Positive-Parity Bands in 29Si

1971 ◽  
Vol 49 (10) ◽  
pp. 1263-1274 ◽  
Author(s):  
A. A. Pilt ◽  
R. H. Spear ◽  
R. V. Elliott ◽  
J. A. Kuehner
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Linear Polarization ◽  
Ground State ◽  
Gamma Ray ◽  
Positive Parity ◽  
Rotational Bands ◽  
Mixing Ratios ◽  
First Excited State ◽  
Nilsson Model

A study has been made of several high spin members of the ground state (Kπ = 1/2+) and first-excited state (Kπ = 3/2+) rotational bands in the presumed oblate nucleus 29Si. Gamma-ray angular distribution and linear polarization measurements have confirmed the spin and parity of the 4081 keV level to be 7/2+, and levels at 4742 and 5283 keV have been shown to have Jπ = 9/2+ and (7/2+, 3/2+) respectively. Branching and mixing ratios for the transitions from these states have also been determined; in conjunction with previously measured lifetimes, transition strengths are calculated. The results are compared with the predictions of a Nilsson-model calculation including the effects of coriolis mixing of the low-lying positive parity bands.

THE SPIN OF THE 3.70-MEV LEVEL IN Al25

1963 ◽  
Vol 41 (6) ◽  
pp. 923-931 ◽  
Author(s):  
G. J. McCallum
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Band Structure ◽  
Ground State ◽  
Transition Probability ◽  
Spin Assignment ◽  
Mixing Ratio ◽  
Excitation Radiation ◽  
Rotational Bands ◽  
First Excited State

The 3.70-Mev level in Al25 has been studied by means of the reaction Mg24(p, γ)Al25 at the 1.49-Mev resonance. Direct angular distribution measurements of the de-excitation gamma radiation support the spin assignment of 7/2− for this level. An E2/M1 amplitude mixing ratio of −0.55 ± 0.2 is found for the 1.79-Mev de-excitation radiation from the fourth excited state to the ground state of Al25. The ratio of the reduced transition probability of the E2 radiation from the 1.79-Mev level to the first excited state is shown to be ~30 times that to the ground state. This result provides further confirmation of rotational band structure in Al25 since the collective model predicts such an enhancement of E2 transitions between rotational bands whereas cross-band transitions are not expected to be enhanced.

Nuclear alinement of manganese-56

1959 ◽  
Vol 250 (1263) ◽  
pp. 550-561 ◽  
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Angular Correlation ◽  
Excited States ◽  
Daughter Nucleus ◽  
Γ Radiation ◽  
Mixing Ratios ◽  
First Excited State ◽  
Γ Rays ◽  
Coincidence Measurements

The present work demonstrates the feasibility of alining manganese-56 produced by neutron irradiation of a nickel fluosilicate crystal containing stable 55 Mn. Measurements were made of the angular distribution of the γ-radiation from the alined 56 Mn and also of the angular correlation of the γ-rays from this isotope. By combining the results it is possible to establish uniquely as 2 the spins of the states of the daughter nucleus of 56 Fe at 2.66 and 2.98 MeV. The mixing ratios δ ( E 2/ M 1) for the 1.81 and 2.13 MeV γ-rays to the first excited state are shown to be 0.19 ± 0.02 and — 0.28 ± 0.02. The spectrum of the γ-radiation was studied with a scintillation spectrometer and this leads to the following relative intensities; 0.845 MeV (100%), 1.81 MeV (27 ± 3%), 2.13 MeV (15 ± 3%), 2.55 MeV (1.2 ± 0.2%), 2.66 MeV (0.65 ± 0.1%), 2.98 MeV (0.35 ± 0.1%) and 3.4 MeV (0.22 ± 0.05%). Coincidence measurements suggest that the 2.55 and 3.4 MeV γ-rays are due to de-excitation of a level at about 3.4 MeV which decays both to the ground and first excited states. A spin of 2 for this state is proposed.

