GAMMA–ALPHA REACTIONS IN THE LIGHT NUCLEI OF NUCLEAR EMULSIONS

1964 ◽  
Vol 42 (4) ◽  
pp. 731-761 ◽  
Author(s):  
L. H. Greenberg ◽  
J. P. Roalsvig ◽  
R. N. H. Haslam
Keyword(s):  
Energy Range ◽  
Carbon Content ◽  
Oxygen Content ◽  
Alpha Particle ◽  
Energy Levels ◽  
Maximum Energy ◽  
Light Nuclei ◽  
Nuclear Emulsions ◽  
Maximum Bremsstrahlung Energy ◽  
The University

Ilford E.1 nuclear emulsions were loaded with various amounts of glycerine to vary the content of carbon and of oxygen, and were then irradiated in the beam of the University of Saskatchewan betatron. The numbers of single alpha-particle tracks and of four-pronged alpha-particle stars were correlated to the oxygen content of the plates and the number of three-pronged stars to the carbon content. The yields for the reactions O16(γ, α)C12, O16(γ, 4α), and C12(γ, 3α) for bremsstrahlung of 24-Mev maximum energy were found without confusion with reactions in other nuclides of the emulsion and without having to rely on momentum balances for identification of the events. It was shown that the method of identification of 016(γ, α)C12 events by the measurement of the track of the C12 was not reliable. The large number of alpha tracks in the energy range 4 to 5 Mev, few of which showed a C12 track, was shown to be due largely to reactions in O16. It was also possible, by irradiating emulsions at 17- and at 24-Mev maximum bremsstrahlung energy, to find the energy levels in O16 and in C12 through which the reactions passed.

PROPERTIES OF LIGHT NUCLEI 6He AND 6Be IN THE FRAMEWORK OF THE THREE-CLUSTER MODEL

2021 ◽  
Vol 74 (2) ◽  
pp. 13-18
Author(s):  
О. Bayakhmetov ◽  
◽  
S. Sakhiyev ◽  
V. Pomerantsev ◽  
◽  
...  
Keyword(s):  
Root Mean Square ◽  
Relative Motion ◽  
Alpha Particle ◽  
Energy Levels ◽  
Scientific Work ◽  
Nucleon Nucleon ◽  
Binding Energies ◽  
Light Nuclei ◽  
Mean Square ◽  
Halo Structure

This scientific work is the study of the structure of light nuclei 6He and 6Be in the framework of the three-cluster α+2n-model. The calculation methods have been based on the variational solution of the stationary Schrödinger equation for the relative motion of three clusters in 6He and 6Be nuclei, respectively. The realistic Reid potential has been chosen as the nucleon-nucleon interaction potential, and the potential with even-odd wave splitting has been used for the interaction of the alpha-particle and nucleons. Realistic wave functions of the relative motion of the alpha particle and nucleons in these nuclei and low-lying energy levels have been calculated. The static observables of the 0+ ground state of 6He and 6Be nuclei, in particular, the root-mean-square charge and material radii and binding energies, have been determined. The obtained values of the root-mean-square charge and material radii of the 6He nucleus confirm the hypothesis of the presence of a neutron halo structure of this nucleus.

Nuclear Electrons and Nuclear Structure

2018 ◽  
Author(s):  
Roger H. Stuewer
Keyword(s):  
Nuclear Structure ◽  
Beta Decay ◽  
Gamma Rays ◽  
Alpha Particle ◽  
Continuous Distribution ◽  
Alpha Particles ◽  
Light Nuclei ◽  
Coincidence Method ◽  
Wolfgang Pauli ◽  
Beta Particles

Serious contradictions to the existence of electrons in nuclei impinged in one way or another on the theory of beta decay and became acute when Charles Ellis and William Wooster proved, in an experimental tour de force in 1927, that beta particles are emitted from a radioactive nucleus with a continuous distribution of energies. Bohr concluded that energy is not conserved in the nucleus, an idea that Wolfgang Pauli vigorously opposed. Another puzzle arose in alpha-particle experiments. Walther Bothe and his co-workers used his coincidence method in 1928–30 and concluded that energetic gamma rays are produced when polonium alpha particles bombard beryllium and other light nuclei. That stimulated Frédéric Joliot and Irène Curie to carry out related experiments. These experimental results were thoroughly discussed at a conference that Enrico Fermi organized in Rome in October 1931, whose proceedings included the first publication of Pauli’s neutrino hypothesis.

Energy levels of light nuclei A = 18–20

1972 ◽  
Vol 190 (1) ◽  
pp. 1-18 ◽  
Author(s):  
F. Ajzenberg-Selove
Keyword(s):  
Energy Levels ◽  
Light Nuclei

scholarly journals CROSS-SECTIONS FOR PHOTONUCLEAR REACTIONS 93Nb(γ,n)92mNb AND 93Nb(γ,n)92tNb IN THE END-POINT BREMSSTRAHLUNG ENERGIES 36...91 MeV

2020 ◽  
pp. 148-153
Author(s):  
A.N. Vodin ◽  
O.S. Deiev ◽  
I.S. Timchenko ◽  
S.N. Olejnik ◽  
A.S. Kachan ◽  
...  
Keyword(s):  
Energy Range ◽  
Cross Sections ◽  
Maximum Energy ◽  
Reaction Cross ◽  
Bremsstrahlung Spectrum ◽  
Photonuclear Reactions ◽  
End Point ◽  
Γ Ray ◽  
First Time ◽  
Good Agreement

