Coulomb excitation of 35Cl projectiles

1969 ◽  
Vol 47 (10) ◽  
pp. 1065-1075 ◽  
Author(s):  
O. Häusser ◽  
D. Pelte ◽  
T. K. Alexander ◽  
H. C. Evans
Keyword(s):  
Excited States ◽  
Cross Section ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Coulomb Excitation ◽  
Coupling Model ◽  
Absolute Cross Section ◽  
Mixing Ratio ◽  
Lineshape Analysis ◽  
Doppler Shift Attenuation

Coulomb excitation of the first two excited states in 35Cl was studied by bombarding thick foils of 24Mg and carbon with 35Cl ions of energies between 51 and 61 MeV. De-excitation gamma rays were observed in two 40 cm3 Ge(Li) detectors. From absolute cross-section measurements the following B(E2) values were obtained, B(E2, 0 → 1220) = (0.081 ± 0.009) × 10−50 e2 cm4 and B(E2, 0 → 1762) = (1.17 ± 0.09) × 10−50 e2 cm4. The mixing ratio δ(1762 → 0) was measured to be −2.95 ± 0.45 which can be combined with the corresponding B(E2) value to yield τ(1762) = (0.555 ± 0.050) ps. A Doppler shift attenuation method was employed to interpret the observed gamma-ray lineshapes in terms of nuclear lifetimes. The lineshape analysis yielded τ(1220) = (0.16 ± 0.05) ps and confirmed τ(1762) obtained from the absolute cross-section measurements. The results provide evidence that the three lowest states in 35Cl cannot be interpreted by a weak coupling model.

Coulomb excitation of 24Mg with 35Cl ions

1969 ◽  
Vol 47 (18) ◽  
pp. 1929-1940 ◽  
Author(s):  
D. Pelte ◽  
O. Häusser ◽  
T. K. Alexander ◽  
H. C. Evans
Keyword(s):  
Quadrupole Moment ◽  
Cross Section ◽  
Ground State ◽  
State Transition ◽  
Gamma Ray ◽  
Coulomb Excitation ◽  
Absolute Cross Section ◽  
Ground State Transition ◽  
Section Measurement ◽  
Anisotropy Measurement

The Coulomb excitation of a thick 24Mg target was studied with 35Cl ions of 61, 57, and 52 MeV. The absolute cross section and the anisotropy of the angular distribution of the ground state transition from the 1.369-MeV state in 24Mg was measured, and their dependence on B(E2) and the quadrupole moment, Q, of the 1.369-MeV state was calculated. A B(E2) of 24.5 ± 2.2 Weisskopf units (W.u.) was deduced from the line shape of the 1.369-MeV gamma ray observed with a 40 cm3 Ge(Li) detector. The quadrupole moment determined from the anisotropy measurement was Q = −0.38 ± 0.16 b. From the cross-section measurement, Q = −0.47 ± 0.19 b was obtained using B(E2) = 24.5 ± 2.2 W.u. The dependence of this value of Q on B(E2) is discussed.

Absolute Cross Section of the Reaction Cu63(γ, n)Cu62 for Lithium Gamma Rays

1960 ◽  
Vol 15 (11) ◽  
pp. 1913-1919 ◽  
Author(s):  
Shinjiro Yasumi ◽  
Minoru Yata ◽  
Kunio Takamatsu ◽  
Akira Masaike ◽  
Yoshiko Masuda
Keyword(s):  
Cross Section ◽  
Gamma Rays ◽  
Absolute Cross Section

High-Purity Germanium Technology for Gamma-Ray and X-Ray Spectroscopy

1993 ◽  
Vol 302 ◽  
Author(s):  
L.S. Darken ◽  
C. E. Cox
Keyword(s):  
Cross Section ◽  
Gamma Rays ◽  
Ground State ◽  
High Purity ◽  
Gamma Ray ◽  
Capture Rate ◽  
X Rays ◽  
Hole Capture ◽  
High Purity Germanium ◽  
Energy Gamma

ABSTRACTHigh-purity germanium (HPGe) for gamma-ray spectroscopy is a mature technology that continues to evolve. Detector size is continually increasing, allowing efficient detection of higher energy gamma rays and improving the count rate and minimum detectable activity for lower energy gamma rays. For low-energy X rays, entrance window thicknesses have been reduced to where they are comparable to those in Si(Li) detectors. While some limits to HPGe technology are set by intrinsic properties, the frontiers have historically been determined by the level of control over extrinsic properties. The point defects responsible for hole trapping are considered in terms of the “standard level” model for hole capture. This model originates in the observation that the magnitude and temperature dependence of the cross section for hole capture at many acceptors in germanium is exactly that obtained if all incident s-wave holes were captured. That is, the capture rate is apparently limited by the arrival rate of holes that can make an angular-momentum-conserving transition to a s ground state. This model can also be generalized to other materials, where it may serve as an upper limit for direct capture into the ground state for either electrons or holes. The capture cross section for standard levels σS.L. is given bywhere g is the degeneracy of the ground state of the center after capture, divided by the degeneracy before capture. Mc is the number of equivalent extrema in the band structure for the carrier being captured, mo is the electronic mass, m* is the effective mass, and T is the temperature in degrees Kelvin.

