Author: Balraj Singh |  Citation: ENSDF |  Cutoff date: 18-DEC-2015 

Authors: Ashok Jain, Sukhjeet Singh, Suresh Kumar, Jagdish Tuli |  Citation: Nucl. Data Sheets 108, 883 (2007) |  Cutoff date: 15-Jan-2007 

 Full ENSDF file | Adopted Levels (PDF version) 

Q(β-)=-5360 keV SYS(n)= 6520 keV SYS(p)= 3020 keV SYQ(α)= 9840 keV SY
Reference: 2012WA38

General Comments:

2015Kh09: 221U produced in 176Yb(50Ti,5n),E(50Ti12+= 231-255 MeV reaction. The 50Ti12+ pulsed beam produced by the UNILAC at GSI. Target=0.45 mg/cm2 5 thick 176YbF3 mounted on a rotating wheel, synchronized with the beam pulses. Evaporation residues (Er), separated by using gas-filled TransActinide Separator and Chemistry Apparatus (TASCA) with flight time of 0.53 μs 6 through the separator, were implanted in a double-sided silicon strip detector. The events due to radioactive decays of implanted residues were selected from the events related to beam using a multiwire proportional counter (MWPC). Measured Eα, Iα, Er-α correlated events from subsequent α-decay chains, half-lives of parent nuclei corresponding to the evaporation residues, and successive α-decay daughters, the latter identified by their known characteristics in literature. The identification of 221U was made based on observed Er-α, two- or three-signal correlated events using a fast data acquisition and combined analog and digital (CANDI) readout system. α total of 26 Er traces were recorded for 221U and analyzed with subsequent α decay chain: 221U -> 217Th -> 213Ra. FWHM≈40 keV for 8.7 MeV α particles, recorded as single events, ≈110 keV and ≈180 keV for multiple α events stored in a single trace with time differences of 1 μs and 0.17 μs, respectively. Deduced α-decay reduced widths

Other: 2001Ni06: tentative formation in the 221U+217Th channel in Ce(82Se,X),E(c.m.)=215-253 MeV reaction, with evaporation residue cross-section of 17 to 21.6 nb at energies of 215 to 238 MeV

Theoretical structure calculations: 2013To12, 2010To07, 2008Ad04

Q-value: Estimated uncertainties (2012Wa38): 220 for Q(β-), 140 for S(n), 120 for S(p), 100 for Q(α)

Q-value: S(2n)=14950 110, S(2p)=4570 110, Q(εp)=2530 110 (2012Wa38); all values from systematic trend

Jπ(level) T1/2(level)
  0 (9/2+) 0.66 µs 14 
% α ≈ 100

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Additional Level Data and Comments:

  0(9/2+) 0.66 µs 14 
% α ≈ 100
Measured Eα=9.71 MeV 5 from the decay of 221U to 217Th (2015Kh09).

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