Studies of Lawrencium Isotopes with Mass Numbers 255 Through 260
Abstract
Six isotopes of element 103, with mass numbers 255 through 260, have been studied by means of α-particle spectroscopy. The half-lives of the nuclides, and the energies and the intensities of their main α-particle groups were observed to be: <colspec colname="Col1"/><colspec colname="Col2"/><colspec colname="Col3"/> 255Lr 22 +/- 5 sec 8.37 +/- 0.02 MeV (~50%) 256Lr 31 +/- 3 sec 8.43 +/- 0.02 MeV (34 +/- 4%) 257Lr 0.6 +/- 0.1 sec 8.87 +/- 0.02 MeV (81 +/- 2%) 258Lr 4.2 +/- 0.6 sec 8.62 +/- 0.02 MeV (47 +/- 3%) 259Lr 5.4 +/- 0.8 sec 8.45 +/- 0.02 MeV (100%) 260Lr 180 +/- 30 sec 8.03 +/- 0.02 MeV (100%) A large number of target-projectile combinations were used in synthesizing the lawrencium isotopes. Representative excitation curves for producing the nuclides are displayed. Upper limits for decay by electron capture have been determined. α-decay hindrance factors have been calculated using the spin-independent equations of Preston. The α-decay energy systematics of the heaviest elements is discussed.
- Publication:
-
Physical Review C
- Pub Date:
- August 1971
- DOI:
- 10.1103/PhysRevC.4.632
- Bibcode:
- 1971PhRvC...4..632E