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

E_α=8.85 MeV, assigned to ²⁷⁰Hs

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

Event #2: E(²⁶Mg)=136 MeV

E_α=8.90 MeV, assigned to ²⁷⁰Hs

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

Event #3: E(²⁶Mg)=136 MeV

E_α=8.92 MeV, assigned to ²⁷⁰Hs

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

Event #4: E(²⁶Mg)=136 MeV

E_α=8.88 MeV, assigned to ²⁷⁰Hs

E_SF=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

E_α=8.76 MeV 20, assigned to ²⁷⁰Hs

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

Event #2: E(²⁶Mg)=140 MeV

E_α=8.81 MeV 16, assigned to ²⁷⁰Hs

E_SF=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/cm^{2 226}Ra. 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, T_1/2, 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

E_α=8.923 MeV, Δt_α=1.8537 s, assigned to ²⁷⁰Hs

E_SF=165.2 MeV, Δt_SF=0.9196 s, assigned to ²⁶⁶Sg

Event #2: E(EVR)=11.356 MeV

E_α=9.133 MeV, Δt_α=31.9395 s, assigned to ²⁷⁰Hs

E_SF=148.7 MeV, Δt_SF=0.7517 s, assigned to ²⁶⁶Sg

Event #3: E(EVR)=11.461 MeV

E_α=9.024 MeV, Δt_α=9.7087 s, assigned to ²⁷⁰Hs

E_SF=>187.9 MeV, Δt_SF=0.0708 s, assigned to ²⁶⁶Sg

Event #4: E(EVR)=13.864 MeV

E_α=8.991 MeV, Δt_α=7.3538 s, assigned to ²⁷⁰Hs

E_SF=196.3 MeV, Δt_SF=0.3081 s, assigned to ²⁶⁶Sg

Event #5: E(EVR)=13.812 MeV

E_α=9.009 MeV, Δt_α=8.1642 s, assigned to ²⁷⁰Hs

E_SF=168.6 MeV, Δt_SF=0.2450 s, assigned to ²⁶⁶Sg

Event #6: E(EVR)=15.993 MeV

E_α=8.940 MeV, Δt_α=6.4194 s, assigned to ²⁷⁰Hs

E_SF=193.9 MeV, Δt_SF=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)