The Decay of 169Yb

1972 ◽  
Vol 50 (19) ◽  
pp. 2348-2354 ◽  
Author(s):  
S. K. Sen ◽  
D. L. Salie ◽  
E. Tomchuk
Keyword(s):  
Direct Measurement ◽  
Gamma Rays ◽  
Internal Conversion ◽  
Gamma Ray ◽  
Conversion Coefficient ◽  
Coulomb Excitation ◽  
Internal Conversion Coefficient ◽  
Electron Capture Decay ◽  
Upper Limits ◽  
First Time

The decay of 169Yb was investigated using several Ge(Li) detectors of different sizes. The following gamma rays (energies in keV and intensities within brackets) were definitely identified with the 169Yb decay: 20.7 (0.66 ± 0.04), 63.1 (124 ± 5), 93.6 (7.2 ± 0.3), 109.8 (50 ± 2), 117.3 (0.08 ± 0.04), 118.2 (5.4 ± 0.2), 130.5 (34 ± 2), 156.7 (0.023 ± 0.004), 177.2(59 ± 3), 198.0 (100), 240.4 (0.33 ± 0.02), 261.0 (4.7 ± 0.2), and 307.7 (28 ± 1). The recently reported weak gamma-ray peaks at 515 (0.008 ± 0.002) and 625 (0.010 ± 0.002) were also observed and could not be ruled out as not belonging to 169Yb. The recently reported gamma-ray peaks at 140, 160, 207, 288, 295, 316, 320, 328, 355, 371, 379, 396, and 417 were detected and shown not to be from the decay of 169Yb while those at 218, 229, 285, 304, 335, 388, 411, and 425 were not observed and upper limits were placed on their intensities. The presence of very weak peaks at 515 and 625 establishes the formation of the 633 keV state of 169Tm following electron capture decay of 169Yb as reported by George. (This level has been previously observed only in Coulomb excitation of 169Tm.) The total internal conversion coefficient for the 20.7 keV transition was determined for the first time from the direct measurement of the gamma-ray intensity as 51 ± 10 corresponding to an M1 transition.

scholarly journals Nuclear Structure Investigations of some Medium-Weight Isotopes

2021 ◽  
Author(s):  
◽  
Gavin Wallace
Keyword(s):  
Nuclear Structure ◽  
Beta Decay ◽  
Cross Section ◽  
Gamma Rays ◽  
Half Life ◽  
Decay Scheme ◽  
Gamma Ray ◽  
Calculated Cross Section ◽  
Beta Spectrum ◽  
Gamma Ray Detectors

<p>This thesis describes the methods and results of investigations made to determine the decay schemes of three short-lived isotopes 112Ag, 114Ag and 116Ag. A total of 76 gamma-rays was observed with a Ge(Li) detector in the gamma-radiation which follows the Beta-decay of 112Ag to levels of 112Cd. gamma- gamma coincidence and angular correlation measurements were made with Ge(Li)-NaI(T1) and NaI(T1)-NaI(T1) systems. A decay scheme consistent with the present data is proposed. Cross sections for the reactions 112Cd(n,p)112Ag and 115In(n, alpha)112Ag were measured, and the half-life of the 112Ag decay was found to be 3.14 plus-minus 0.01 hr. The decay scheme of 114Ag was studied with Ge(Li) gamma-ray detectors and plastic Beta-ray detectors. 9 of the 11 gamma-rays observed in the decay were incorporated into 114Cd level structure previously determined by conversion electron measurements on the 113Cd(n,gamma)114Cd reaction. The endpoint energy of the Beta-decay was determined as 4.90 plus-minus 0.26 MeV; no branching was evident in the Beta-spectrum. A decay scheme is proposed for which the Beta-branching was deduced from the measured gamma-ray yield and a calculated cross section value for the 114Cd(n,p)114Ag reaction. The 114Ag half-life was determined as 4.52 plus-minus 0.03 sec; a search for a previously reported isomeric state of 114Ag was unsuccessful. Ge(Li) and NaI(T1) gamma-ray detectors were used to study the direct and coincidence spectra that result from the decay of 116Ag, the half-life of which was found to be 2.50 plus-minus 0.02 min. 53 gamma-rays were observed from this decay. The Beta-branching to the 17 excited states of 116Cd in the proposed decay scheme was derived from the measured gamma-ray yield and a calculated cross section value for the 116Cd(n,p)Ag reaction. Spin and parity assignments for ihe energy levels of 116Cd are made. An investigation of the applicability of two collective models to nuclear structure typical of the Cd nuclei studied demonstrated that one of the models was misleading when applied to vibrational nuclei. A potential function was developed in the other model to extend the investigation to include a study of the transition between extremes of collective motion. This was used to examine the correspondence between nuclear level schemes representative of rotational and vibrational excitations.</p>