The flux-weighted averaged over the energy range of bremsstrahlung spectrum from reaction threshold up to the maximum energy of γ-ray cross-sections <σ(E)> of the 93Nb(γ,n)92mNb and 93Nb(γ,n)92tNb photonuclear reactions were determined by the gamma-activation method within the end-point bremsstrahlung energies Еmax = 36…91 MeV. Activation of 93Nb targets has been done by a bremsstrahlung flux using an electron beam at the linear accelerator LUE-40 at RDC "Accelerator" NSC KIPT. The γ-ray spectra of irradiated targets were registered using the HPGe detector with an energy resolution of 1.8 keV for the 1332 keV line 60Co. To control the bremsstrahlung flux we used natMo witness-targets and a reaction cross-section of 100Mo(γ,n)99Mo. Obtained experimental cross-sections <σ(E)> of the studied reactions are in good agreement with the theoretical values calculated within TALYS 1.9 code and the results of other authors. The averaged cross-sections <σ(E)> of the 93Nb(γ,n)92mNb and 93Nb(γ,n)92tNb reactions in the energy range 35...45 MeV and > 70 MeV were obtained for the first time.

scholarly journals Энерговыделение при бомбардировке атомами дейтерия поверхности вольфрама

2019 ◽  
Vol 45 (11) ◽  
pp. 51
Author(s):  
Д.С. Мелузова ◽  
П.Ю. Бабенко ◽  
М.И. Миронов ◽  
В.С. Михайлов ◽  
А.П. Шергин ◽  
...  
Keyword(s):  
Energy Loss ◽  
Energy Range ◽  
Energy Release ◽  
Maximum Energy ◽  
Wide Energy Range ◽  
Tokamak Reactor ◽  
Tungsten Target ◽  
Wide Energy ◽  
Bragg Maximum ◽  
Maximum Energy Release

The distribution of energy release (linear energy loss) over depth was calculated when bombarded with deuterium atoms of a tungsten target in a wide energy range of incident particles of 100 eV - 10 MeV. It is shown that in the energy range up to 100 keV, the maximum energy release, contrary to the prevailing ideas, is near the surface of a solid. At energies above 100 keV, the nature of the distribution changes and the Bragg maximum appears near the point where the particle stops. The distribution of the energy release over depth in tungsten is obtained for conditions typical of the ITER tokamak reactor, which makes it possible to estimate the wall heating during bombardment by plasma atoms.

Energy levels of light nuclei A = 16–17

1982 ◽  
Vol 375 (1) ◽  
pp. 1-168 ◽  
Author(s):  
F. Ajzenberg-Selove
Keyword(s):  
Energy Levels ◽  
Light Nuclei

Solar neutron flux in the energy range 20–160 MeV

1970 ◽  
Vol 48 (18) ◽  
pp. 2155-2161 ◽  
Author(s):  
C. Y. Kim
Keyword(s):  
Neutron Flux ◽  
Energy Range ◽  
Sunspot Number ◽  
Solar Flares ◽  
Energy Region ◽  
High Energy ◽  
The Sun ◽  
Solar Neutron ◽  
Nuclear Emulsions ◽  
The Difference

An attempt to measure the flux of high-energy solar neutrons was made by measuring the difference in flux from the direction of the sun and from the symmetrical direction about the zenith, using oriented nuclear emulsions flown by balloon on July 30, 1966 from Fort Churchill, Manitoba.An excess of (2.2 ± 2.5) × 10−2 neutrons cm−2 s−1 was observed from the direction of the sun in the energy region of 20–160 MeV. On the day of the flight the sunspot number was 63, and no major solar flares were reported.

The Fermi Level

2020 ◽  
pp. 267-300
Author(s):  
Brian Cantor
Keyword(s):  
Fermi Level ◽  
Atomic Bomb ◽  
Energy Levels ◽  
Pauli Exclusion Principle ◽  
Mean Free Path ◽  
Maximum Energy ◽  
Exclusion Principle ◽  
Energy Bands ◽  
Anti Semitism ◽  
Dielectric Effect

The Fermi level is the maximum energy of the electrons in a material. Effectively there is a Fermi equation: EF = E max. This chapter examines the discrete electron energy levels in individual atoms as a consequence of the Pauli exclusion principle, the corresponding energy bands in a material composed of many atoms or molecules, and the way in which conductor, insulator and semiconductor materials depend on the position of the Fermi level relative to the energy bands. It explains: the concepts of electron mobility, mean free path and conductivity; the dielectric effect and capacitance; p-type, n-type, intrinsic and extrinsic semiconductors; and the behaviour of some simple microelectronic devices. Enrico Fermi was the son of a minor railway official in Rome. He had a meteoric scientific career in Italy, developing Fermi-Dirac statistics for the energies of fundamental fermion particles (such as electrons and protons), discovering the neutrino, and explaining the behaviour of different materials under bombardment from fast and slow neutrons. After initially joining Mussolini’s Fascist Party, he became unhappy at the level of anti-Semitism (his wife was Jewish) and left suddenly for America, immediately after receiving the Nobel Prize in Sweden. At Columbia and Chicago Universities and at Los Alamos National Labs, he played a key scientific role in developing controlled fission in an atomic pile, leading to the development of the atomic bomb towards the end of the Second World War, and the nuclear energy industry after the war.

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