Properties of high-spin states in $sup 95$Tc from $sup 93$Nb($alpha$,2n)$sup 95$Tc* ($gamma$) reaction spectrometry: A test of the cluster-core coupling model
The structure and properties of the high angular momentum states in $sup 95$Tc up to 5605 keV of excitation have been investigated via measurements of excitation functions of $gamma$ ray singles and $gamma$$gamma$ coincidences following the $sup 93$Nb($alpha$,2n)$sup 95$TC*($gamma$) reaction with $alpha$- particle energies between 17 and 30 MeV. From these experiments and from high- resolution singles energy, angular-distribution, and Doppler-shift attenuation measurements, the position and the decay properties of many high angular momentum state in $sup 95$Tc have been determined. Eleven levels with J/sup $pi$/ values were confirmed, and 14 new levels with J/sup $pi$/ values are proposed. Other possible levels are also suggested. The measured angular distributions provided (i) branching ratios, (ii) J/sup $pi$/ assignments corroborated by deduced angular-distribution attenuation coefficients, level excitation functions and side-feeding yields, and (iii) multipole mixing ratios delta (E2/M1). Lifetimes for nine high-spin levels and limits for four additional ones were obtained by the Doppler-shift attenuation method from measurements with the $sup 93$Nb($alpha$,2n)$sup 95$Tc* ($gamma$) reaction at 18.5, 20.6, 23.6 and 26.7 MeV. The lifetimes were extracted from singles spectra taken 0$sup 0$ and 90$sup 0$ by examining the dependence on E/sub $alpha$/ of the effective level lifetime. For many transitions B(E2) and B(M1) values were obtained. The present results are compared with calculations based on the coupling of three-quasiparticle (g$sub 9$/ $sub 2$$)$$sup 3$ configurations to the quadrupole vibrations of the core, and remarkable agreement is observed for states up to only 19/2$sup +$$sub 1$. This model fails to explain the properties of the higher-spin states with J/sup $pi$/ greater than or equal to 21/2$sup +$.
- Research Organization:
- Department of Chemistry, Washington University, St. Louis, Missouri 63130 and Research Institute for Physics, 104 05 Stockholm 50, Sweden
- NSA Number:
- NSA-33-004412
- OSTI ID:
- 4173997
- Journal Information:
- Phys. Rev., C, v. 12, no. 4, pp. 1176-1204, Other Information: Orig. Receipt Date: 30-JUN-76
- Country of Publication:
- United States
- Language:
- English
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642803*
*TECHNETIUM 95 ALPHA REACTIONS- ANGULAR DISTRIBUTION- COMPOUND- NUCLEUS REACTIONS- ENERGY SPECTRA- EXCITATION FUNCTIONS- GAMMA RADIATION- MEV RANGE 10-100- NEUTRONS- NIOBIUM 93
BRANCHING RATIO- CLUSTER MODEL- ENERGY- LEVEL TRANSITIONS- HIGH SPIN STATES- MIXING RATIO- MULTIPOLARITY- PARITY- PROBABILITY- SPIN