18  B  (21/2+)      309.3 1 
  100
[E2]
  1942.61
(17/2+)
  2251.91+X B  (25/2+) 67 µs +17-11 
% IT = 100
     X
 

  2251.91
(21/2+)

E(level): Deduced by evaluators from Eγ data

Jπ(level): From similarity to level structures and isomers in n=127 isotones 215Ra, 213Rn, 211Po and 209Pb (1989Dr02)

E(γ): From 217Th IT decay (67 μs)

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Additional Gamma Data:













E(level)
(keV)		Jπ(level)T1/2(level)E(γ)
(keV)		MultipolarityConversion
Coefficient		Additional Data
   673.3 (15/2-) 141 ns 50 
% IT = 100
   673.3 1 (E3)0.0654B(E3)(W.u.)=46 +25-12, α=0.0654, α(K)=0.0367 6, α(L)=0.0211 3, α(M)=0.00561 8, α(N)=0.001507 22, α(O)=0.000346 5, α(P)=6.18E-5 9, α(Q)=2.67E-6 4
  1942.61 (17/2+)     1269.3 1 [E1]0.01784α=0.01784, α(K)=0.01437 21, α(L)=0.00261 4, α(M)=0.000624 9, α(N)=0.0001663 24, α(O)=3.94×10-5 6, α(P)=7.66E-6 11, α(Q)=7.34E-7 11
  2251.91 (21/2+)      309.3 1 [E2]0.1538α=0.1538, α(K)=0.0686 10, α(L)=0.0627 9, α(M)=0.01679 24, α(N)=0.00450 7, α(O)=0.001016 15, α(P)=0.0001754 25, α(Q)=4.24×10-6 6

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Additional Level Data and Comments:

E(level)Jπ(level)T1/2(level)Comments
     0.0(9/2+) 0.252 ms 4 
% α = 100
The main α transition observed at Eα=9269 9 (2005Ku31), 9261 5 (2002He29), 9268 10 (2000He17), 9247 15 (2000Ni02), 9250 20 (1973Ha32), 9250 10 (1968Va18). Non-observation of (9269α)γ-coin (2005Ku31) is consistent with 9269α being a ground-state to ground-state transition.

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Additional Gamma Comments:

E(level)E(gamma)Comments
   673.3   673.3M(γ): from ce measurements in 1989Dr02 (see 217Th IT decay (141 ns) dataset); also systematics of n=127 isotones
  2251.91+X     XE(γ): x<110 keV, from small number of thorium K x-rays observed in γγ-coincidences gated by the 309, 673 or 1269 keV γ-rays 2005Ku31 concluded that the transition energy is probably below the K-electron binding energy of ≈110 keV
M(γ): E2 expected from systematics of n=127 isotones

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