THE EFFECT OF INTERACTIONS ON THE ANGULAR DISTRIBUTION OF γ-RAYS FROM AN ASSEMBLY OF ORIENTED NUCLEI

1957 ◽  
Vol 35 (9) ◽  
pp. 1133-1145 ◽  
Author(s):  
J. M. Daniels
Keyword(s):  
Angular Distribution ◽  
Energy State ◽  
Nuclear Orientation ◽  
Γ Radiation ◽  
Orientation Experiment ◽  
High Temperature Approximation ◽  
Γ Rays ◽  
Matrix Formula ◽  
Paramagnetic Ions ◽  
Radioactive Ions

The angular distribution of γ-radiation from an assembly of nuclei oriented by the magnetic h.f.s. method can be very much modified by interactions between the radioactive ions and other paramagnetic ions in the crystal. In order to calculate the effect of these interactions, an operator Γ is derived which represents the angular distribution of γ-rays from a radioactive nucleus. The angular distribution at any temperature is given by Spur(Γρ), where ρ is the statistical matrix [Formula: see text], [Formula: see text] being the Hamiltonian for the whole crystal. For a high temperature approximation, ρ is expanded in powers of 1/T. It is found that, for alignment by the magnetic h.f.s. method, the first term which contains interaction parameters is that in 1/T4, and an expression is given for the contribution of interactions to this term.At very low temperatures, perturbation theory is used to estimate the effect of interactions on the lowest nuclear energy state, and hence on the angular distribution of γ-rays. It is found that, if an external magnetic field is applied along a principal axis of the g-tensor of the radioactive ions, interactions have no influence on the angular distribution of γ-rays in the limit of large fields. It is also shown that Bleaney's restriction, that for a successful nuclear orientation experiment the broadening of the levels should be less than the hyperfine splitting, is not necessary in this case.

Nuclear orientation facility for the study of the angular distribution of γ radiation and β particles emitted by polarized nuclei

1984 ◽  
Vol 219 (1) ◽  
pp. 103-110 ◽  
Author(s):  
Leo M. Chirovsky ◽  
Wen-Piao Lee ◽  
Albert M. Sabbas ◽  
Arthur J. Becker ◽  
Joel L. Groves ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Nuclear Orientation ◽  
Γ Radiation

Nuclear alinement of manganese-56

1959 ◽  
Vol 250 (1263) ◽  
pp. 550-561 ◽  
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Angular Correlation ◽  
Excited States ◽  
Daughter Nucleus ◽  
Γ Radiation ◽  
Mixing Ratios ◽  
First Excited State ◽  
Γ Rays ◽  
Coincidence Measurements

The present work demonstrates the feasibility of alining manganese-56 produced by neutron irradiation of a nickel fluosilicate crystal containing stable 55 Mn. Measurements were made of the angular distribution of the γ-radiation from the alined 56 Mn and also of the angular correlation of the γ-rays from this isotope. By combining the results it is possible to establish uniquely as 2 the spins of the states of the daughter nucleus of 56 Fe at 2.66 and 2.98 MeV. The mixing ratios δ ( E 2/ M 1) for the 1.81 and 2.13 MeV γ-rays to the first excited state are shown to be 0.19 ± 0.02 and — 0.28 ± 0.02. The spectrum of the γ-radiation was studied with a scintillation spectrometer and this leads to the following relative intensities; 0.845 MeV (100%), 1.81 MeV (27 ± 3%), 2.13 MeV (15 ± 3%), 2.55 MeV (1.2 ± 0.2%), 2.66 MeV (0.65 ± 0.1%), 2.98 MeV (0.35 ± 0.1%) and 3.4 MeV (0.22 ± 0.05%). Coincidence measurements suggest that the 2.55 and 3.4 MeV γ-rays are due to de-excitation of a level at about 3.4 MeV which decays both to the ground and first excited states. A spin of 2 for this state is proposed.

scholarly journals Monte Carlo Simulation of γ − γ Correlation Functions

Atoms ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 6
Author(s):  
Mohamed Omer ◽  
Mahmoud Bakr
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Angular Distribution ◽  
Correlation Functions ◽  
Energy State ◽  
Nuclear Resonance ◽  
Resonance Fluorescence ◽  
Spin Parity ◽  
Nuclear Resonance Fluorescence ◽  
Γ Rays

γ − γ correlation functions are mathematical expressions that describe the angular distribution of cascade γ -rays emitted from an atomic nucleus. Cascade transitions may occur in either a two-step deexcitation or through an excitation-deexcitation process of a particular energy level inside the nucleus. In both cases, the nucleus returns to its ground energy state. Spin and parity of the excited state can be determined experimentally using the asymmetry of the angular distribution of the emitted radiation. γ − γ correlation functions are only valid for point-like targets and detectors. In the real experiments, however, neither the target nor the detector is point-like. Thus, misassignment of the spin-parity of energy levels may easily take place if only the analytical equations are considered. Here, we develop a new Monte Carlo simulation method of the γ − γ correlation functions to account for the extended target and detector involved in spin-parity measurements using nuclear resonance fluorescence of nuclei. The proposed simulation tool can handle arbitrary geometries and spin sequences. Additionally, we provide numerical calculations of a parametric study on the influence of the detection geometry on the angular distribution of the emitted γ -rays. Finally, we benchmark our simulation by comparing the simulation-estimated asymmetry ratios with those measured experimentally. The present simulation can be employed as a kernel of an implementation that simulates the nuclear resonance fluorescence process.

