Ionization in collisions between 30–1000 keV antiprotons and atomic hydrogen

1996 ◽  
Vol 74 (7-8) ◽  
pp. 490-495 ◽  
Author(s):  
K. Paludan ◽  
H. Knudsen ◽  
U. Mikkelsen ◽  
M. Charlton ◽  
K. Kirsebom ◽  
...  
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Atomic Hydrogen ◽  
Theoretical Calculations ◽  
Published Data ◽  
Ionization Cross ◽  
Ionization Cross Sections ◽  
Impact Energies ◽  
Theoretical Results

Recently published data for impact of antiprotons in the energy range 30–1000 keV on atomic hydrogen are compared with analogous proton, electron, and positron measurements, and it is found that the ionization cross sections of atomic hydrogen follow the same pattern as similar cross sections obtained on He and H2 targets, in accordance with the general phenomenological description of single ionization that has developed over the last decade. Further comparisons are made with various recent and advanced theoretical calculations for antiproton ionization of atomic hydrogen. These theoretical results agree well with the data obtained, but for lower impact energies the different methods do not, despite the simplicity of the system, agree on predicting even the form of the cross section.

Single ionization by positron impact

1996 ◽  
Vol 74 (7-8) ◽  
pp. 367-372 ◽  
Author(s):  
J. Moxom ◽  
P. Ashley ◽  
G. Laricchia
Keyword(s):  
Energy Range ◽  
Cross Sections ◽  
Positron Impact ◽  
Ionization Cross ◽  
Positron Scattering ◽  
Direct Ionization ◽  
Low Energies ◽  
Ionization Cross Sections ◽  
Impact Energies ◽  
Existing Data

The single direct ionization cross sections for positron scattering [Formula: see text] on He, Ar, Kr, and H2 were measured and compared with existing data and the corresponding cross sections for electron impact [Formula: see text]. At most impact energies the present data for He and H2 are in reasonable accord with other measurements and, in the case of He, with some of the available calculations. At low energies, [Formula: see text] is found to increase more slowly than [Formula: see text], probably due to the importance of Ps formation in this energy range.

Ionization by protons in the energy range 100 to 450 keV

1963 ◽  
Vol 274 (1358) ◽  
pp. 365-370 ◽  
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Ionization Cross Section ◽  
Axial Magnetic Field ◽  
High Energy ◽  
Ionization Cross ◽  
Total Ionization ◽  
Ion Production ◽  
Ionization Cross Sections

Ionization by protons in the energy range 100 to 450 keV has been investigated by means of the well-known parallel-plate condenser method. A uniform axial magnetic field enables slow ion collection to be carried out over a precisely determined path length at pressures low enough to ensure single collision conditions. The total cross-section for slow ion production cr+, and the total ionization cross-section have been determined for protons in hydrogen, helium , neon, argon and krypton. It is found that charge transfer is very small above about 200 keV so that cr+ ~ cr e . The ionization cross-section for all cases falls off as E -1 log E where E is the energy of relative motion. At the high-energy limit of the present measurements, the proton ionization cross-sections agree closely with electron ionization cross-sections for the same relative velocity of impact. The results are therefore in agreement with the general predictions of the Born approximation.

scholarly journals He2+ Impact Single Ionization Cross Sections of Fe Atom

2020 ◽  
Vol 6 (2) ◽  
pp. 127-133
Author(s):  
S. P. Gupta ◽  
K. Yadav ◽  
R. Khanal ◽  
L. K. Jha
Keyword(s):  
Energy Range ◽  
Cross Sections ◽  
Impact Energy ◽  
Theoretical Calculations ◽  
Ionization Cross ◽  
Single Ionization ◽  
Hartree Fock ◽  
Ionization Cross Sections ◽  
Binary Encounter Approximation ◽  
The Given

Binary encounter approximation has been used for theoretical calculations of alpha particle (He2+) impact single ionization cross sections of iron atom at ground state in the energy range of 35 to 360 keV/amu. The cross sections for energy transfer given by Vriens’ and quantum mechanical Hartree-Fock velocity distributions for target electron have been used in the calculation. The contributions in total single ionization cross sections from 4s and 3d subshells are observed to be higher than from 3p, and the contributions from 4s decreases with increase of impact energy whereas the contribution from 3d increases. The total single ionization cross sections decrease gradually with the increase of impact energy similar to experimental results which implies that our results are in satisfactory agreement with the experimental data in the given energy range.

