New²³³U levels fed in the²³³Pa β-decay

Abstract

The 6-decay of radiochemically separated 233Pa sources has been reinvestigated using planar and coaxial HPGe detectors: the energies and intensities of 23 y-photons were determined in this work, eight of them are reported for the first time; the placement of the main y-lines was confirmed by y-y coincidence measurements.A 233U revised level scheme exhibits eleven excited states, of which three are newly proposed at energies 320.90, 380.30 and 455.96 keV, respectively interpreted as the I" = 5/2-member of the 5/2-[752] rotational band, the In = 7/2+ member of the 3/2+[631] band and the 5/2' member of the 1/2+ [631] band. The I n = 5 / 2 -level at 301.99 keV, observed in Coulomb excitation experiments, is also fed in 233Pa P-decay. RADIOACTIVITY 233Pa; measured E,, I,, ZK-x, y-y coinc.; deduced Is, logft; deduced 233U levels E, K, I, ~d, Nilsson assignments; Coriolis matrix elements; coaxial and planar HPGe detectors.

Fast Radiochemical Separation and γ Spectroscopy of Short-lived Thallium Isotopes

“…The (3389.06 + 0.20) keV level is supported by the existence of a coincidence relationship of the y-line of 1239.8 keV with the energy gate of 117 keV [1]. This level may be identical to the 3389 keV level observed in the (d,p) reaction [13].…”

“…Energies and intensities of the y-rays following the β~ decay of 209 T1 Intensities are normalized to 100 β~ decays of 209 T1; uncertainties (1 SD) on the values, in parentheses, are given on last digits of the figure, a) y-transition also reported in Ref. [1]. b) Intensity normalized to 100 α decays of 229 Th.…”

“…A level at (3069.64 + 0.08) keV is proposed to interpret the coincidence of the 920.34 keV y-transition with the gates of 117 and 465 keV [1]. This level seems identical to the (3076 + 5) keV state observed in the Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 7/4/15 9:04 AM 208 Pb(d,p) [13] and 207 Pb(t,p) [16] reactions; a configuration v(2g 9/2 )j = 0 + ® v(3p 3/2 )~1 was proposed.…”

“…Lederer and Shirley [11] 213 Bi equilibrium source [1] and the Ritz combination principle involving nuclear levels observed in different nuclear reactions such as 208 Pd(d,p) [13], 208 Pd(d,py) [14], 208 Pb(t,d) [15], 207 Pb(t,p) [16], and 208 Pb(a, 3 He) [17], The intensity balance for each level was calculated correcting y transitions intensities for internal conversion and assuming, as consequence of the selection rules, that neither the 209 Pb ground state (P = 9/2 + ) nor the two first excited states at 779 keV (F = 11/2 + ) and 1596.96 keV (F = 5/2 + ) have /Γ-feeding. For the main cascade deexciting the I" = 1/2" level at 2149.30 keV, we corrected the 117.24, 465.10 and 1566.96 keV γ transition intensities assuming the respective multipolarities to be pure El, E2 and E2.…”

“…The short half-life (T l/ 2 = 2.2 min) of 209 T1 does not make easy the radiochemical separation of the nuclide and up to now the y-ray spectrum has been measured only on 209 T1 sources in radioactive equilibrium with the 213 Bi precursor [1], or with 229 Th through the decay chain 229 Th (ti/2 = 7300 y)-» 225 Ra (i 1/2 = 14.9 d)^2 25 Ac (i 1/2 = 10.0d)-221 Fr 0i/2 = 4.8 m)-» 217 At (f 1/2 = 0.032 s)-+ 213 Bi (* 1/2 = 45.6 m). Only a cascade of 3γ-rays with equal transition intensity, decaying from the 2.150 MeV level of 209 Pb, was known from earlier studies [2,3].…”