Proton?Capture Gamma Rays from Nitrogen?13

1962 ◽  
Vol 15 (3) ◽  
pp. 443 ◽  
Author(s):  
AW Parker ◽  
GG Shute
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Elastic Scattering ◽  
Gamma Rays ◽  
Ground State ◽  
Recent Experiment ◽  
Gamma Ray ◽  
Angular Distributions ◽  
Proton Capture ◽  
Yield Curves

From a recent experiment in this laboratory (Shute et al. 1962) on the elastic scattering of protons from 12C, resonance levels (E13N, J1t) of 13N were obtained at the laboratory bombarding energies (Ep) shown in Table 1. To confirm these results, an investigation of the yield and angular distribution of gamma rays from the reaction 12C(p'YO)13N and 12C(p'Yl)13N was undertaken. Accordingly, the theoretical angular distributions, W(8), for the gamma ray (Yo) to the ground state of 13Na-) and also for the gamma ray (Yl) to the 1st excited state of 13Na+) were evaluated on the assumptions that overlap of levels in 13N is small and lowest order multipoles are involved. As angular distributions are parity insensitive, these were found to be identical for the two gamma rays expected. The simpler of these angular distributions are also shown on the table. The expected angular distributions indicate that 90� is a suitable angle for yield curves.

Gamma-Ray Linear Polarization and Angular Distribution Formulas in Terms of Phase-Defined Reduced Matrix Elements

1971 ◽  
Vol 49 (3) ◽  
pp. 328-351 ◽  
Author(s):  
P. Taras
Keyword(s):  
Angular Distribution ◽  
Linear Polarization ◽  
Gamma Ray ◽  
Polarization Measurement ◽  
Recent Measurement ◽  
Full Potential ◽  
Matrix Elements ◽  
Mixing Ratios ◽  
Nuclear Models

Gamma-ray linear polarization and angular distribution formulas are presented in terms of the phase-defined reduced matrix elements of Rose and Brink. In particular, the mixing ratios are phase consistently related to reduced matrix elements of interaction multipole operators which are also well defined in phase. The mixing ratios extracted from the measurements of gamma-ray angular distribution and linear polarization can then be compared in both magnitude and sign with the predictions of nuclear models. The full potential of a gamma-ray linear polarization measurement is demonstrated by the discussion of a recent measurement.

THE ANGULAR DISTRIBUTION OF GAMMA RAYS IN THE C12(p,p′γ) REACTION

1953 ◽  
Vol 31 (2) ◽  
pp. 189-193 ◽  
Author(s):  
H. E. Gove ◽  
N. S. Wall
Keyword(s):  
Angular Momentum ◽  
Angular Distribution ◽  
Excited State ◽  
Proton Beam ◽  
Gamma Rays ◽  
Ground State ◽  
Expansion Formula ◽  
First Excited State ◽  
Incoming Proton

Protons of 7.1 Mev. energy from the MIT cyclotron have been used to investigate the angular distribution of gamma rays from the C12(p,p′γ) reaction with respect to the incoming proton beam. These gamma rays result from transitions between the first excited state of C12 at 4.45 Mev. and the ground state. The resulting distribution can be fitted by the expansion[Formula: see text]which is consistent with an assignment of two for the angular momentum of the first excited state of C12.

PROPERTIES OF LEVELS AT 6.69 AND 6.88–6.89 MeV IN 28Si

1966 ◽  
Vol 44 (5) ◽  
pp. 1087-1097 ◽  
Author(s):  
R. J. A. Levesque ◽  
R. W. Ollerhead ◽  
E. W. Blackmore ◽  
J. A. Kuehner
Keyword(s):  
Excited State ◽  
Alpha Particle ◽  
Ground State ◽  
State Transition ◽  
Gamma Ray ◽  
The Other ◽  
Ground State Transition ◽  
Angular Correlations ◽  
First Excited State ◽  
Strong Ground

Levels at 6.69, 6.88, and 6.89 MeV were observed in the 16O(16O, α)28Si reaction, and angular correlations were measured for the resulting gamma-ray transitions, using the geometry in which the alpha particle is detected at 0°. The level at 6.69 MeV had not been reported previously and was assigned spin and parity 0+. The doublet of levels at 6.88–6.89 MeV was not resolved in these measurements, but angular correlations of the gamma-ray transitions were possible, using spectrum subtraction techniques. One member of the doublet, previously assigned spin 3, has a strong ground-state transition; the angular correlation for this transition confirms a 3− assignment to this level. The other member of the doublet, which decays almost entirely to the first excited state, could not be assigned a spin on the basis of these measurements. However, taken in conjunction with other measurements, an assignment of 4+ is favored.

