Decay Spectroscopy of Heavy Isotopes at SHIP Using the COMPASS Focal Plane Detection Set-up

Abstract

The new COMPASS detection system designed and developed at GSI, Darmstadt was employed in the focal plane of the SHIP velocity filter online during a period of commissioning. The isotope 254 No was initially measured for control purposes, following which the nuclei, 227,228,230 U, 229 Np, and 229,230 Pu were synthesized. The obtained data from α-decay spectroscopy is evaluated and compared with previous measurements.

Single-particle states and parity doublets in odd- Z Ac221 and Pa225 from Parr1, Smith2, Greenlees3 et al. 2022Phys. Rev. C5000View full textAdd to dashboardCite

“…The α decay of 221 Ac was previously studied several times in Refs. [10][11][12][13][14], with consistent results reported for αparticle energies and branching ratios for up to four α decays. Energies of excited states populated in 217 Fr following the α decays of 221 Ac, with [E α (keV), BR α (%)], were determined to be 210 (20) [7440 (15), 20 (5)], 270 (20) [7375 (10), 10(5)], and 485 (15) keV [7170 (10), ≈2].…”

“…No spin and parity assignments were made in Refs. [10][11][12][13][14] for the excited states in 217 Fr populated by 221 Ac α decay and the states were not observed in prompt γ -ray spectroscopy [15].…”

“…The α decay of 225 Pa has previously been reported in Refs. [10][11][12]14,16] with up to three decay branches. The α-particle energies and branching ratios measured in the more comprehensive of these studies were [7250 (20) [12].…”

Level structure of Ac221 and Fr217 from decay spectroscopy, and reflection asymmetry in Rey-Herme1, Raggio2, Vandebrouck3 et al. 2023Phys. Rev. C2000View full textAdd to dashboardCite

“…As mentioned above, there is a disagreement on the spin assignment of the ground state of 221 Ac between the inbeam [30] and α-decay [24] experiments. The α decay of 221 Ac has been studied several times in the past [24][25][26][27]29], with the most recent one [24] reporting three α-decay branches (see Table I) consistent with the previously measured ones, as well as three γ transitions measured in coincidence for the first time. In Ref.…”

“…The α decay of 225 Pa has previously been reported in several references [24][25][26][27][28][29]. The most extensive study [24], published recently, reports seven α-decay branches with energies, intensities and hindrance factors given in Table I, as well as four γ -ray transitions observed in coincidence for the first time.…”