ANGULAR DISTRIBUTIONS IN GAMMA–ALPHA REACTIONS IN THE NUCLEI OF NUCLEAR EMULSIONS

1965 ◽  
Vol 43 (6) ◽  
pp. 1015-1019 ◽  
Author(s):  
Jan P. Roalsvig
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Ground State ◽  
Intensity Ratio ◽  
Alpha Particles ◽  
Angular Distributions ◽  
Nuclear Emulsions

The angular distribution for alpha particles produced by (γ, α) reactions in the nuclei of nuclear emulsions has been measured. For the reaction 16O(γ, α)12C, in which the 12C nucleus is left in its ground state (J = 0+, T = 0), through an excited state at 12.5 MeV in 16O, the angular distribution is in agreement with a mixture of E1 and E2 interactions, with an E2/E1 intensity ratio of 0.50. For the same reaction, through an excited state at 14.3 MeV in 16O, the angular distribution is best represented by a pure E2 interaction.

Proton?Capture Gamma Rays from Nitrogen?13

1962 ◽  
Vol 15 (3) ◽  
pp. 443 ◽  
Author(s):  
AW Parker ◽  
GG Shute
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Elastic Scattering ◽  
Gamma Rays ◽  
Ground State ◽  
Recent Experiment ◽  
Gamma Ray ◽  
Angular Distributions ◽  
Proton Capture ◽  
Yield Curves

From a recent experiment in this laboratory (Shute et al. 1962) on the elastic scattering of protons from 12C, resonance levels (E13N, J1t) of 13N were obtained at the laboratory bombarding energies (Ep) shown in Table 1. To confirm these results, an investigation of the yield and angular distribution of gamma rays from the reaction 12C(p'YO)13N and 12C(p'Yl)13N was undertaken. Accordingly, the theoretical angular distributions, W(8), for the gamma ray (Yo) to the ground state of 13Na-) and also for the gamma ray (Yl) to the 1st excited state of 13Na+) were evaluated on the assumptions that overlap of levels in 13N is small and lowest order multipoles are involved. As angular distributions are parity insensitive, these were found to be identical for the two gamma rays expected. The simpler of these angular distributions are also shown on the table. The expected angular distributions indicate that 90� is a suitable angle for yield curves.

THE ANGULAR DISTRIBUTION AND YIELD OF THE REACTION F19(p, α0)O16

1957 ◽  
Vol 35 (2) ◽  
pp. 155-167 ◽  
Author(s):  
R. L. Clarke ◽  
E. B. Paul
Keyword(s):  
Angular Distribution ◽  
Least Squares ◽  
Cross Sections ◽  
Legendre Polynomial ◽  
Ground State ◽  
Energy Region ◽  
Alpha Particles ◽  
Angular Distributions ◽  
Method Of Least Squares ◽  
Channel Spin

The yield of the ground state alpha particles from the F19(p, α0)O16 reaction has been studied from an energy of 1.3 Mev. to 2.7 Mev. The observed angular distributions were analyzed in terms of a Legendre polynomial expansion by the method of least squares. Six resonances were found in the energy region studied, at bombarding energies of 1.358 Mev., 1.709 Mev., 1.853 Mev., 2.11 Mev., 2.31 Mev., and 2.58 Mev. The widths and peak cross sections of these resonances are respectively: (54 ± 10 kev., 46 ± 5 mb.), (140 ± 5 kev., 55 ± 6 mb.), (132 ± 5 kev., 77 ± 8 mb.), (75 ± 25 kev., 10 ± 2 mb.), (80 ± 25 kev., 32 ± 5 mb.), and (300 ± 25 kev., 51 ± 10 mb.). Their spins, parities, channel spin mixtures, and partial widths are discussed.

The Surface Loss Correction for Nuclear Emulsions

1951 ◽  
Vol 4 (3) ◽  
pp. 296
Author(s):  
SL Martin
Keyword(s):  
Angular Distribution ◽  
Small Angle ◽  
Small Angle Scattering ◽  
Angular Distributions ◽  
Nuclear Emulsions ◽  
Surface Loss ◽  
Angle Scattering ◽  
Pass Through ◽  
Work Done

When nuclear emulsions are used in the investigation of the angular distributions of scattered particles those tracks which pass through the emulsion surface cannot be accepted for measurement and in consequence the observed angular distribution must be corrected to allow for this. In the present paper, formulae are developed for the case of particles recoiling from a mono-energetic beam of particles incident at any angle on the surface. The effect of small-angle scattering is neglected but on the basis of work done by Powell and Occhialini it is believed that the formulae are valid for recoil energies at least as great as 5 MeV. Curves are given from which the factor can be obtained in any given case.

