Properties of the 1.410 and 1.612 MeV Levels in 37Ar and the 1.727 MeV Level in 37Cl

1971 ◽  
Vol 49 (9) ◽  
pp. 1215-1224 ◽  
Author(s):  
P. Taras ◽  
A. Turcotte ◽  
R. Vaillancourt ◽  
J. Matas
Keyword(s):  
Angular Distribution ◽  
Gamma Rays ◽  
Linear Polarization ◽  
Single Particle ◽  
Ground State ◽  
Incident Proton ◽  
Mixing Ratio ◽  
Single Particle Excitation ◽  
Decay Gamma

The properties of the 1.410 and 1.612 MeV levels in 37Ar and the 1.727 MeV level in 37Cl were investigated. The levels in 37Ar were populated via the 37Cl(p,n)37Ar reaction and the level in 37Cl via the 37Cl(p,p′)37Cl reaction. The angular distribution and the linear polarization of the decay gamma rays of these levels were measured at incident proton energies of 3.98, 4.17, 4.38, and 4.81 MeV. The results of these measurements are consistent with a spin of 1/2 for the 1.410and 1.727 MeV levels, while they definitely establish the spin and parity of the 1.612 MeV level to be 7/2−. This last level has also been found to decay entirely to the ground state, with a multipolarity mixing ratio δ(E3/M2) = +0.22 ± 0.11. This level has properties quite similar to those of the 7/2− states in 35Cl and 37Cl, indicating that they may all arise from a 1f7/2 single-particle excitation.

Study of Low-Lying Levels in 37Ar

1972 ◽  
Vol 50 (11) ◽  
pp. 1182-1194 ◽  
Author(s):  
P. Taras ◽  
A. Turcotte ◽  
R. Vaillancourt
Keyword(s):  
Angular Distribution ◽  
Gamma Rays ◽  
Linear Polarization ◽  
Ground State ◽  
Solar Neutrino ◽  
Gamma Ray ◽  
Capture Rate ◽  
Mixing Ratio ◽  
Excitation Energies ◽  
Decay Gamma

The properties of the first five excited levels in 37Ar were investigated via the 37Cl(p,n)37Ar reaction at Ep = 3.98, 4.17, 4.38, and 4.81 MeV and via the 34S(α,n)37Ar reaction at Eα = 8.00, 8.50, and 8.60 MeV. The following excitation energies were obtained: Ex = 1409.7 ± 0.4, 1611.5 ± 0.4, 2217.8 ± 0.8, 2491.4 ± 0.8, and 2797.0 ± 0.8 keV. These levels were found to decay almost entirely to the ground state. The angular distribution and the linear polarization of the decay gamma rays of these levels were measured. From these measurements definite spin–parity assignments as well as values of the mixing ratio of the ground state gamma-ray transitions were obtained. These are: Ex(Jπ, δ) = 1612 ([Formula: see text], +0.11 ± 0.02), 2218 ([Formula: see text], 0.0 ± 0.02), 2491 ([Formula: see text]), and 2797 ([Formula: see text], −0.16 ± 0.03 or +8.0 ± 1.5, the value of −0.16 being more probable). The measurements were also consistent with a spin of [Formula: see text] for the 1410 keV level. The results are compared with a recent shell-model calculation and are discussed in the context of the solar neutrino capture rate in 37Cl.

Properties of the 1.763 MeV level in 35Cl

1969 ◽  
Vol 47 (15) ◽  
pp. 1605-1616 ◽  
Author(s):  
P. Taras ◽  
J. Matas
Keyword(s):  
Angular Distribution ◽  
Beta Decay ◽  
Linear Polarization ◽  
Ground State ◽  
Unified Model ◽  
Mixing Ratio ◽  
Polarization Measurements ◽  
Good Agreement

Angular distribution and linear-polarization measurements have been performed at the Ep = 3.115 and 3.345 MeV resonances in the reaction 35Cl(p,p′γ)35Cl. The spin and parity of the 1.763 MeV level in 35Cl have been deduced to be 5/2+ while the multipolarity mixing ratio of its decay to the ground state has been found to be δ(E2/M1) = +2.64 ± 0.12. These results confirm that the possible E1 transition from the 3.163 to the 1.763 MeV level in 35Cl is inhibited by a factor of at least 108. The properties of the 1.763 MeV level and the beta decay from 35Ar to the first three levels in 35Cl are found to be in quite good agreement with the predictions of the unified model.

