Photon scattering experiments on the quasistable, odd-odd mass nucleusLu176

Properties of the5−state at 839 keV inLu176and theMohr1, Bisterzo2, Gallino3 et al. 2009Phys. Rev. CSelf Cite252300View full textAdd to dashboardCite

“…However, this assignment to the lowest IS has a rather large uncertainty because the IS at 1330 ± 30 keV is located very close to the 60 Co energy of 1332 keV. Additionally, a tentative state in 176 Lu has been seen in photon scattering [6] at 1332 keV. If there is accidental overlap between the primary 60 Co energy and the excitation energy of an IS in 176 Lu, then the yield in the 60 Co photoactivation experiments [10,15,16,17] However, the limit from γ-spectroscopy is a combined limit from two independent measurements of the branching ratio and the lifetime.…”

“…The combined result is 10 ps ≤ τ ≤ 433 ps (3.5) Note that the half-life t 1/2 ≤ 300 ps has been determined in the original work [19] which is later cited -probably in error -as lifetime τ ≤ 300 ps [1,18,20]. A recent photon scattering experiment [6] did not see the IS at 839 keV; from the experimental limits τ ≥ 1.5 ps could be derived which does not further restrict the allowed range for the lifetime τ in Eq. (3.5).…”

“…A very tentative assignment can be suggested for the kink at 1330 keV. It may correspond (i) to the 1332 keV level seen in photon scattering and thus coupled to the ground state [6] or (ii) to a level at 1301 keV seen in the 176 Yb(p,n) 176 Lu reaction [22] which is coupled to the isomer. A few levels around the IS at 1660 keV are reported in [27] at 1617 keV, 1655 keV, 1679 keV, 1689 keV, and 1693 keV; however, for two of these levels not even a spin/parity assignment has been adopted in [27].…”

“…Photon scattering [6] and photoactivation of 176 Lu [7] have been measured using bremsstrahlung at the Stuttgart dynamitron, and earlier experiments with bremsstrahlung have been performed using medical and technical electron accelerators [8,9,10,11] which are known to provide high photon intensities [12]. Activation after Coulomb excitation was studied at the Tandem accelerator at IPN, Orsay [13], activation using positron annihilation was measured at the Kyoto research reactor [14], and photoactivation experiments with various radioactive sources were reported in [10,15,16,17].…”

Review of metastable states in heavy nuclei

“…Furthermore, photo-excitation via higher-lying intermediate-K states provides a dual pathway (7 − →0 − or 0 − →7 − ) which can depopulate or populate the long-lived ground state. Together with the initial neutron-capture rates, these factors affect the production rates of 176 Lu and its hafnium daughter [33,371,375,35]. Evidence from nuclear spectroscopy for the existence of intermediate states which could play a role in this process is still fragmentary and a consensus has not been reached (see for example Ref.…”