STUDIES IN THE DECAY OF THE ACTIVE DEPOSIT OF ACTINIUM: I. ALPHA–GAMMA ANGULAR CORRELATION IN THE DECAY OF Bi211 (AcC)

1964 ◽  
Vol 42 (9) ◽  
pp. 1798-1812 ◽  
Author(s):  
C. R. Cothern ◽  
R. D. Connor
Keyword(s):  
Shell Model ◽  
Angular Correlation ◽  
Angular Momenta ◽  
Mixing Parameters ◽  
Isotropic Distribution ◽  
Model Predictions ◽  
Γ Ray ◽  
Polarization Correlation ◽  
Do So ◽  
Isotropy Condition

The α–γ angular correlation of the cascade Bi211(α, 6.27 MeV)Tl207*(γ, 350 keV)Tl207 has been found to be isotropic to within [Formula: see text].Accepting the spin and parity of the ground state of Tl207as 1/2+, a search was made for all reasonable spins and angular momenta, pure and mixed, which could yield an isotropic correlation. Shell-model predictions and other situations have been examined. No case of unmixed α-, unmixed γ-angular momenta satisfies the isotropy condition. Many other cases are found which do so, but only with the spin and parity of the excited state of Tl207 taken as 3/2+. It has been shown that 5/2+ does not yield an isotropic correlation. With one radiation mixed and the other pure, there are eight possible combinations which fit the observations. With both radiations mixed, there is an infinity of combinations of the two mixing parameters which lead to an isotropic distribution. The αk value of the 350-keV transition (0.175 ± 0.017) shows the γ ray in question to be 76% M1 and 24% E2. The present work is consistent with only one of the two possibilities given by Gorodetzky et al. (1962) from polarization–correlation work. Accepting this additional evidence it would appear that the most plausible interpretation is that of shell-model spins and parities with both radiations mixed, α—(λ = 3, 5), γ—(76% M1, 24% E2).

scholarly journals Partial conservation law in a schematic single j shell model

2017 ◽  
Vol 26 (01n02) ◽  
pp. 1740021 ◽  
Author(s):  
Wesley Pereira ◽  
Ricardo Garcia ◽  
Larry Zamick ◽  
Alberto Escuderos ◽  
Kai Neergård
Keyword(s):  
Angular Momentum ◽  
Matrix Element ◽  
Shell Model ◽  
Linear Function ◽  
Conservation Law ◽  
Interaction Matrix ◽  
Stationary States ◽  
Interaction Matrix Element ◽  
Angular Momenta ◽  
Partial Conservation

We report the discovery of a partial conservation law obeyed by a schematic Hamiltonian of two protons and two neutrons in a [Formula: see text] shell. In our Hamiltonian, the interaction matrix element of two nucleons with combined angular momentum [Formula: see text] is linear in [Formula: see text] for even [Formula: see text] and constant for odd [Formula: see text]. It turns out that in some stationary states, the sum of the angular momenta [Formula: see text] and [Formula: see text] of the proton and neutron pairs is conserved. The energies of these states are given by a linear function of [Formula: see text]. The systematics of their occurrence is described and explained.

MUTAGENESIS IN CAENORHABDITIS ELEGANS. II. A SPECTRUM OF MUTATIONAL EVENTS INDUCED WITH 1500 R OF γ-RADIATION

Genetics ◽  
1985 ◽  
Vol 109 (3) ◽  
pp. 493-511
Author(s):  
Raja E Rosenbluth ◽  
Cheryl Cuddeford ◽  
David L Baillie
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Chromosomal Rearrangements ◽  
Γ Radiation ◽  
Recessive Lethal ◽  
C Elegans ◽  
Chromosome Breaks ◽  
Additional Chromosome ◽  
Γ Ray ◽  
Do So

ABSTRACT We previously established a γ-ray dose-response curve for recessive lethal events (lethals) captured over the eT1 balancer. In this paper we analyze the nature of lethal events produced, with a frequency of 0.04 per eT1 region, at a dose of 1500 r. To do so, we developed a protocol that, in the absence of cytogenetics, allows balanced lethals to be analyzed for associated chromosomal rearrangements. A set of 35 lethal strains was chosen for the analysis. Although the dosage was relatively low, a large number of multiple-break events were observed. The fraction of lethals associated with rearrangements was found to be 0.76. Currently most X- and γ-ray dosages used for mutagenesis in C. elegans are 6000-8000 r. From our data we conservatively estimated that 43% of rearrangements induced with 8000 r would be accompanied by additional chromosome breaks in the genome. With 1500 r the value was 5%.—The 35 lethals studied were derived from 875 screened F1's. Among these lethals there were (1) at least two unc-36 duplications, (2) at least four translocations, (3) at least six deficiencies of chromosome V (these delete about 90% of the unc-60 to unc-42 region) and (4) several unanalyzed rearrangements. Thus, it is possible to recover desired rearrangements at reasonable rates with a dose of only 1500 r.—We suggest that the levels of ionizing radiation employed in most published C. elegans studies are excessive and efforts should be made to use reduced levels in the future.

