scholarly journals A Search for an Excited Kp=0+ Rotational Band in 24Mg

1976 ◽  
Vol 29 (3) ◽  
pp. 139 ◽  
Author(s):  
D Branford ◽  
LE Carlson ◽  
FCP Huang ◽  
N Gardner ◽  
TR Ophel ◽  
...  
Keyword(s):  
Shell Model ◽  
Quadrupole Moment ◽  
Rotational Band ◽  
Doppler Shift ◽  
Transition Rates ◽  
Model Calculations ◽  
Doppler Shift Attenuation ◽  
Doppler Shift Attenuation Method ◽  
Absolute Transition ◽  
Good Agreement

A search is described for an excited Kn = 0+ rotational band based on the 6� 44 MeV level of 24Mg. Mean nuclear lifetimes have been measured by the Doppler shift attenuation method using the 12C('60,a)24Mg reaction and the results are 't'm = 66�29, 28�7 and 13�3 fs for levels at 6'44, 8�65 and 10� 58 MeV respectively. The absolute transition rates found for the y decays from the 6�44 and 8�65 MeV levels are in good agreement with the results of shell model calculations if it is assumed that these levels are the 0+ and 2 + members respectively of the excited Kn = 0+ rotational band. Based on this assumption, a result Qoo = 0�48 �0�08b is obtained for the intraband quadrupole moment. From a study of the 23Na(p, y) reaction, it is established that the J = 4 levels at 12� 63 and 13�05 MeV do not decay by enhanced E2 transitions to the 8� 65 MeV level. This suggests that neither of these levels is the 4 + member of the excited Kn = 0+ rotational band. An assignment of J" = 4+ is made to one member of the doublet at 10�58 MeV.

Transition rates in 29P

1970 ◽  
Vol 48 (22) ◽  
pp. 2683-2691 ◽  
Author(s):  
C. F. Monahan ◽  
H. C. Evans ◽  
J. H. Montague ◽  
W. R. Paulson ◽  
W. M. Zuk
Keyword(s):  
Excited States ◽  
Gamma Rays ◽  
Doppler Shift ◽  
Resonance Level ◽  
Transition Rates ◽  
Mixing Ratios ◽  
Doppler Shift Attenuation ◽  
The Mean ◽  
Doppler Shift Attenuation Method ◽  
Mean Lifetimes

Lifetimes of three of the low-lying excited states in 29P, populated in the 28Si(p,γ) reaction, have been determined using the Doppler shift attenuation method. The mean lifetimes of states at 4.085, 1.956, and 1.385 MeV were found to be 15 ± 4, 370 ± 80, and 200 ± 60 fs.Angular distribution measurements have also been performed on gamma rays resulting from the decay of the 4.085 MeV resonance level. The decay was found to go via states at 3.107 MeV (3%), 1.956 MeV (54%), and 1.385 MeV (43%). The spin of the resonance level was uniquely assigned as 7/2 and the multipole mixing ratios of the 2.129 and 1.385 MeV transitions as + 0.17 ± 0.05 and + 0.303 ± 0.050 respectively. The consequent transition rates indicate that the parity of the resonance level is positive.

LIFETIME MEASUREMENTS OF STATES IN O18 AND Ne22

1964 ◽  
Vol 42 (6) ◽  
pp. 1311-1323 ◽  
Author(s):  
M. A. Eswaran ◽  
C. Broude
Keyword(s):  
Excited State ◽  
Ground State ◽  
Doppler Shift ◽  
State Transition ◽  
Branching Ratios ◽  
Ground State Transition ◽  
Lifetime Measurements ◽  
Doppler Shift Attenuation ◽  
First Excited State ◽  
Doppler Shift Attenuation Method

Lifetime measurements have been made by the Doppler-shift attenuation method for the 1.98-, 3.63-, 3.92-, and 4.45-Mev states in O18 and the 1.28-, 3.34-, and 4.47-Mev states in Ne22, excited by the reactions Li7(C12, pγ)O18 and Li7(O16, pγ)Ne22. Branching ratios have also been measured. The results are tabulated.[Formula: see text]The decay of the 3.92-Mev state in O18 is 93.5% to the 1.98-Mev state and 6.5% to the ground state and of the 4.45-Mev state 74% to the 3.63-Mev state, 26% to the 1.98-Mev state, and less than 2% to the ground state. In Ne22, the ground-state transition from the 4.47-Mev state is less than 2% of the decay to the first excited state.

