Authors: Balraj Singh and Jun Chen |  Citation: Nucl. Data Sheets 185, 2 (2022) |  Cutoff date: 23-Aug-2022 

 Full ENSDF file | Adopted Levels (PDF version) 

Q(β-)=9530 keV SYS(n)= 4460 keV SYS(p)= 11940 keV SYQ(α)= -4590 keV SY
Reference: 2021WA16

General Comments:

1987Ra12: Yield of 149Cs is reported as 105 atoms/s in U(p,X) E=600 MeV reaction using ISOLDE On-Line Mass Separator

2000KoZH: ISOLDE On-Line Mass Separator. Measured Eγ, Iγ, En, In; deduced T1/2, nuclear magnetic moments, β-delayed neutron emission probabilities

2017Wu04: The 149Cs 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-, (implanted ions)β--γ and (implanted ions)γ correlations. Deduced half-life of the decay of 149Cs g.s.

2017Li06: 149Cs produced at ISOLDE-CERN facility through U(p,X) reaction with E(p)=1.4 GeV beam from the PS-Booster incident on UCx target. Measured yield, Eγ, Iγ, βγ-coin, half-life of ground state of 149Cs isotope from γ-decay curves using plastic scintillation detectors for β particles, LaBr3(Ce) and HPGe clover detectors for γ detection.

2018Sh11: 149Cs produced at the RIBF-RIKEN facility using 9Be(238U,F) reaction with 238U86+ beam of E=345 MeV/nucleon. Comparison of measured cross sections with theoretical calculations using LISE+ abrasion-fission (AF) model.

2020Wu04: 149Cs nuclide produced at the RIBF-RIKEN facility in 9Be(238U,F) reaction at E=345 MeV/nucleon and an intensity of 5 pnA. Identification of fission fragments of interest was made based ON time-of-flight (tof), magnetic rigidity (Bρ), and energy loss (ΔE) using the BigRIPS spectrometer, determining atomic Z and mass-to-charge ratio α/Q, where Q=charge state of the ions. The separated nuclei were implanted at a rate of 100 ions/s in the β counting system of the Wide range Active Silicon-Strip Stopper Array for Beta and ion detection (WAS3ABi), which included a stack of five Double Sided Silicon Strip Detectors (DSSSDs). The WAS3ABi setup was surrounded by Euroball RIken Cluster Array (EURICA) array of 84 HPGe detectors for γ detection. Half-life of the separated and implanted ions was determined by fitting the time distribution of β(implants)- and/or βγ(implants)-correlated decay curves to the sum of activities of parent nuclei, daughter nuclei, grand-daughter nuclei, β-delayed neutron daughter and grand-daughter nuclei, and a constant background. Comparison of measured half-lives with FRDM+QRPA (2003), FRDM+QRPA (2019), KTUY+GT2, RHB+pn-RQRPA, and DF+CQRPA theoretical calculations.

150Xe isotope has been identified by 2018Sh11 at RIKEN, but its decay characteristics through β- and β-n, populating 150Cs and 149Cs, respectively are unknown.

2018Ar04: theory: calculated binding energy, charge, proton, and neutron radii, S(n), S(2n), quadrupole deformation parameter, neutron skin thickness, and pairing gap energy using Skyrme Hartree-Fock Bogoliubov (HFB) approach.

Q-value: Estimated uncertainties (2021Wa16): ΔQ(β-)=400, ΔS(n)=400, ΔS(p)=500, ΔQ(α)=640

Q-value: S(2n)=7520 400, S(2p)=26680 500, Q(β-n)=6170 400 (syst, 2021Wa16).

  0 107 ms 6 
% β- = 100
% β-n = 25 4

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Additional Level Data and Comments:

  0 107 ms 6 
% β- = 100
% β-n = 25 4
-n deduced by 2017Li06 from the ratio of number of 148Ba 149Cs nuclei using absolute γ-ray intensities in 149Ba, 148La and 148Cs, the latter two from β-n decay modes.
E(level): %β-n deduced by 2017Li06 from the ratio of number of 148Ba 149Cs nuclei using absolute γ-ray intensities in 149Ba, 148La and 148Cs, the latter two from β-n decay modes.

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