Authors: Balraj Singh and Jun Chen |  Citation: Nucl. Data Sheets 147, 1 (2018) |  Cutoff date: 30-Nov-2017 

 Full ENSDF file | Adopted Levels (PDF version) 

Q(β-)=6390 keV 50S(n)= 4970 keV SYS(p)= 9950 keV SYQ(α)= -2800 keV SY
Reference: 2017WA10

General Comments:

2008Os02: 164Eu identified in U(p,X) at E(p)=24 MeV on target of natural uranium in the form of uranium carbide. The fission fragments mass separated as metallic ions and implanted on to a tape transport system. Measured β, βγ coin, γγ coin, T1/2. The 164Eu isotope was identified by observing K-x rays of Gd, and five γ rays from its decay, including the 73.3 and 168.8 keV γ rays, which are close in energy to those observed by 2004Jo17 and assigned as 2+ to 0+ and 4+ to 2+ transitions in 164Gd, respectively.

2007Ha57 (same group as 2008Os02): source prepared by 238U(p,F) at E(p)=32 MeV at JAEA facility. Fission products were ionized and separated online using Tokai-ISOL mass separator. Measured Q(β-) using total absorption gamma-ray spectrometer of BGO detector. Deduced mass excess=-53320 410 (2007Ha57), value includes systematic predictions in mass evaluations.

2014Ha38, 2010Ha38: measured Q(β-) using total absorption spectrometer of clover Ge detector and 4π BGO detectors serving as Compton suppressors at JAEA facility. Measured Q(β-)=6393 keV 50

2017Wu04: 164Eu nuclide was produced at the RIBF-RIKEN facility using the 9Be(238U,F) reaction at E=345 MeV/nucleon. Two experiments, optimized for the transmission of 158Nd and 170Dy ions, were carried out with average beam intensities of 7 pnA and 12 pnA, respectively. The identification of the nuclide of interest was made in the BigRIPS separator by determining the atomic number and the mass-to-charge ratio of the ion using the tof-Bρ-ΔE method. The reaction products were transported through the ZeroDegree spectrometer and implanted into the beta-counting system WAS3ABi that was surrounded by the EURICA array comprising of 84 HPGe detectors. The typical implantation rate was ≈100 ions/s. Measured (implanted ions)(β-)t, (implanted ions)(β-)γ-t, (implanted ions)γ-t correlations, and half-life of the decay of 164Eu.

2017Pa25: 164Eu isomer populated in 9Be(238U,F), E=345 MeV/nucleon reaction at RIBF, RIKEN facility using the BigRIPS and ZeroDegree spectrometers for separation and identification of in-flight fission fragments. Delayed gamma rays were detected using EURICA (Euroball-RIKEN Cluster) array, consisting of 84 HPGe crystal. Measured Eγ, delayed γ spectra. Deduced evidence for a micro-second isomer in 164Eu from the observation of delayed γ rays of 53.7, 89.5, 120.4 and 214 keV from the excited states of 164Eu, but neither an exact half-life nor the decay scheme could be obtained.

Q-value: Estimated uncertainties (syst,2017Wa10): ΔS(n)=130, ΔS(p)=320, ΔQ(α)=230

Q-value: S(2n)=10820 120, S(2p)=21590 320, Q(β-n)=-140 110 (syst,2017Wa10)

Jπ(level) T1/2(level)
    0 (3) 4.15 s 20 
% β- = 100

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Additional Level Data and Comments:

  0+X   Following γ rays depopulate the isomer according to γ-spectrum shown in Fig. 16 of 2017Pa25: 53.7, 89.5, 120.4 and 214 keV.

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