Multipole mixing ratios from polarized-beam gamma-ray singles measurements

1977 ◽  
Vol 15 (2) ◽  
pp. 829-830 ◽  
Author(s):  
H. T. King ◽  
M. Hass ◽  
R. Kaita ◽  
A. B. Robbins
Keyword(s):  
Gamma Ray ◽  
Mixing Ratios ◽  
Polarized Beam

Gamma-ray polarization measurements in 22Na

1970 ◽  
Vol 48 (20) ◽  
pp. 2434-2446 ◽  
Author(s):  
A. M. Baxter ◽  
B. W. J. Gillespie ◽  
J. A. Kuehner
Keyword(s):  
Single Crystal ◽  
Gamma Ray ◽  
Mixing Ratio ◽  
Spin Parity ◽  
Polarization Measurements ◽  
Mixing Ratios ◽  
Cast Doubt ◽  
Low Levels

The 19F(α,nγ)22Na reaction was studied using a Ge(Li) single-crystal polarimeter in addition to conventional Ge(Li) counters to elucidate certain spin, parity, and multipole-mixing ratio assignments to low levels of 22Na. The 1.984 MeV level, which had previously been assigned 2+ or 3+, has been shown not to be 3+ and, while 2+ is favored by the experiment, the evidence tends to suggest a problem in the interpretation of the properties of this level. The 2.572 MeV level is shown most likely to have spin and parity 2+. The J = 2 level at 3.059 MeV is clearly established as having even parity. In several cases limits on mixing ratios are obtained. These results cast doubt on certain model identifications made recently in 22Na.

Properties of low-lying states in 43Sc

1970 ◽  
Vol 48 (22) ◽  
pp. 2735-2750 ◽  
Author(s):  
G. C. Ball ◽  
J. S. Forster ◽  
F. Ingebretsen ◽  
C. F. Monahan
Keyword(s):  
Excited States ◽  
Gamma Ray ◽  
Level Structure ◽  
Surface Barrier ◽  
Angular Correlations ◽  
Mixing Ratios ◽  
Gamma Coincidence ◽  
Theoretical Predictions ◽  
Barrier Detector ◽  
Coincidence Spectra

The 40Ca(α, pγ)43Sc reaction at Eα = 11.8 to 15.5 MeV has been used to investigate the level structure of 43Sc below 4.2 MeV excitation. Level energies and decay schemes were determined from proton–gamma coincidence spectra obtained using an annular surface barrier detector positioned near 180° and two 40 cm3 Ge(Li) detectors. Angular correlations were measured in the same configuration using an array of six 12.7 × 15.2 cm NaI(Tl) detectors mounted on the Chalk River LOTUS goniometer. Twelve new levels were observed in 43Sc and information on the spins, branching ratios, and gamma-ray multipole mixing ratios of these and several other excited states has been obtained. The results are compared with recent theoretical predictions of Johnstone. In particular, levels at 1931 and 2552 keV, 1830 keV and 1883 keV have been tentatively assigned as the 9/2+ and probable 11/2+ members of the kπ = 3/2+ band, the (fp)3, Jπ = 11/2− state, and the 9/2− member of the kπ = 3/2− band, respectively.

Coulomb excitation of low-energy levels in 45Sc

1979 ◽  
Vol 57 (8) ◽  
pp. 1196-1203 ◽  
Author(s):  
V. U. Patil ◽  
R. G. Kulkarni
Keyword(s):  
Gamma Ray ◽  
Transition Probabilities ◽  
Coulomb Excitation ◽  
Energy Levels ◽  
Negative Parity ◽  
Core Excitation ◽  
Mixing Ratios ◽  
Reduced Transition Probabilities ◽  
Excitation Model ◽  
First Time

Low-lying negative parity levels in 45Sc were Coulomb excited with 2.5 to 3.5 MeV protons and 4 to 5 MeV 4He ions to test the weak coupling core-excitation model. A Ge(Li) detector was used to measure the gamma-ray yields. The 543, 976, 1408, and 1662 keV levels in 45Sc were Coulomb excited for the first time. Gamma-ray angular distributions were measured at 3.0 MeV proton energy in deducing multipole mixing ratios and spin values. Energy level measurements (in units of kiloelectronvolts) and spin values obtained are as follows: 976, 5/2, 7/2 and 1408, 7/2. The E2 and M1 reduced transition probabilities were determined for the six states. The 376, 720, 1237, 1408, and 1662 keV levels have properties consistent with the interpretation of coupling a 1f7/2 proton to the first 2+ core state.