THE SPIN OF THE 3.70-MEV LEVEL IN Al25

1963 ◽  
Vol 41 (6) ◽  
pp. 923-931 ◽  
Author(s):  
G. J. McCallum
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Band Structure ◽  
Ground State ◽  
Transition Probability ◽  
Spin Assignment ◽  
Mixing Ratio ◽  
Excitation Radiation ◽  
Rotational Bands ◽  
First Excited State

The 3.70-Mev level in Al25 has been studied by means of the reaction Mg24(p, γ)Al25 at the 1.49-Mev resonance. Direct angular distribution measurements of the de-excitation gamma radiation support the spin assignment of 7/2− for this level. An E2/M1 amplitude mixing ratio of −0.55 ± 0.2 is found for the 1.79-Mev de-excitation radiation from the fourth excited state to the ground state of Al25. The ratio of the reduced transition probability of the E2 radiation from the 1.79-Mev level to the first excited state is shown to be ~30 times that to the ground state. This result provides further confirmation of rotational band structure in Al25 since the collective model predicts such an enhancement of E2 transitions between rotational bands whereas cross-band transitions are not expected to be enhanced.

Studies of nuclear collisions involving 8 MeV deuterons by the photographic method - IV. Angular distributions of the particles produced by the bombardment of helium and oxygen

1952 ◽  
Vol 210 (1103) ◽  
pp. 534-543 ◽  
Keyword(s):  
Excited State ◽  
Elastic Scattering ◽  
Experimental Technique ◽  
Ground State ◽  
Angular Distributions ◽  
Photographic Method ◽  
Nuclear Collisions ◽  
Nuclear Processes

An experimental technique described previously has been used to study the angular distributions of the products of nuclear processes occurring when helium and oxygen are bombarded by 8 MeV deuterons. Results on the elastic scattering of deuterons by helium and oxygen nuclei, and on the reactions 4 He ( d,p ) 5 He and 16 O ( d,p ) 17 O, are presented and discussed. The results for the two groups of protons from the latter reaction allow it to be established that the ground state of 17 O has spin 5/2 or 3/2 and even parity, while the 0·88 MeV excited state has spin ½ and even parity.

THE ANGULAR DISTRIBUTION OF GAMMA RAYS IN THE C12(p,p′γ) REACTION

1953 ◽  
Vol 31 (2) ◽  
pp. 189-193 ◽  
Author(s):  
H. E. Gove ◽  
N. S. Wall
Keyword(s):  
Angular Momentum ◽  
Angular Distribution ◽  
Excited State ◽  
Proton Beam ◽  
Gamma Rays ◽  
Ground State ◽  
Expansion Formula ◽  
First Excited State ◽  
Incoming Proton

Protons of 7.1 Mev. energy from the MIT cyclotron have been used to investigate the angular distribution of gamma rays from the C12(p,p′γ) reaction with respect to the incoming proton beam. These gamma rays result from transitions between the first excited state of C12 at 4.45 Mev. and the ground state. The resulting distribution can be fitted by the expansion[Formula: see text]which is consistent with an assignment of two for the angular momentum of the first excited state of C12.

scholarly journals Relative Intensity of the 17·2 and 14·3 MeV Gamma Rays from the 7Li(p,G)8Be Reaction

1960 ◽  
Vol 13 (2) ◽  
pp. 204 ◽  
Author(s):  
B Mainsbridge
Keyword(s):  
Excited State ◽  
Gamma Rays ◽  
Relative Intensity ◽  
Principal Components ◽  
Ground State ◽  
Intensity Ratio ◽  
Proton Capture ◽  
First Excited State

Radiation from proton capture in 7Li is known to consist of two principal components of energy (17�2+~.Ep) and (14'3+~Ep)MeV, corresponding to transitions to the ground state and first excited state of sBe respectively (Walker and McDaniel 1948). Resonances in the reaction are known to exist at Ep=441 keY, 1�03 and 2�1 MeV (Bonner and Evans 1948; Kraus 1954; Price 1954) and the relative intensity of the two y-rays is known to vary in the neighbourhood of the 441 keY resonance (Campbell 1956). It is not known if the intensity ratio varies in the region of the 1030 keY resonance and this experiment was designed to repeat the measurements of Campbell and extend the investigation to the higher resonance.

