Lifetimes of Low Lying Levels of 18O, 18Ne

1974 ◽  
Vol 52 (15) ◽  
pp. 1381-1388 ◽  
Author(s):  
A. B. McDonald ◽  
T. K. Alexander ◽  
O. Häusser ◽  
G. J. Costa ◽  
J. S. Forster ◽  
...  
Keyword(s):  
Doppler Shift ◽  
Transition Rates ◽  
Distance Method ◽  
Doppler Shift Attenuation ◽  
Theoretical Predictions ◽  
Γ Rays ◽  
Recoil Distance

The T(16O,p)18O reaction has been employed to measure the lifetimes of the 1.98 MeV 2+ level (τ = 3.35 ± 0.20 ps) and the 3.55 MeV 4+ level (τ = 24.5 ± 3.3 ps) of 18O by the recoil distance method. The lifetime of the 1.89 MeV 2+ level of 18Ne (τ = 0.63 ± 0.13 ps) has been measured by observing the Doppler shift attenuation of γ rays from 18Ne ions recoiling from the 16O(3He,n) reaction into Y and Ta backings. Transition rates in these mirror nuclei are compared with theoretical predictions.

Lifetimes of States in 29Si, 27Al, and 26Mg

1971 ◽  
Vol 49 (23) ◽  
pp. 2886-2897 ◽  
Author(s):  
A. B. McDonald ◽  
T. K. Alexander ◽  
O. Häusser ◽  
G. T. Ewan
Keyword(s):  
Doppler Shift ◽  
Line Shape ◽  
Coulomb Excitation ◽  
Thick Target ◽  
Distance Method ◽  
Model Predictions ◽  
Doppler Shift Attenuation ◽  
Recoil Distance ◽  
Doppler Shift Attenuation Method

The recoil-distance method was used to measure the lifetimes of the 29Si, 3626 keV (7/2−) level (4.2 ± 0.5 ps) from the 12C(19F,npγ)29Si reaction, the 26Mg, 1809 keV (2+) level (0.7 ± 0.3 ps) from the 12C-(19F,αpγ)26Mg reaction, and the 27Al, 843 keV (1/2+) level (45 ± 6 ps) from the 27Al(35Cl,35Cl)27Al Coulomb excitation reaction. The Doppler shift attenuation method was employed to determine the lifetime of the 27Al, 1013 keV (5/2+) level [Formula: see text] from the line shape for thick target Coulomb excitation by 67 MeV 35Cl. The results are compared with model predictions.

Consistency of the recoil-distance method and the Doppler-shift attenuation method for lifetime measurements using titanium as the slowing-down environment

1975 ◽  
Vol 11 (1) ◽  
pp. 280-281 ◽  
Author(s):  
B. Haas ◽  
J. Chevallier ◽  
N. Schulz ◽  
J. Styczen ◽  
M. Toulemonde
Keyword(s):  
Doppler Shift ◽  
Distance Method ◽  
Lifetime Measurements ◽  
Slowing Down ◽  
Doppler Shift Attenuation ◽  
Recoil Distance ◽  
Doppler Shift Attenuation Method

Lifetime measurements of the six lowest lying levels in 35Cl

1969 ◽  
Vol 47 (12) ◽  
pp. 1295-1306 ◽  
Author(s):  
F. Ingebretsen ◽  
T. K. Alexander ◽  
O. Häusser ◽  
D. Pelte
Keyword(s):  
Gamma Rays ◽  
Doppler Shift ◽  
Gamma Ray ◽  
Level Structure ◽  
Branching Ratios ◽  
Distance Method ◽  
Lifetime Measurements ◽  
Mixing Ratios ◽  
Doppler Shift Attenuation ◽  
Recoil Distance

The energies, gamma-ray branching ratios, and mean nuclear lifetimes of the six lowest lying levels in 35Cl have been measured. Gamma rays following the reaction 32S(α,pγ)35Cl were studied using two Ge(Li) detectors with 15-cm3 and 40-cm3 active volumes respectively. The lifetimes of the five lowest lying levels were measured using the Doppler shift attenuation method, with the results: 1219 keV, [Formula: see text]; 1763 keV, 0.55 ± 0.15 ps; 2646 keV, 0.30 ± 0.09 ps; 2695 keV, <0.03 ps; and 3003 keV, <0.05 ps. The lifetime of the 3163-keV level was measured to be 60 ± 7 ps, using a recoil distance method. The level structure is discussed taking into account known lifetimes, spins, parities, and gamma-ray mixing ratios.

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.