Absolute cross sections for D2 Lyman and Werner band excitation by controlled electron impact

1984 ◽  
Vol 62 (1) ◽  
pp. 1-9 ◽  
Author(s):  
K. Becker ◽  
J. W. McConkey
Keyword(s):  
Energy Range ◽  
Electron Impact ◽  
Cross Section ◽  
Cross Sections ◽  
Impact Energy ◽  
Emission Cross Section ◽  
Direct Excitation ◽  
The Cross ◽  
Impact Energies

We have studied the Lyman [Formula: see text] and Werner [Formula: see text] band emissions produced by 20–500-eV electrons incident on molecular deuterium, D2. Emission cross sections of (3.7 ± 0.9) × 10−17 cm2 for the B → X and (3.54 ± 0.74) × 10−17 cm2 for the C → X system have been determined at 100-eV impact energy. Cascading did not play an important role in the [Formula: see text] emission, but it was shown to affect the [Formula: see text] emission seriously, particularly for impact energies below 50 eV. We estimate the cross section for direct excitation of the [Formula: see text] state and the cascade cross section to be 2.95 × 10−17 and 0.75 × 10−17 cm2, at 100 eV respectively. The cascade cross section is 20 ± 10% of the total B → X emission cross section, and is essentially constant in the energy range 300–50 eV, but increases significantly for lower impact energies, e.g., to 40 ± 15% at 27.5 eV. The cross section for the atomic 2p → 1s Lyman α emission from D2 has also been measured and the value of 1.00 × 10−17 cm2 at 100 eV is 20% smaller than the cross section for Lyman α emission from H2.

Cross Section Ratios for the Electron Impact Production of Singly and Multiply Ionized Rare Gas Ions

1978 ◽  
Vol 33 (9) ◽  
pp. 1111-1113 ◽  
Author(s):  
F. Egger ◽  
T. D. Mark
Keyword(s):  
Electron Impact ◽  
Cross Section ◽  
Mass Spectrometer ◽  
Cross Sections ◽  
Impact Ionization ◽  
Rare Gas ◽  
Ionization Cross ◽  
Single Ionization ◽  
Multiple Ionization ◽  
Ionization Cross Sections

Electron impact ionization of He, Ne, Ar, Kr and Xe has been studied with a double focussing mass spectrometer Varian MAT CH5. Ratios of various multiple ionization cross sections with respect to single ionization cross sections for He, Ne, Ar, Kr and Xe at electron energies of 50, 100 and 150eV are given. These cross section ratios are com­pared with previous determinations.

scholarly journals Electron-loss and target ionization cross sections for water vapor by 20–150keV neutral atomic hydrogen impact

2006 ◽  
Vol 421 (1-3) ◽  
pp. 68-71 ◽  
Author(s):  
F. Gobet ◽  
S. Eden ◽  
B. Coupier ◽  
J. Tabet ◽  
B. Farizon ◽  
...  
Keyword(s):  
Water Vapor ◽  
Cross Sections ◽  
Atomic Hydrogen ◽  
Electron Loss ◽  
Ionization Cross ◽  
Ionization Cross Sections

Charge transfer in the presence of a radiation field

1998 ◽  
Vol 76 (3) ◽  
pp. 245-250 ◽  
Author(s):  
S -M Li ◽  
J -G Khou ◽  
Z -F Zhou ◽  
J Chen ◽  
Y -Y Liu
Keyword(s):  
Charge Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Born Approximation ◽  
Atomic Hydrogen ◽  
Capture Cross ◽  
Exchange Collision ◽  
Increasing Functions ◽  
Theoretical Results ◽  
Capture Cross Sections

In the first Born approximation, the dressing modification in laser-assisted charge exchange collision is investigated. The crosssections for electron capture by a proton from dressed atomic hydrogen and dressed helium targets are calculated within awide energy range. Theoretical results show that with impact energy increasing, the dressing effect leads to increasingly significant cross-section modifications. The modified capture cross sections are increasing functions of the ratio of laser strength to frequency. PACS Nos.: 34.50.Rk; 34.70.+e; 32.80.Wr; and 34.90.+q

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