Collective States in 151Sm

1971 ◽  
Vol 49 (24) ◽  
pp. 3166-3173 ◽  
Author(s):  
D. E. Nelson ◽  
D. G. Burke ◽  
W. B. Cook ◽  
J. C. Waddington
Keyword(s):  
Strong Coupling ◽  
Gamma Rays ◽  
Cross Sections ◽  
Rotational Band ◽  
Ground State ◽  
Coulomb Excitation ◽  
Coupling Model ◽  
Deuteron Scattering ◽  
Collective States

Inelastic deuteron scattering experiments with a target of 151Sm have been carried out with bombarding energies of 5 MeV and 12 MeV. The scattered deuterons were analyzed with a magnetic spectrograph and B(E2) values for the states populated were extracted from the ratios of inelastic to elastic cross sections. The gamma rays following Coulomb excitation of 151Sm by 50 MeV 35Cl ions were also studied with Ge(Li) detectors. Levels at 65.8 keV, 168.4 keV, and 295.1 keV were populated with B(E2) values of 0.80 e2(barn)2, 0.15 e2(barn)2, and 0.46 e2(barn)2 respectively. If it is assumed that the strong-coupling model is appropriate and that the level at 65.8 keV is the first excited member of a rotational band based on the I = 5/2 ground state, the measured B(E2) value corresponds to a deformation of β = 0.21. It must be noted, however, that the observed states do not satisfy the properties expected for a well-ordered ground-state rotational band.

scholarly journals The absolute cross section of the Fluorescence, Dissociation, and Ionization of H2super excited states

2012 ◽  
Vol 388 (2) ◽  
pp. 022045
Author(s):  
M Glass-Maujean ◽  
Ch Jungen ◽  
H Schmoranzer ◽  
A Knie ◽  
I Haar ◽  
...  
Keyword(s):  
Excited States ◽  
Cross Section ◽  
Absolute Cross Section ◽  
The Absolute

Lifetimes and branching ratios of energy levels of 28Si. I

1969 ◽  
Vol 47 (6) ◽  
pp. 639-649 ◽  
Author(s):  
A. E. Litherland ◽  
P. J. M. Smulders ◽  
T. K. Alexander
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Energy Levels ◽  
Ground Level ◽  
Particle Beam ◽  
High Energy ◽  
Branching Ratios ◽  
Alpha Particles ◽  
Doppler Shift Attenuation ◽  
Energy Gamma

The gamma rays from the 25Mg(α,nγ)28Si reaction have been studied using alpha particles with energies ranging from 4.8 to 6.0 MeV. A 25 cm3 Ge(Li) gamma-ray counter was used to observe the complex high energy gamma-ray spectra at angles between 0° and 130° to the alpha-particle beam. Estimates of the nuclear lifetimes of the energy levels excited were obtained from Doppler shift attenuation measurements. The de-excitation branching ratios of the levels were also measured. The existence of a new level in 28Si at 6695 keV was confirmed. The recently reported 3− level at either 6880 keV or 6889 keV was observed and found to be the 6880-keV member of the doublet. The enhancement of the octupole transition to the ground level of 28Si was found to be 13 Weisskopf units.

Electrical octupole Coulomb excitation in rhodium

1957 ◽  
Vol 239 (1219) ◽  
pp. 487-493 ◽  
Keyword(s):  
Energy Dependence ◽  
Cross Section ◽  
Isomeric State ◽  
Coulomb Excitation ◽  
Absolute Cross Section ◽  
The Absolute ◽  
The Cross ◽  
Octupole Excitation

The electric octupole excitation of the 40 keV isomeric state in 103 Rh has been observed with protons of energies 700 to 1200 keV. The energy dependence of the cross-section is consistent with that predicted by the W. K. B. treatment of Alder & Winther. The absolute cross-section is about three times that expected theoretically. Possible explanations for this discrepancy are suggested.

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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