Author: Balraj Singh |  Citation: Nucl. Data Sheets 156, 70 (2019) |  Cutoff date: 31-Jan-2019 

 Full ENSDF file | Adopted Levels (PDF version) 

Q(β-)=-5600 keV SYS(n)= 7520 keV SYS(p)= 3650 keV SYQ(α)= 9070 keV 40
Reference: 2017WA10

General Comments:

2006Dv01, 2008Dv02: 270Hs produced and first identified in 248Cm(26Mg,4n),E=193,185 MeV reaction at GSI, and assignment to the isotope made through the observation of four correlated (α-SF) decay chains in 2006Dv01, and two in 2008Dv02 which were attributed to 270Hs on the basis of α particle decay to 266Sg, which decays by SF mode. Rapid chemical separation and on-line detection method used for isolation of Hs. Detection system was a linear array of Passivated Implanted Planar Silicon (PIPS) detectors. In this experiment eight other correlated chains were assigned to 269Hs, one tentatively to 271Hs, and two were unassigned, one of which could possibly belong to 270Hs.

The following α-SF correlated decay chains were assigned to 270Hs (2006Dv01):

Event #1: E(26Mg)=145 MeV

Eα=8.85 MeV, assigned to 270Hs

ESF=100 and 74 MeV, Δt2=1.62 s, assigned to 266Sg

Event #2: E(26Mg)=136 MeV

Eα=8.90 MeV, assigned to 270Hs

ESF=89 and 55 MeV, Δt2=49.6 ms, assigned to 266Sg

Event #3: E(26Mg)=136 MeV

Eα=8.92 MeV, assigned to 270Hs

ESF=106 and 82 MeV, Δt2=449 ms, assigned to 266Sg

Event #4: E(26Mg)=136 MeV

Eα=8.88 MeV, assigned to 270Hs

ESF=96 and 110 MeV, Δt2=444 ms, assigned to 266Sg

The following α-SF correlated decay chains were assigned to 270Hs (2008Dv02):

Event #1: E(26Mg)=140 MeV

Eα=8.76 MeV 20, assigned to 270Hs

ESF=58 and 61 MeV, Δt2=275 ms, assigned to 266Sg

Event #2: E(26Mg)=140 MeV

Eα=8.81 MeV 16, assigned to 270Hs

ESF=92 and 111 MeV, Δt2=271 ms, assigned to 266Sg

2010Gr04: 270Hs produced in 238U(36S,4n),E=175-197 MeV in mid-target corresponding to excitation energy of E*=39 MeV 4, close to the predicted maxima of the 4n- and 5n-evaporation channels. Experiments carried out using UNILAC and highly efficient chemical separation and detection system COMPACT connected to a recoil chamber at GSI. One decay chain 270Hs |) 266Sg was assigned to 270Hs with a production σ=0.8 pb +26-7, half-life of 270Hs=23 s, and Eα=8.88 MeV. See also 2012Tu01.

2013Og03: 270Hs isotope produced in 226Ra(48Ca,4n) reaction.

E(48Ca)=229, 234, 241 MeV provided by the U400 cyclotron of the FLNR-JINR facility. Targets=0.12 and 0.18 mg/cm2 226Ra. Separation of evaporation residues (EVR) and beam particles using Dubna gas-filled recoil separator (DGFRS). Measured Eα, Iα, fission fragments, EVR-α and EVR-SF correlated events, time-of-flight, T1/2, production σ. Particle and α detected by an array of semiconductor detectors.

History of six correlated decay chains of EVR-α-SF type (2013Og03):

Event #1: E(EVR)=11.537 MeV

Eα=8.923 MeV, Δtα=1.8537 s, assigned to 270Hs

ESF=165.2 MeV, ΔtSF=0.9196 s, assigned to 266Sg

Event #2: E(EVR)=11.356 MeV

Eα=9.133 MeV, Δtα=31.9395 s, assigned to 270Hs

ESF=148.7 MeV, ΔtSF=0.7517 s, assigned to 266Sg

Event #3: E(EVR)=11.461 MeV

Eα=9.024 MeV, Δtα=9.7087 s, assigned to 270Hs

ESF=>187.9 MeV, ΔtSF=0.0708 s, assigned to 266Sg

Event #4: E(EVR)=13.864 MeV

Eα=8.991 MeV, Δtα=7.3538 s, assigned to 270Hs

ESF=196.3 MeV, ΔtSF=0.3081 s, assigned to 266Sg

Event #5: E(EVR)=13.812 MeV

Eα=9.009 MeV, Δtα=8.1642 s, assigned to 270Hs

ESF=168.6 MeV, ΔtSF=0.2450 s, assigned to 266Sg

Event #6: E(EVR)=15.993 MeV

Eα=8.940 MeV, Δtα=6.4194 s, assigned to 270Hs

ESF=193.9 MeV, ΔtSF=0.1629 s, assigned to 266Sg

Earlier studies where production of 270Hs was claimed in experiments at GSI, but later reassigned to 269Hs in further experiments at GSI (2006Dv01, 2008Dv02), later confirmed by 2013Og03 in experiments at Dubna:

2002Du21, 2003Tu05, 2003Du27 (also 2003Kr24 review): production of 270Hs reported in 248Cm(26Mg,4n),E=143.7-146.8 MeV followed by chemical procedures employing gas chromatography undertaken at GSI using the UNILAC facility. Two correlated decay chains were tentatively assigned to 270Hs, with a production cross-section of 4 pb for 270Hs. Measured Eα=9.16 MeV +7-3, and α-decay half-life=3.6 s +8-14 for the decay of 270Hs. In later experiments by 2006Dv01, the two chains reported by 2003Tu05 were reassigned to 269Hs, instead.

2004Ga18: measured yield.

2004Vo24: this experiment reports mainly the chemistry of Z=108 (Hs) element through the formation of 269Hs or 270Hs in 248Cm(26Mg,4n) at GSI. Three α-α-SF correlated events were assigned to the decay of 269Hs or 270Hs.

For theoretical studies, consult Nuclear Science References (NSR) database at NNDC, BNL for 122 primary references dealing with the half-lives and other aspects of nuclear structure in this mass region

Q-value: Estimated uncertainties (2017Wa10): ΔQ(β-)=300, ΔS(n)=280, ΔS(p)=450

Q-value: S(2n)=13860 380, S(2p)=6270 530 (syst, 2017Wa10)

Jπ(level) T1/2(level)
  0 0+ 7.6 s +49-22 
% α > 50
% SF < 50

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Additional Level Data and Comments:

  00+ 7.6 s +49-22 
% α > 50
% SF < 50
Measured Eα=9020 80 (2013Og03) from α decay of 270Hs. Other: 8.93 MeV 10 (2012Tu01).

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