Perturbation of γ-ray angular correlation by an Ornstein-Ulhenbeck process

1992 ◽  
Vol 45 (9) ◽  
pp. 4745-4751 ◽  
Author(s):  
A. K. Dhara ◽  
S. K. Das
Keyword(s):  
Angular Correlation ◽  
Γ Ray

FIRST γ-RAY SPECTROSCOPY AND ISOSPIN SYMMETRY STUDY OF THE N = Z - 2 NUCLEUS 44V

2010 ◽  
Vol 25 (21n23) ◽  
pp. 2028-2029 ◽  
Author(s):  
M. J. TAYLOR ◽  
M. A. BENTLEY ◽  
J. BROWN ◽  
R. WADSWORTH ◽  
P.E. KENT ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Shell Model ◽  
Excited States ◽  
State Of The Art ◽  
Isospin Symmetry ◽  
Charge Symmetry Breaking ◽  
Charge Symmetry ◽  
Model Calculations ◽  
Γ Ray ◽  
First Time

Excited states in the Tz = -1 nucleus 44 V have been observed for the first time. The states have been identified through recoil-γ-γ coincidences and comparison with analogue states in the mirror nucleus 44 Sc . Mirror energy differences have been extracted and compared to state-of-the-art fp shell-model calculations which include charge symmetry breaking forces.

Spectroscopic Study of 32S Through the 31P(d,n)32S Reaction

1974 ◽  
Vol 52 (14) ◽  
pp. 1288-1294 ◽  
Author(s):  
A. H. Hussein ◽  
G. C. Neilson ◽  
W. J. McDonald ◽  
W. K. Dawson
Keyword(s):  
Spectroscopic Study ◽  
Shell Model ◽  
Cross Sections ◽  
Differential Cross ◽  
Time Of Flight ◽  
Angular Distributions ◽  
Absolute Differential ◽  
Spectroscopic Factors ◽  
Model Predictions ◽  
Theoretical Predictions

The 31P(d,n)32S reaction has been studied at deuteron energies of 4.0 and 5.45 MeV. Neutron energies were measured by time of flight. Absolute differential cross sections of seven levels in 32S have been measured and compared with the theoretical predictions of both the DWBA and compound statistical theories. Analysis of the angular distributions yielded lP values and absolute spectroscopic factors. These results have been compared with those from other experiments and shell model predictions.

scholarly journals MACROSCOPIC-MICROSCOPIC ENERGY OF ROTATING NUCLEI IN THE FUSION-LIKE DEFORMATION VALLEY

2000 ◽  
Vol 09 (01) ◽  
pp. 51-66 ◽  
Author(s):  
RADU A. GHERGHESCU ◽  
GUY ROYER
Keyword(s):  
Shell Model ◽  
Liquid Drop ◽  
Fission Barrier ◽  
Liquid Drop Model ◽  
Potential Barriers ◽  
Angular Momenta ◽  
Microscopic Origin ◽  
Microscopic Energy ◽  
Rotating Nuclei

The energy of rotating nuclei in the fusion-like deformation valley has been determined within a liquid drop model including the proximity energy, the two-center shell model and the Strutinsky method. The potential barriers of the 84 Zr , 132 Ce , 152 Dy and 192 Hg nuclei have been determined. A first minimum having a microscopic origin and lodging the normally deformed states disappears with increasing angular momenta. The microscopic and macroscopic energies contribute to generate a second minimum where superdeformed states may survive. It becomes progressively the lowest one at intermediate spins. At higher angular momenta, the minimum moves towards the foot of the external fission barrier leading to hyperdeformed quasi-molecular states.

Shell-model predictions for electromagnetic properties ofN=50nuclei

1988 ◽  
Vol 38 (6) ◽  
pp. 2849-2859 ◽  
Author(s):  
Xiangdong Ji ◽  
B. H. Wildenthal
Keyword(s):  
Shell Model ◽  
Electromagnetic Properties ◽  
Model Predictions

scholarly journals Probing Density Fluctuations in the Universe with the FIRST Radio Survey

1999 ◽  
Vol 183 ◽  
pp. 244-244
Author(s):  
C.M. Cress
Keyword(s):  
Correlation Function ◽  
Power Spectrum ◽  
Angular Correlation ◽  
Density Fluctuations ◽  
Linear Evolution ◽  
Angle Measurements ◽  
Model Predictions ◽  
Non Linear ◽  
Angular Correlation Function ◽  
The Universe

We compare the angular correlation function measured for FIRST sources (Becker et al., Cress et al.) with COBE-normalized CDM-model predictions (Cress & Kamionkowski). We note that uncertainties in the z-distribution do not affect the predictions dramatically and that the effects of non-linear evolution of the power spectrum are significant for θ<∼20′. We find the CF at larger angles to be sensitive to clustering of nearby sources. The smaller angle measurements, when combined with results from other surveys (Loan et al., Rengelink et al.) indicate that the bias required for the data to fit CDM models increases as the surveys probe deeper. We also point the reader to Refregier et al. for information on the use of weak lensing of FIRST sources in probing foreground mass.

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