Lifetime measurements by the Doppler-shift attenuation method in theSn115(α,nγ)Te118reaction

2011 ◽  
Vol 83 (5) ◽  
Author(s):  
C. Mihai ◽  
A. A. Pasternak ◽  
S. Pascu ◽  
D. Filipescu ◽  
M. Ivaşcu ◽  
...  
Keyword(s):  
Doppler Shift ◽  
Lifetime Measurements ◽  
Doppler Shift Attenuation ◽  
Doppler Shift Attenuation Method

Mesures de vies moyennes dans 12B, 14N et 16O

1970 ◽  
Vol 48 (13) ◽  
pp. 1595-1606 ◽  
Author(s):  
A. Gallmann ◽  
F. Haas ◽  
N. Balaux ◽  
B. Heusch ◽  
M. Toulemonde
Keyword(s):  
Wave Function ◽  
Doppler Shift ◽  
Partial Width ◽  
Transition Energies ◽  
Radiative Transitions ◽  
Upper Limits ◽  
Doppler Shift Attenuation ◽  
Theoretical Predictions ◽  
Doppler Shift Attenuation Method ◽  
Gamma Radiations

Lifetimes of nuclear states have been measured by the Doppler-shift attenuation method. Gamma radiations from the 11B(d,pγ)12B, 19F(p,αγ)16O, and 12C(h,pγ)14N reactions were observed with a Ge(Li) detector at θγ = 7°, 90° and 173°. The following lifetimes were obtained:[Formula: see text]Upper limits have been set for very fast lifetimes, and transition energies were also determined. The partial widths of the radiative transitions from the 6.44 MeV state of 14N were compared with theoretical predictions. The amplitude of a (p3/2)−2 configuration in the wave function of this level was evaluated using the partial width of the 6.44 → 3.95 MeV transition determined in the present work.

55 YEARS OF THE SHELL MODEL: A CHALLENGE TO NUCLEAR MANY-BODY THEORY

2005 ◽  
Vol 14 (06) ◽  
pp. 821-844 ◽  
Author(s):  
IGAL TALMI
Keyword(s):  
Shell Model ◽  
Wave Functions ◽  
Many Body ◽  
Apparent Absence ◽  
Model Calculations ◽  
Many Body Theory ◽  
Body Theory ◽  
Nuclear Many Body Theory ◽  
Closed Shells ◽  
Good Agreement

Shell model calculations of nuclear energies and wave functions of nucleons outside closed shells interacting by effective two-body forces yield good agreement with much experimental data. Many attempts have been made to calculate nuclear energies ab initio, by starting from some form of an interaction between free nucleons. Recent results of such calculations claim to obtain reasonable agreement with measured energies. These results, however, are obtained for wave functions which are very complicated. It is difficult to see how such wave functions are consistent with independent nucleon motion, the very essence of the shell model. In some of those calculations, 3-body interactions play a very important role. This is puzzling since nuclear energies are accurately obtained in shell model calculations by using only effective two-body interactions. In this paper, some examples of simple shell model calculations are reviewed. They exhibit good agreement with experiment and the apparent absence of the need for effective 3-body interactions.

Measurement of lifetimes of nuclear excited states by doppler shift attenuation method

1964 ◽  
Vol 8 (1) ◽  
pp. 52-53 ◽  
Author(s):  
M.A. Eswaran ◽  
H.E. Gove ◽  
A.E. Litherland ◽  
C. Broude
Keyword(s):  
Excited States ◽  
Doppler Shift ◽  
Doppler Shift Attenuation ◽  
Doppler Shift Attenuation Method

scholarly journals Shell Model Calculations for 18,19,20O Isotopes by Using USDA and USDB Interactions

2018 ◽  
Vol 63 (3) ◽  
pp. 189 ◽  
Author(s):  
A. K. Hasan
Keyword(s):  
Shell Model ◽  
Empirical Data ◽  
Transition Probabilities ◽  
Energy Levels ◽  
Model Space ◽  
Magic Nucleus ◽  
Model Calculations ◽  
O Isotopes ◽  
Good Agreement

The shell model (SM) is used to calculate the energy levels and transition probabilities B(E2) for 18,19,20 O isotopes. Two interactions (USDA and USDB) are used in the SDPN model space. We assume that all possible many-nucleon configurations are defined by the 0d5/2, 1s1/2, and d3/2 states that are higher than in 16 O doubly magic nucleus. The available empirical data are in a good agreement with theoretical energy levels predictions. Spins and parities were affirmed for new levels, and the transition probabilities B(E2; ↓) are predicted.

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