Study of the 1459-keV level in 19F by the 19F(p,p′γ)19F reaction

1970 ◽  
Vol 48 (7) ◽  
pp. 827-833 ◽  
Author(s):  
S. T. Lam ◽  
A. E. Litherland ◽  
J. J. Simpson
Keyword(s):  
Angular Distribution ◽  
Single Crystal ◽  
Linear Polarization ◽  
Proton Energy ◽  
Branching Ratios ◽  
Mixing Ratio ◽  
Γ Ray ◽  
Good Agreement

The 1459-keV level of 19F was populated by the 19F(p,p′γ)19F reaction at a proton energy of 2.78 MeV. The E2/M1 mixing ratio for the 1459 → 110 keV transition was determined to be [Formula: see text] from a combination of the γ-ray angular distribution and linear polarization and the nuclear lifetime. The γ-ray angular distribution was measured with a coaxial Ge(Li) detector and the γ-ray linear polarization with a planar Ge(Li) detector. The corresponding E2 and M1 transition strengths for a lifetime of 0.084 ± 0.020 ps are found to be [Formula: see text] and 0.10 ± 0.03 W.u. respectively. They are in good agreement with the particle–hole calculations of Benson and Flowers. The branching ratios of the 1459-keV level agree well with those of Poletti et al. The γ-ray transitions from the 1459-keV level provide a good example for demonstrating the usefulness of a single crystal Ge(Li) polarimeter.

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.

Angular distribution and linear polarization of the gamma rays from oriented 56Co nuclei

1958 ◽  
Vol 5 ◽  
pp. 58-88 ◽  
Author(s):  
A.N. Diddens ◽  
W.J. Huiskamp ◽  
J.C. Severiens ◽  
A.R. Miedema ◽  
M.J. Steenland
Keyword(s):  
Angular Distribution ◽  
Gamma Rays ◽  
Linear Polarization

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.

Properties of 11.05 MeV state in 14N

1980 ◽  
Vol 58 (1) ◽  
pp. 150-152 ◽  
Author(s):  
C. Rangacharyulu ◽  
C. St-Pierre
Keyword(s):  
Angular Distribution ◽  
Single Particle ◽  
Ground State ◽  
Natural Width ◽  
Excitation Functions ◽  
Resonance Spin ◽  
Gamma Decay

The gamma decay of Ep = 3.77 MeV resonance in 13C(p,γ)14N has been measured. From the measured excitation functions, the natural width of the resonance was deduced to be 1.2 ± 0.4 keV. The resonance is found to strongly populate the 3.945 MeV level, in addition to the gs transition. Gamma angular distribution measurements determined the resonance spin as 3+. The reduced proton width is found to be 0.5% of the single particle unit. The transition strengths are measured to be B(E2) = 0.45 ± 0.07 and 3.0 ± 0.8 Wu for transitions to ground state and the level at 3.945 MeV, respectively.

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.

Gamma rays from the 3702 keV level in 25Al

1969 ◽  
Vol 47 (23) ◽  
pp. 2609-2619 ◽  
Author(s):  
N. Anyas-Weiss ◽  
A. E. Litherland
Keyword(s):  
Angular Distribution ◽  
Lower Limit ◽  
Gamma Rays ◽  
Doppler Shift ◽  
Gamma Ray ◽  
Decay Modes ◽  
Mirror Nucleus ◽  
Mixing Ratios ◽  
Doppler Shift Attenuation ◽  
Decay Gamma

The decay modes of the 7/2−, 3702 keV level in 25Al have been studied at the Ep = 1490 keV resonance in the 24Mg(p,γ)25Al reaction. The decay gamma rays were observed using a 25 cm3 Ge(Li) detector. A previously unreported 2% transition from the resonance to the level at 2723 keV has been observed. The angular distribution of this gamma ray admits only a spin of 7/2 for the 2723 keV level. The lifetime of the 2723 keV level was measured with the Doppler shift attenuation method (DSAM) at the 1660 keV resonance and was found to be [Formula: see text]. The lifetime of the 5/2+, 1790 keV level has been measured using the DSAM and has been found to be [Formula: see text]. From Doppler shift measurements a lower limit for the lifetime of the 3/2+, 945 keV level of [Formula: see text] was obtained. From angular distribution measurements at the Ep = 1490 keV resonance, the following multipole mixing ratios have been measured: δ(R → 0) = 0.00 ± 0.02; δ(R → 1790) = −0.02 ± 0.02; δ(R → 2723) = 0.15 ± 0.30; [Formula: see text]; δ(1790 → 945) = −0.15 ± 0.05; δ(945 → 0) = 0.35 ± 0.10 or 1.7 ± 0.2; δ(945 → 451) = −0.15 ± 0.05 or 2.6 ± 0.4. Comparisons with data in the mirror nucleus 25Mg have been made.

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.

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