Author: D. E. Golden
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
The Ramsauer technique has been used to measure the absolute total electron-helium-atom scattering cross section as a function of electron energy from 0.30 to 28 eV with an estimated probable error of =3%. No 'fine structure' has been observed at the lower electron energies studied. The variation of the cross section with energy for energies less than 3 eV is in reasonable agreement with the modified effective-range formula given by O'Malley, using a scattering length of 1.15a sub o. The cross section first increases with decreasing electron energy from 2.2 A sq at 28.0 eV to a maximum of 5.6 A sq at about 1.2 eV and then decreases to 5.4 A sq at 0.300 eV. The cross section has been found to decrease sharply with increasing energy at about 0.5 eV below the first excitation energy. This resonance, predicted by Baranger and Gerjuoy and originally observed by Schulz, first decreases with increasing energy to a minimum of about 10% below the background at 19.285=0.025 eV and then increases to a gentle maximum of about 3% above the background at 19.65=0.05 eV. The resolution of this resonance as well as the 10% decrease in the cross section at the minimum is determined by the half-width of the electron beam at this energy which is about 0.1 eV. (Author).
Absolute Total Electron-helium-atom Scattering Cross Sections for Low Electron Energies
Author: D. E. Golden
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
The Ramsauer technique has been used to measure the absolute total electron-helium-atom scattering cross section as a function of electron energy from 0.30 to 28 eV with an estimated probable error of =3%. No 'fine structure' has been observed at the lower electron energies studied. The variation of the cross section with energy for energies less than 3 eV is in reasonable agreement with the modified effective-range formula given by O'Malley, using a scattering length of 1.15a sub o. The cross section first increases with decreasing electron energy from 2.2 A sq at 28.0 eV to a maximum of 5.6 A sq at about 1.2 eV and then decreases to 5.4 A sq at 0.300 eV. The cross section has been found to decrease sharply with increasing energy at about 0.5 eV below the first excitation energy. This resonance, predicted by Baranger and Gerjuoy and originally observed by Schulz, first decreases with increasing energy to a minimum of about 10% below the background at 19.285=0.025 eV and then increases to a gentle maximum of about 3% above the background at 19.65=0.05 eV. The resolution of this resonance as well as the 10% decrease in the cross section at the minimum is determined by the half-width of the electron beam at this energy which is about 0.1 eV. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
The Ramsauer technique has been used to measure the absolute total electron-helium-atom scattering cross section as a function of electron energy from 0.30 to 28 eV with an estimated probable error of =3%. No 'fine structure' has been observed at the lower electron energies studied. The variation of the cross section with energy for energies less than 3 eV is in reasonable agreement with the modified effective-range formula given by O'Malley, using a scattering length of 1.15a sub o. The cross section first increases with decreasing electron energy from 2.2 A sq at 28.0 eV to a maximum of 5.6 A sq at about 1.2 eV and then decreases to 5.4 A sq at 0.300 eV. The cross section has been found to decrease sharply with increasing energy at about 0.5 eV below the first excitation energy. This resonance, predicted by Baranger and Gerjuoy and originally observed by Schulz, first decreases with increasing energy to a minimum of about 10% below the background at 19.285=0.025 eV and then increases to a gentle maximum of about 3% above the background at 19.65=0.05 eV. The resolution of this resonance as well as the 10% decrease in the cross section at the minimum is determined by the half-width of the electron beam at this energy which is about 0.1 eV. (Author).