Neutrons from Deuteron Bombardment of Boron

1957 ◽  
Vol 10 (2) ◽  
pp. 268 ◽  
Author(s):  
JR Bird ◽  
RH Spear
Keyword(s):  
Excited State ◽  
Compound Nucleus ◽  
Ground State ◽  
Angular Distributions ◽  
Particle Model ◽  
Upper Limit ◽  
First Excited State ◽  
Compound Nucleus Formation ◽  
Deuteron Bombardment ◽  
Peak Widths

A natural boron target has been bombarded by 920 keV deuterons, and the emitted neutrons detected using nuclear emulsions. A new procedure for analysing measurements is described ; this procedure allows approximate corrections for errors in geometry in the plane of the emulsions. The dependence of resolution on various experimental factors has been studied, and the resolution achieved is indiCated by peak widths of 245 � 25keV and 360 � 50 keV at neutron energies of 9�7 MeV and 13�9 MeV respectively. The angular distributions of the neutrons from the 10B(d,n)l1C reaction corresponding to the ground state of 11C, and the neutrons from the 11B(d,n)12C reaction corresponding to the 7�66 Me V state in 12C, have been determined; both distributions may be attributed to compound nucleus formation. A search has been made for a neutron group corresponding to an excited state at about 5�5 MeV in 12C suggested by Glassgold and Galonsky (1956) on the basis of the a-particle model. An upper limit for the intensity of any such group is set at 1 per cent. of the intensity of the group corresponding to the first excited state in 12C.

STUDY OF "CONDENSATE" STATES IN 12C AND 16O BY INELASTIC SCATTERING

2008 ◽  
Vol 17 (10) ◽  
pp. 2118-2123 ◽  
Author(s):  
A. S. DEMYANOVA ◽  
A. A. OGLOBLIN ◽  
S. A. GONCHAROV ◽  
T. L. BELYAEVA
Keyword(s):  
Inelastic Scattering ◽  
Excited States ◽  
Ground State ◽  
Transfer Reaction ◽  
Alpha Particles ◽  
Angular Distributions ◽  
Hoyle State

Study of some properties of the lowest states of 12 C , including the second 0+, 7.65 MeV (Hoyle) state by inelastic scattering of alpha-particles and 3 He were carried out. Two independent methods of measuring the radii of the short-lived excited states based on the analysis of diffraction and rainbow patterns of the angular distributions were proposed. Both methods showed that Hoyle state radius is by factor ~ 1.2 – 1.3 larger than that of the ground state. 8 Be transfer reaction was identified. The probability of L = 0 configuration in Hoyle state occurred to be 3 times larger than in the ground state indicating to the significant presence of condensate configuration in the former one.

Positive-Parity Bands in 29Si

1971 ◽  
Vol 49 (10) ◽  
pp. 1263-1274 ◽  
Author(s):  
A. A. Pilt ◽  
R. H. Spear ◽  
R. V. Elliott ◽  
J. A. Kuehner
Keyword(s):  
Angular Distribution ◽  
Excited State ◽  
Linear Polarization ◽  
Ground State ◽  
Gamma Ray ◽  
Positive Parity ◽  
Rotational Bands ◽  
Mixing Ratios ◽  
First Excited State ◽  
Nilsson Model

A study has been made of several high spin members of the ground state (Kπ = 1/2+) and first-excited state (Kπ = 3/2+) rotational bands in the presumed oblate nucleus 29Si. Gamma-ray angular distribution and linear polarization measurements have confirmed the spin and parity of the 4081 keV level to be 7/2+, and levels at 4742 and 5283 keV have been shown to have Jπ = 9/2+ and (7/2+, 3/2+) respectively. Branching and mixing ratios for the transitions from these states have also been determined; in conjunction with previously measured lifetimes, transition strengths are calculated. The results are compared with the predictions of a Nilsson-model calculation including the effects of coriolis mixing of the low-lying positive parity bands.

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