High spin states in /sup 163/Lu and /sup 165/Lu and backbending in rare earth nuclei

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:5138864

Rosenthal, M S

Since the observation of a band crossing at a rotation frequency of 0.27 MeV/h in the yrast cascade of several nuclei in the region of A = 160, much work, both experimental and theoretical, has been done to study this effect and its underlying cause. A second backbend has also been seen at around spin 28 (angular frequency 0.42 MeV/h) in the N = 90 even -Z isotones /sup 158/Er, /sup 160/Yb, and /sup 162/Hf, and is thought to arise from the breaking of an h/sub 11/2/ proton pair and the subsequent alignment of the protons' angular momenta along the rotation axis. In order to further understand the mechanism of the second backbend, a study of the odd -Z isotopes /sup 163/Lu (N = 92) and /sup 165/Lu (N = 94) was undertaken in order to: determine their level schemes, with the hope of getting to a high enough excitation energy so that the blocking of the second backbend might be observed, determine the change in alignment of the first backbend and the amount of alignment of the S-band compared to the S-bands of the neighboring even -A isotones, and compare these results with Cranked shell Model (CSM) calculations on /sup 163/Lu and /sup 165/Lu with the hope of better understanding the cause of the second discontinuity. /sup 163/Lu and /sup 165/Lu were populated via the /sup 148/Sm(/sup 19/F,4n..gamma..) and /sup 150/Sm(/sup 19/F,4n..gamma..) reactions, respectively, at E = 80-105 MeV using standard gamma-ray spectroscopy techniques. In both /sup 163/Lu and /sup 165/Lu the yrast level scheme appears to be based on the 7/2-(523) Nilsson orbital, with a band crossing at 0.27MeV/h. Also, it is found that in these nuclei the band crossing is sharper than that seen in the N = 90 nuclei, indicating a smaller interaction of the ground state band with the S-band.

• Research Organization: Yale Univ., New Haven, CT (USA)
• OSTI ID: 5138864
• Country of Publication: United States
• Language: English

Related Subjects

651823* -- Nuclear Properties & Reactions
A=150-189
Experimental-- Energy Levels & Transitions-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BACKBENDING
BETA DECAY RADIOISOTOPES
CHARGED-PARTICLE REACTIONS
CRANKING MODEL
DATA
DIRECT REACTIONS
ENERGY LEVELS
EXPERIMENTAL DATA
FLUORINE 19 REACTIONS
GAMMA SPECTRA
HEAVY ION REACTIONS
HIGH SPIN STATES
INFORMATION
INTERMEDIATE MASS NUCLEI
ISOTOPES
KNOCK-OUT REACTIONS
LUTETIUM 163
LUTETIUM 165
LUTETIUM ISOTOPES
MATHEMATICAL MODELS
MINUTES LIVING RADIOISOTOPES
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
SAMARIUM 148 TARGET
SHELL MODELS
SPECTRA
TARGETS
YRAST STATES