ALPHA DECAY AND FISSION OF ALIGNED NUCLEI

1960 ◽  
Vol 38 (2) ◽  
pp. 290-314 ◽  
Author(s):  
N. R. Steenberg ◽  
R. C. Sharma
Keyword(s):  
Angular Distribution ◽  
High Temperature ◽  
Experimental Work ◽  
Low Temperatures ◽  
Alpha Decay ◽  
Alpha Particles ◽  
Nuclear Shape ◽  
Fission Fragments ◽  
Partial Waves ◽  
High Temperature Approximation

The theory of the angular distribution of alpha particles and of fission fragments from nuclei aligned at low temperatures is presented. Very explicit results are obtained in the high temperature approximation. These are directly dependent upon the branching which takes place to the various allowed partial waves. This branching is influenced by the nuclear shape, but it is shown that for this problem the effect of penetrating a spheroidal barrier is not critical. An application is made to the experimental work so far available and the result is reasonably satisfactory.

scholarly journals Measurement of the angular distribution of γ-rays emitted from the compound state after neutron capture by 81Br for a search of T-violation

2019 ◽  
Vol 219 ◽  
pp. 09003 ◽  
Author(s):  
Shunsuke Endo ◽  
Hirohiko M. Shimizu ◽  
Masaaki Kitaguchi ◽  
Hirota Katsuya ◽  
Tomoki Yamamoto ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Parity Violation ◽  
Neutron Capture ◽  
P Waves ◽  
Compound State ◽  
T Violation ◽  
Reversal Invariance ◽  
Candidate Target ◽  
First Results ◽  
Γ Rays

It is known that parity violation can be enhanced in compound nuclei due to mixing of s- and p-waves, and it is suggested that time reversal invariance (T) violation is enhanced by the same mechanism. We are planing a T-violation search using compound nuclei produced in neutron capture reactions. Although 81Br is one of the candidate target nuclei, its sensitivity to T-violation has not yet been determined. For an estimate of the latter, a measurement of the angular distribution of γ-rays emitted in the 81Br(n,γ) reaction was carried out in November 2017, of which we report first results.

NUCLEAR ORIENTATION IN ANTIFERROMAGNETIC SINGLE CRYSTALS

1961 ◽  
Vol 39 (1) ◽  
pp. 53-64 ◽  
Author(s):  
J. M. Daniels ◽  
J. C. Giles ◽  
M. A. R. LeBlanc
Keyword(s):  
Single Crystals ◽  
Nuclear Orientation ◽  
Γ Rays ◽  
Γ Ray

Mn54 and Co60 have been successfully oriented in five antiferromagnetic single crystals (MnCl2∙4H2O, MnBr2∙4H2O, CoCl2∙6H2O, Co(NH4)2(SO4)2∙ 6H2O, and MnSiF6∙6H2O) and the orientation was detected by the anisotropy of the emitted γ rays. Only in the case of Co60 in MnBr2∙4H2O was no γ-ray anisotropy seen. It is concluded that antiferromagnetism can be used as a means of producing nuclear orientation. Attempts to orient Br82 and 1131 in the manganese halides by superexchange were unsuccessful.

scholarly journals The excitation of γ-radiation in processes of proton capture

1939 ◽  
Vol 172 (948) ◽  
pp. 72-89 ◽  
Keyword(s):  
High Energy ◽  
Light Elements ◽  
Proton Capture ◽  
Energy Excitation ◽  
Γ Radiation ◽  
Quantum Energy ◽  
Sodium Magnesium ◽  
Five Elements ◽  
Γ Rays ◽  
Resonance Character

1. Introduction It is found th at many light elements emit γ-radiation during bombardment by protons of high energy. Excitation curves relating the intensity of the emitted γ-radiation with the energy of the incident protons do not increase smoothly with increasing bombarding voltage, but show, in most instances, pronounced maxima. The resonance character of these excitation curves is most naturally explained by assuming that the γ-radiations arise in the process of capture of protons by nuclei, and measurements of the quantum energies of these radiations lend general support to the assumption that the γ-rays have this origin. In a previous paper (Curran, Dee and Petrzilka 1938) the results of an investigation of the process of proton capture by the four light elements, beryllium, boron, carbon and fluorine, have been given. The experiments have now been extended to include the five elements lithium, sodium, magnesium, phosphorus and chlorine. The form of the excitation curve for the intensity of the capture γ-radiation has been determined for incident protons of energy up to 10 6 eV, and in each case the quantum energy of the radiation has been measured. An attem pt has also been made to detect the capture of protons by deuterium but no definite evidence of the occurrence of this process could be obtained.

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