EVIDENCE FOR X(5) CRITICAL POINT SYMMETRY IN 128Ce

2006 ◽  
Vol 15 (08) ◽  
pp. 1735-1740 ◽  
Author(s):  
D. L. BALABANSKI ◽  
K. A. GLADNISHKI ◽  
G. LO BIANCO ◽  
A. SALTARELLI ◽  
N. V. ZAMFIR ◽  
...  
Keyword(s):  
Critical Point ◽  
Nuclear Structure ◽  
Excited States ◽  
Ground State ◽  
Doppler Shift ◽  
Point Symmetry ◽  
Yale University ◽  
Doppler Shift Attenuation ◽  
Recoil Distance ◽  
Predicted Values

Lifetimes of excited states in 128 Ce were measured using the recoil distance Doppler-shift (RDDS) and the Doppler-shift attenuation (DSAM) methods. The experiments were performed at the Wright Nuclear Structure Laboratory of Yale University. Excited states of 128 Ce were populated in the 100 Mo (32 Si ,4 n ) reaction at 120 MeV and the nuclear γ decay was measured with an array of eight Clover detectors positioned at forward and backward angles. The deduced yrast transition strengths together with the energies of the levels within the ground-state (gs) band of 128 Ce are in agreement with the predicted values for the X (5) critical point symmetry. Thus, we suggest 128 Ce as a benchmark X (5) nucleus in the mass A ≈ 130 region.

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.

LIFETIME MEASUREMENTS IN 134Pr AND CHIRALITY IN NUCLEI

2006 ◽  
Vol 15 (07) ◽  
pp. 1531-1540 ◽  
Author(s):  
D. TONEV ◽  
P. PETKOV ◽  
D. L. BALABANSKI ◽  
G. DE ANGELIS ◽  
A. GADEA ◽  
...  
Keyword(s):  
Doppler Shift ◽  
Transition Probabilities ◽  
Experimental Results ◽  
Lifetime Measurements ◽  
Evaporation Reaction ◽  
Doppler Shift Attenuation ◽  
Recoil Distance ◽  
Reduced Transition Probabilities ◽  
Fusion Evaporation Reaction

Lifetimes of exited states in 134 Pr were measured be means of the recoil distance Doppler-shift and Doppler-shift attenuation techniques. The experiments were performed at IReS, Strasbourg using the EUROBALL IV spectrometer, in conjunction with the inner BGO ball and the Cologne coincidence plunger apparatus. Exited states in 134 Pr were populated in the fusion-evaporation reaction 119 Sn (19 F , 4 n )134 Pr . Reduced transition probabilities in 134 Pr are compared to the predictions of the two quasiparticle+triaxial rotor and interacting boson fermion-fermion models. The experimental results do not support the presence of static chirality in 134 Pr underlying the importance of shape fluctuations. Only within a dynamical context the presence of intrinsic chirality in 134 Pr can be supported.

An examination of Doppler shift attenuation factors and lifetimes for excited nuclear states in 59Cu and 63Cu

1980 ◽  
Vol 58 (3) ◽  
pp. 359-362 ◽  
Author(s):  
B. E. Cooke ◽  
J. R. Leslie ◽  
W. McLatchie ◽  
P. Skensved
Keyword(s):  
Energy Loss ◽  
Excited States ◽  
Doppler Shift ◽  
Speed Of Light ◽  
Proton Capture ◽  
Doppler Shift Attenuation ◽  
Resonance Strengths ◽  
Γ Rays ◽  
Standard Energy ◽  
Existing Data

Excited states in 59Cu and 63Cu have been studied with radiative proton capture. Doppler shift attenuation factors have been measured for γ-rays depopulating these states, with ion recoil speeds of approximately 0.1% of the speed of light. Measurements of resonance strengths reported here, together with existing data from other techniques, have been used to deduce lifetimes for the same states. For five cases where the DSA factors and the lifetimes have been determined independently, consistency with DSAM theory is optimized when the standard energy loss value is multiplied by a factor of 0.94 ± 0.11.

Mesures de Rapports d'Embranchement et de Vies Moyennes dans 30Si

1972 ◽  
Vol 50 (3) ◽  
pp. 278-286 ◽  
Author(s):  
A. Gallmann ◽  
F. Haas ◽  
M. Toulemonde
Keyword(s):  
Shell Model ◽  
Gamma Rays ◽  
Doppler Shift ◽  
Branching Ratios ◽  
Matrix Elements ◽  
Excitation Energies ◽  
Doppler Shift Attenuation ◽  
Annular Detector ◽  
Γ Rays

Gamma rays from the decay of 30Si levels with excitation energies less than 6.0 MeV have been studied by the 27Al(α, pγ)30Si reaction. The γ rays were detected in a Ge(Li) detector in coincidence with protons observed in an annular detector placed at 180°. Branching ratios and lifetimes have been extracted. The lifetimes have been measured by the Doppler-shift attenuation method.The electromagnetic matrix elements for some of the observed levels were compared with recent many-particle shell model and core-coupling calculations.

scholarly journals Some Doppler-shift lifetimes in 30P

1970 ◽  
Vol 48 (19) ◽  
pp. 2336-2339 ◽  
Author(s):  
A. Lachaine ◽  
B. Hird
Keyword(s):  
Doppler Shift ◽  
Doppler Shift Attenuation ◽  
Γ Rays ◽  
Doppler Shift Attenuation Method

The Doppler-shift attenuation method has been used to determine some lifetimes in 30P which are populated by the decay of resonances in the 29Si(p,γ)30P reaction at 1505, 1643, and 1686 keV, and the 1773–5 keV doublet. There is evidence that either the 1775 keV component of the doublet has a measurable lifetime of 10 ± 5 fs or that all the observed radiation from this doublet contains γ rays from both components.

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