Measurement of Absolute Total Cross Sections for the Scattering of Electrons by He, H2, CH4 and CCl[subscript N]F[subscript M]
Author: Robert K. Jones
Publisher:
ISBN:
Category : Cross sections (Nuclear physics)
Languages : en
Pages : 246
Book Description
Publisher:
ISBN:
Category : Cross sections (Nuclear physics)
Languages : en
Pages : 246
Book Description
Absolute Measurements of Total Cross Sections for the Scattering of Low-energy Electrons by Atomic and Molecular Oxygen
Author: Gabriel Sunshine
Publisher:
ISBN:
Category :
Languages : en
Pages : 39
Book Description
The atom beam recoil technique was used to measure absolute total cross sections for the scattering of electrons by atomic and molecular oxygen at 22 energies between 0.5 and 11.3 eV, with additional data obtained up to 100 eV. In this method, a modulated electron beam cross-fires an atom beam, whose attenuation at the modulation frequency is observed. The angular resolution in the electron polar scattering angle ranges from about 15.6 degrees at 1 eV to 9.6 degrees at 12 eV, for 0, and from about 18.5 degrees at 1 eV to 11.4 degrees at 12 eV, for 02. Our absolute values for 02 between 0.5 and 11.3 eV are between 10 and 20% higher than those of Bruche, while the shape of the curve agrees well. The atomic cross sections vary from about 5.3 sq. A at 0.5 eV to 8.3 sq. A at 11.3 eV, with an estimated error of 20% except for the 0.5 eV point which has an error of 30%. These results are in excellent agreement with semi-empirical calculations of Cooper and Martin and Robinson and Geltman, as well as with the polarized orbitals calculation of Temkin. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 39
Book Description
The atom beam recoil technique was used to measure absolute total cross sections for the scattering of electrons by atomic and molecular oxygen at 22 energies between 0.5 and 11.3 eV, with additional data obtained up to 100 eV. In this method, a modulated electron beam cross-fires an atom beam, whose attenuation at the modulation frequency is observed. The angular resolution in the electron polar scattering angle ranges from about 15.6 degrees at 1 eV to 9.6 degrees at 12 eV, for 0, and from about 18.5 degrees at 1 eV to 11.4 degrees at 12 eV, for 02. Our absolute values for 02 between 0.5 and 11.3 eV are between 10 and 20% higher than those of Bruche, while the shape of the curve agrees well. The atomic cross sections vary from about 5.3 sq. A at 0.5 eV to 8.3 sq. A at 11.3 eV, with an estimated error of 20% except for the 0.5 eV point which has an error of 30%. These results are in excellent agreement with semi-empirical calculations of Cooper and Martin and Robinson and Geltman, as well as with the polarized orbitals calculation of Temkin. (Author).
A Measurement of the Absolute Total Cross Sections for High Energy Electrons on Helium
Author: Brian K. Thomas
Publisher:
ISBN:
Category :
Languages : en
Pages : 76
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 76
Book Description
NBS Special Publication
Author:
Publisher:
ISBN:
Category : Weights and measures
Languages : en
Pages : 858
Book Description
Publisher:
ISBN:
Category : Weights and measures
Languages : en
Pages : 858
Book Description
Government-wide Index to Federal Research & Development Reports
Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 760
Book Description
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 760
Book Description
Nuclear Science Abstracts
Author:
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 658
Book Description
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 658
Book Description
Bibliography of Low Energy Electron Collision Cross Section Data
Author: Lee Joseph Kieffer
Publisher:
ISBN:
Category : Collisions (Nuclear physics)
Languages : en
Pages : 98
Book Description
A bibliography of low energy electron collision cross section data is prese * nted.Only references which report original measurements or calculations of electron collision cross sections are included.The cross section data for each process are listed by atomic species in order of their atomic number.The data for molecules are listed in arbitrary order. (Author).
Publisher:
ISBN:
Category : Collisions (Nuclear physics)
Languages : en
Pages : 98
Book Description
A bibliography of low energy electron collision cross section data is prese * nted.Only references which report original measurements or calculations of electron collision cross sections are included.The cross section data for each process are listed by atomic species in order of their atomic number.The data for molecules are listed in arbitrary order. (Author).
Fundamentals of Gaseous Ionization and Plasma Electronics
Author: Essam Nasser
Publisher: John Wiley & Sons
ISBN:
Category : Science
Languages : en
Pages : 488
Book Description
Publisher: John Wiley & Sons
ISBN:
Category : Science
Languages : en
Pages : 488
Book Description
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 388
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 388
Book Description