Collective and single particle behavior in selenium-75 and krypton-77

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1993

OSTI ID:6909301

Johnson, T D

High spin states in [sup 77]Kr were populated using the [sup 48]Ti([sup 32]S, 2pn)[sup 77]Kr reaction with a 106 MeV[sup 32]S beam from the Florida State University Tandem-LINAC accelerator. Three Compton-suppressed Ge detectors at 95[degrees] and one at 18[degrees] were used to determine [gamma]-[gamma] coincidences, directional correlation ratios and Doppler-shift attenuation lifetimes. Seven new transitions were added, extending the level scheme to new spin states of (45/2[sup +]) and 27/2[sup [minus]]; twenty-two new lifetimes were measured. High spin states of [sup 75]Se were investigated using the [sup 59]Co([sup 19]F,2pn)[sup 75]Se reaction at 55 MeV. Four Compton-suppressed detectors were used in this experiment; three placed at 90[degrees] and one at 25[degrees], for the determination of DCO ratios and lifetimes. Spin assignments were confirmed and mixing ratios were determined by measuring angular distributions with the reaction [sup 71]Ga([sup 7]Li,3n)[sup 75]Se at 25 MeV. Parity assignments were made from polarization measurements using the same reaction. The positive-parity band in [sup 75]Se has been extended to I[sup [pi]] = 19/2[sup [minus]]. Eleven new lifetimes were measured. A cranking model analysis was performed for both [sup 77]Kr and [sup 75]Se. A band crossing due to proton alignment was observed for the first time in [sup 75]Se. Quadrupole moments extracted from lifetimes, indicated significant collective behavior for both [sup 77]Kr and [sup 75]Se. The staggering of transition strengths coupled with signature splitting revealed the data to be consistent with largely a triaxial shape for [sup 75]Se and a more prolate shape for [sup 77]Kr.

• Research Organization: Florida State Univ., Tallahassee, FL (United States)
• OSTI ID: 6909301
• Country of Publication: United States
• Language: English

Related Subjects

663220* -- Electromagnetic Transitions-- (1992-)
663550 -- Nuclear Mass Ranges-- A=59-89-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
COLLECTIVE EXCITATIONS
CORRELATIONS
COUNTING TECHNIQUES
DAYS LIVING RADIOISOTOPES
DOPPLER EFFECT
DSA METHOD
ELECTRON CAPTURE RADIOISOTOPES
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EVEN-ODD NUCLEI
EXCITATION
HIGH SPIN STATES
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOTOPES
KRYPTON 77
KRYPTON ISOTOPES
LIFETIME
NUCLEI
OSCILLATION MODES
RADIOISOTOPES
SELENIUM 75
SELENIUM ISOTOPES
SINGLE-PARTICLE MODES