ADOPTED LEVELS for 225Po

Authors: Balraj Singh and Michael Birch |  Citation: ENSDF |  Cutoff date: 15-MAY-2011 

 Full ENSDF file | Adopted Levels (PDF version) 


Q(β-)=4.1×103 keV SYS(n)= 3.5×103 keV SYS(p)= 9.5×103 keV SY
Reference: 2012WA38

General Comments:

2010Al24: 225Po nuclide identified in 9Be(238U,X) reaction with a beam energy of 1 GeV/nucleon produced by the SIS synchrotron at GSI facility. Target=2500 mg/cm2. The fragment residues were analyzed with the high resolving power magnetic spectrometer Fragment separator (FRS). The identification of nuclei was made on the basis of magnetic rigidity, velocity, time-of-flight, energy loss and atomic number of the fragments using two plastic scintillators and two multisampling ionization chambers. The FRS magnet was tuned to center on 210Au, 216Pb, 219Pb, 227At and 229At nuclei along the central trajectory of FRS.

Unambiguous identification of nuclides required the separation of different charge states of the nuclei passing through the FRS. At 1 GeV/nucleon incident energy of 238U, fraction of fully stripped 226Po nuclei was about 89%. Through the measurement of difference in magnetic rigidity in the two sections of the FRS and the difference in energy loss in the two ionization chambers, the charge state of the transmitted nuclei was determined, especially, that of the singly charged (hydrogen-like) nuclei which preserved their charge in the current experimental setup. Measured production cross sections with 10% statistical and 20% systematic uncertainties

Criterion established in 2010Al24 for acceptance of identification of a new nuclide: 1. number of events should be compatible with the corresponding mass and atomic number located in the expected range of positions at both image planes of the FRS spectrometer; 2. number of events should be compatible with >95% probability that at least one of the counts does not correspond to a charge-state contaminant. Comparisons of measured σ with model predictions using the computer codes COFRA and EPAX.

Q-value: Note: Current evaluation has used the following Q record

Q-value: Estimated uncertainties in 2011AuZZ: 500 for Q(β-) and S(p), 420 for S(n)

Q-value: Q(β-), S(n), and S(p) from 2011AuZZ, Q(α) from 1997Mo25

Q-value: S(2n)=8690 360 (syst,2011AuZZ), S(2p)=18450 (1997Mo25,calculated)




E(level)
(keV)
T1/2(level)
  0 > 300 ns
% β- = ?

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Additional Level Data and Comments:

E(level)Jπ(level)T1/2(level)Comments
  0 > 300 ns
% β- = ?
Production cross section measured in 2010Al24, values are given in figure 2, plot of σ versus mass number for Po isotopes. Statistical uncertainty=10%, systematic uncertainty=20%.

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