Properties of the levels in 22Na deduced from the 19F(α,nγ)22Na reaction

1976 ◽  
Vol 54 (11) ◽  
pp. 1134-1148 ◽  
Author(s):  
J. D. MacArthur ◽  
A. J. Brown ◽  
P. A. Butler ◽  
L. L. Green ◽  
C. J. Lister ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Spherical Shell ◽  
Shell Model ◽  
Gamma Rays ◽  
Linear Polarization ◽  
Experimental Information ◽  
Positive Parity ◽  
Model Program ◽  
Rotational Bands ◽  
Mean Lifetimes

For gamma rays following the 19F(α,nγ)22Na reaction, angular distribution, linear polarization, and DSA measurements have been analysed to extend the experimental information on the rotational bands in 22Na. In particular the spins, parities, and mean lifetimes of the following states belonging to the indicated bands have been determined; (Ex, Jπ, τm, K); 3.707 MeV, 6+, 110 ± 10 fs, K = 3+; 1.984 MeV, 3+, —, K = 0+; 4.710 MeV, 5+, 50 ± 20 fs, K = 0+; 4.071 MeV, 4+, —, K = 0+. In addition, the spins, parities and lifetimes of the 4.360, 5.063, and 5.100 MeV states were determined to be 2+, <10 fs; 2+, <20 fs; and 4+, 55 ± 15 fs respectively. Besides the known branches from the 4.710 MeV state, a 5 ± 1% branch to the 2.969 MeV state was observed; while for the 5.100 MeV state, branches of 18 ± 2, 15 ± 5, 12 ± 2, 18 ± 2, and 37 ± 3% were observed to the ground, 0.891, 1.528, 3.060, and 4.071 MeV states. All the positive parity states below 5.1 MeV have been interpreted in terms of spherical shell model configurations for six particles in the s–d shell predicted by the Manchester–Glasgow shell model program, using the Preedom and Wildenthal interaction.

SOME PROPERTIES OF THE 2.23-MEV EXCITED STATE OF P31

1959 ◽  
Vol 37 (1) ◽  
pp. 53-62 ◽  
Author(s):  
A. E. Litherland ◽  
G. A. Bartholomew ◽  
H. E. Gove ◽  
E. B. Paul
Keyword(s):  
Angular Momentum ◽  
Excited State ◽  
Gamma Rays ◽  
Ground State ◽  
Total Angular Momentum ◽  
Gamma Ray ◽  
Triple Correlation ◽  
Compound State ◽  
First Excited State ◽  
Coincidence Measurements

The 2.23-Mev excited state of P31 has been studied by means of the capture gamma rays from the 1.70-Mev resonance in the reaction Si30(pγ)P31. The angular correlation of the ground state gamma ray established that the resonance had total angular momentum 3/2, and triple correlation measurements of the cascading gamma rays from the compound state showed that the angular momentum of the 2.23-Mev state was 5/2. Coincidence measurements showed that the cascade gamma rays from the 2.23-Mev state to the first excited state at 11.27-Mev were [Formula: see text] of the transitions to the ground state.

GAMMA RADIATION FROM THE PROTON BOMBARDMENT OF OXYGEN

1954 ◽  
Vol 32 (9) ◽  
pp. 563-570 ◽  
Author(s):  
J. B. Warren ◽  
K. A. Laurie ◽  
D. B. James ◽  
K. L. Erdman
Keyword(s):  
Excited State ◽  
Gamma Radiation ◽  
Ground State ◽  
Gamma Ray ◽  
Radiative Transition ◽  
Proton Bombardment ◽  
First Excited State ◽  
Main Transition ◽  
Bombarding Energy ◽  
Three Components

The nuclear gamma radiation following the non-resonant capture of a proton in O16 has been studied with protons of energies, from 800 kev. to 2.1 Mev. and found to consist of three components. The main transition goes, via a gamma ray of energy that varies with proton bombarding energy, to the [Formula: see text] state of F17. This state, 487 kev. above the ground state, radiates directly to the ground state. In addition there is a weaker direct radiative transition from the capture configuration to the ground state. At energies above Ep = 1.8 Mev. oxide targets bombarded with protons give rise to a radiation of 873 kev. attributed to the presence of the O17 isotope via the reaction O17(p, p′)O17*, the radiation corresponding to the transition from the first excited state of O17 to the ground state.

35C1 AND THE UNIFIED MODEL

1966 ◽  
Vol 44 (7) ◽  
pp. 1563-1572 ◽  
Author(s):  
P. Taras
Keyword(s):  
Excited State ◽  
Ground State ◽  
Negative Parity ◽  
Unified Model ◽  
Experimental Results ◽  
Positive Parity ◽  
Rotational Bands ◽  
The Third

The experimental results obtained for 35Cl are interpreted in terms of the unified model. Members of live rotational bands can be identified. The band based on the ground state can be assigned K = 3/2 and positive parity. Of the three excited-state bands, two have positive parity and K = 1/2, while the third one has negative parity and K = 7/2.

Sign in / Sign up

Export Citation Format

Share Document