(n,n′γ) studies of 114,116Cd

1980 ◽  
Vol 58 (1) ◽  
pp. 8-15 ◽  
Author(s):  
T. M. Newton ◽  
J. M. Davidson ◽  
W. K. Dawson ◽  
P. W. Green ◽  
H. R. Hooper ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Energy Levels ◽  
Angular Distributions ◽  
Mixing Ratios

Energy levels below 2.2 MeV excitation in 114,116Cd have been investigated using the (n, n′γ) reaction. Gamma-ray angular distributions were measured, and energy levels, spins, and gamma-ray multipole mixing ratios were deduced. Levels and their spins have been confirmed at 1134 (0), 1210 (2), 1283 (4), 1365 (2), 1733 (4), and 1843 (2) keV for 14Cd and at 1213 (2), 1220 (4), and 1381 (0) keV for 116Cd. New spin assignments have been made for the levels at 1861 (3) and 2049 (3) keV for 114Cd and at 1644 (2,3) and 1917 (3) keV for 116Cd. The states at 1959 keV in 114Cd and 1923 keV in 116Cd are shown to be consistent with assignments of 3.

AN ILLUSTRATION OF A TYPE OF TRIPLE CORRELATION MEASUREMENT WHICH CAN BE EASILY INTERPRETED

1960 ◽  
Vol 38 (7) ◽  
pp. 927-940 ◽  
Author(s):  
A. E. Litherland ◽  
G. J. McCallum
Keyword(s):  
Angular Correlation ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Residual Nucleus ◽  
Incident Beam ◽  
Electric Quadrupole ◽  
Final States ◽  
Angular Correlations ◽  
Mixing Ratios ◽  
Triple Correlation

The Mg26(He4, nγ)Si29 reaction has been used to illustrate the simplifications introduced in the interpretation of triple angular correlations by choosing a target and bombarding particles of zero spin and by observing the emitted particles, in this case neutrons, in a counter fixed at 0° to the beam. The angular correlations of the gamma rays with respect to the incident beam then depend only upon the properties of the final states in the residual nucleus. The angular correlation of the electric quadrupole 2.03-Mev gamma ray is predicted uniquely by theory and this prediction has been verified experimentally. The angular correlations of the 1.28-Mev and 2.43-Mev gamma rays have yielded for the E2/M1 amplitude mixing ratios +0.25 ± 0.05 or −3.4 ± 0.5 and −0.26 ± 0.08 or −1.10 ± 0.16 respectively. In addition, the experiment provides an illustration of the value of the recently discovered technique of neutron – gamma-ray discrimination in an organic scintillator.

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.

Coulomb excitation of 133Cs with protons

1985 ◽  
Vol 63 (4) ◽  
pp. 483-487 ◽  
Author(s):  
K. P. Singh ◽  
D. C. Tayal ◽  
B. K. Arora ◽  
T. S. Cheema ◽  
H. S. Hans
Keyword(s):  
Angular Distribution ◽  
Gamma Ray ◽  
Transition Probabilities ◽  
Coulomb Excitation ◽  
Spin Assignment ◽  
Thick Target ◽  
Angular Distributions ◽  
Distribution Data ◽  
Mixing Ratios ◽  
Reduced Transition Probabilities

Protons of energy 3.2–4.2 MeV have been used to Coulomb excite the states in 133Cs. The thick-target gamma-ray yields and the angular distributions were measured using a 50 cm3 Ge(Li) detector. The measurements were used to extract the reduced transition probabilities, B (E2) and B(M1), and multipole mixing ratios (δ) for the various transitions. A spin assignment has been made to the 871.8 keV level on the basis of angular distribution data. The results obtained have been compared with those of other authors.

Determination of mixing ratios for some cascades corresponding to 109Ag

1977 ◽  
Vol 55 (2) ◽  
pp. 175-179 ◽  
Author(s):  
H. E. Bosch ◽  
V. M. Silbergleit ◽  
M. Davidson ◽  
J. Davidson
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Angular Correlations ◽  
Mixing Ratios ◽  
Multichannel Analyzer ◽  
Level 3 ◽  
Gamma Ray Detector

An investigation of the gamma–gamma ray angular correlations following the decay of 109Pd was made by using a Ge(Li) semiconductor counter and NaI(Tl) gamma-ray detector. Coincidences measurements at six different angles were made between the 311 keV gamma ray (gated in the movable counter) and 390, 413, 424, 551, and 558 keV gamma rays (displayed in a multichannel analyzer (MCA)). Chance coincidences as well as coincidence background were taken into account. The following spins and mixing ratios were determined: 701 keV level 3/2, δ(390) = 0.19 ± 0.06; 724 keV level 3/2, δ(413) = 0.18 ± 0.05; 735 keV level 5/2, δ(424) = −0.27 ± 0.03; 862 keV level 5/2, δ(551) = −0.28 ± 0.04; 869 keV level 5/2, δ(558) = −0.26 ± 0.05. The result indicates that the anisotropies are consistent with mixing ratios less than 28% in all cases.

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.

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