Angular Distribution of α-Particles from the Li7 (p,α) He4 Reaction

1949 ◽  
Vol 2 (1) ◽  
pp. 25 ◽  
Author(s):  
LH Martin ◽  
JC Bower ◽  
DNF Dunbar ◽  
F Hirst
Keyword(s):  
Angular Distribution ◽  
Nuclear Reaction ◽  
Proton Energy ◽  
Electrostatic Generator ◽  
The Asymmetry ◽  
Ancillary Equipment ◽  
Α Particles

A description is given of a 1 MV, electrostatic generator and ancillary equipment which has been used to study the asymmetry in the angular distribution of α-particles from the Li7 (p, α) He4 reaction. The angular distribution of the a-particles is given by the expression Y(θ) =Y(90�)[1 +A(E) cos2θ + B(E)cos4 θ] where A(E) and B(E) are functions of the proton energy. The form of the expression implies the existence of both p and f protons in the nuclear reaction.

The transformation of the nitrogen isotope of mass 15 into carbon and helium by bombardment with protons

1949 ◽  
Vol 199 (1059) ◽  
pp. 458-468 ◽  
Keyword(s):  
Angular Distribution ◽  
Nuclear Reaction ◽  
Cross Section ◽  
Nitrogen Isotope ◽  
Photographic Method ◽  
The Sun ◽  
Broad Maximum ◽  
Dispersion Formula ◽  
The One ◽  
Α Particles

Measurements of the ‘cross-section’ of the nuclear reaction N 15 (p, α) C 12 have been made for protons with different values of the energy in the interval between 200 and 450 keV. There are indications of a broad maximum, in the curve showing the variation of ‘cross-section’ with energy, in the neighbourhood of 400 keV, with a width of 150 keV. The partial proton width of the maximum is 250 eV. Extrapolation of the one-level dispersion formula, together with the theory of thermonuclear reactions, gives a lifetime of 3 x 10 4 years for N 15 in the sun. A photographic method of determining the angular distribution of the emitted α-particles is described. The angular distribution near 400 keV is found to be approximately isotropic, the deviations from isotropy being, at most, 10%.

Study of the 1459-keV level in 19F by the 19F(p,p′γ)19F reaction

1970 ◽  
Vol 48 (7) ◽  
pp. 827-833 ◽  
Author(s):  
S. T. Lam ◽  
A. E. Litherland ◽  
J. J. Simpson
Keyword(s):  
Angular Distribution ◽  
Single Crystal ◽  
Linear Polarization ◽  
Proton Energy ◽  
Branching Ratios ◽  
Mixing Ratio ◽  
Γ Ray ◽  
Good Agreement

The 1459-keV level of 19F was populated by the 19F(p,p′γ)19F reaction at a proton energy of 2.78 MeV. The E2/M1 mixing ratio for the 1459 → 110 keV transition was determined to be [Formula: see text] from a combination of the γ-ray angular distribution and linear polarization and the nuclear lifetime. The γ-ray angular distribution was measured with a coaxial Ge(Li) detector and the γ-ray linear polarization with a planar Ge(Li) detector. The corresponding E2 and M1 transition strengths for a lifetime of 0.084 ± 0.020 ps are found to be [Formula: see text] and 0.10 ± 0.03 W.u. respectively. They are in good agreement with the particle–hole calculations of Benson and Flowers. The branching ratios of the 1459-keV level agree well with those of Poletti et al. The γ-ray transitions from the 1459-keV level provide a good example for demonstrating the usefulness of a single crystal Ge(Li) polarimeter.

Proton angular distribution research by a new angle-resolved proton energy spectrometer

2014 ◽  
Vol 57 (5) ◽  
pp. 844-848 ◽  
Author(s):  
LuNing Su ◽  
Yi Zheng ◽  
Meng Liu ◽  
ZhiDan Hu ◽  
WeiMin Wang ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Proton Energy ◽  
Energy Spectrometer

A precise technique for the determination of some nuclear reaction energies

1953 ◽  
Vol 216 (1125) ◽  
pp. 219-241 ◽  
Keyword(s):  
Nuclear Reaction ◽  
Empirical Method ◽  
Effective Diameter ◽  
Line Shapes ◽  
Standard Scale ◽  
Theoretical Line ◽  
Reaction Energies ◽  
The Magnetic Field ◽  
Α Particles

A technique has been developed for the absolute determination of nuclear reaction energies by means of a 180° magnetic spectrometer, in which the effective diameter has been measured against a standard scale, and the magnetic field determined by means of a nuclear resonance apparatus. These two measurements, together with the angle of reaction, were the only precise dimensions required. The spectrometer was used to establish a high-voltage scale by means of elastic scattering of protons. Thus sufficient data could be obtained in a nuclear reaction to determine the Q values which are presented in a separate papers. In order to utilize the experimental data efficiently, it was necessary to investigate quantitatively the line shapes in the spectrometer. An empirical method for correcting observed reaction energies for target deterioration is discussed. To obtain verification of the theoretical line shapes for nearly monoenergetic sources, we have measured the Hρ values for several groups of natural α-particles and have obtained the following results, in kilogauss cm : ThC', 427.07± 0.10; ThC α 0 , 354.34; ThCα x , 355.51; Po, 331.76 ± 0.09.

The cross-section and angular distribution of the D-D reactions below 50 keV

1953 ◽  
Vol 216 (1124) ◽  
pp. 57-65 ◽  
Keyword(s):  
Angular Distribution ◽  
Total Cross Section ◽  
Cross Section ◽  
Proportional Counter ◽  
Angular Distributions ◽  
Asymmetry Coefficient ◽  
Gas Target ◽  
The Asymmetry ◽  
The Cross ◽  
Bombarding Energy

A thin gas target was used and the particles from the reactions were detected by a proportional counter. The results show that the total cross-section for the two reactions is the same to within 1%, but that the angular distributions of the products are significantly different. The asymmetry coefficient for the reaction D( d , n ) 3 He is given by 0·31 + 0·0058 E , compared with 0·13 + 0·0047 E for reaction D( d , p ) 3 H, where E is the bombarding energy in kilovolts.

Experiments on the reaction T( d , n ) 4 He II. The angular distribution

1951 ◽  
Vol 204 (1079) ◽  
pp. 500-502 ◽  
Keyword(s):  
Angular Distribution ◽  
Water Vapour ◽  
Heavy Water ◽  
Experimental Error ◽  
Centre Of Mass ◽  
Statistical Accuracy ◽  
Α Particles

A measurement of the angular distribution of α-particles from the T-D reaction has been made by bombarding a heavy-water vapour target with a beam of tritons. Observations were made at three triton energies, 125, 175 and 200 keV, but only with high statistical accuracy at 175 keV. In all cases the disintegration was found to take place symmetrically in centre of mass space within the limits of experimental error.

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