scholarly journals Effect of Coulomb Focusing on the Electron–Atom Bremsstrahlung Cross Section for Tungsten and Iron in Nonthermal Lorentzian Plasmas

2020 ◽  
Vol 10 (14) ◽  
pp. 4832
Author(s):  
Myoung-Jae Lee ◽  
Naoko Ashikawa ◽  
Young-Dae Jung
Keyword(s):  
Cross Section ◽  
Atomic Charge ◽  
Bremsstrahlung Spectrum ◽  
Nonthermal Electron ◽  
Emission Rates ◽  
Focusing Effect ◽  
Nonthermal Electrons ◽  
Electron Atom ◽  
Bremsstrahlung Emission ◽  
Bremsstrahlung Process

The Coulomb focusing effect on the electron–atom bremsstrahlung spectrum is investigated in nonthermal Lorentzian plasmas. The universal expression of the cross section of nonrelativistic electron–atom bremsstrahlung process is obtained by the solution of the Thomas-Fermi equation with the effective atomic charge. The effective Coulomb focusing for the electron–atom bremsstrahlung cross section near the threshold domain is also investigated by adopting the modified Elwert-Sommerfeld factor with the mean effective charge for the bremsstrahlung process. In addition, the bremsstrahlung emission rates are obtained by considering encounters between nonthermal electrons and atoms such as Fe and W atoms. We found that the bremsstrahlung emission rates for nonthermal electron–atoms are lower than those for thermal plasmas. Various nonthermal effects on the bremsstrahlung emission rates in Lorentzian plasmas are also discussed.

Effects of Grain Size on the Bremsstrahlung Spectrum of Electron-Dust Grain Collisions in Dusty Plasmas

2009 ◽  
Vol 64 (3-4) ◽  
pp. 229-232
Author(s):  
Seo-Hee Kim ◽  
Young-Dae Jung
Keyword(s):  
Grain Size ◽  
Cross Section ◽  
Dusty Plasmas ◽  
Bremsstrahlung Spectrum ◽  
Final States ◽  
Bremsstrahlung Radiation ◽  
Dust Charge ◽  
Bremsstrahlung Emission ◽  
Debye Radius ◽  
Dust Grain

Abstract The grain size effects on the bremsstrahlung emission spectrum due to nonrelativisitc electrondust grain collisions are investigated in dusty plasmas. Using the Born approximation for the initial and final states of the projectile electron, the bremsstranhlung radiation cross section is obtained as a function of the grain size, dust charge, Debye radius, collision energy, and radiation photon energy. It is found that the effects of the grain size enhance the bremsstrahlung radiation cross section, especially for soft-photon radiations. The effect of the Debye radius on the bremsstrahlung cross section is found to be increased with an increase of the magnitude of the charge number of the dust grain. In addition, the grain size effect on the bremsstrahlung spectrum is found to be more significant for highly charged dusty grains

The influence of the nuclear and atomic form factors on the muon bremsstrahlung cross section

1968 ◽  
Vol 46 (10) ◽  
pp. S377-S380 ◽  
Author(s):  
A. A. Petrukhin ◽  
V. V. Shestakov
Keyword(s):  
Form Factor ◽  
Cross Section ◽  
Born Approximation ◽  
Form Factors ◽  
Experimental Results ◽  
Simple Analytical Expression ◽  
Nuclear Form Factor ◽  
The Cross ◽  
Atomic Electrons ◽  
Bremsstrahlung Process

The cross section for the muon bremsstrahlung process is calculated as a function of the nuclear form factor in the Born approximation following the Bethe and Heitler theory. The influence of the nuclear form factor is greater than that taken by Christy and Kusaka. The simple analytical expression for the effect of the screening of the atomic electrons is found. The influence of a decrease in the cross section upon the interpretation of some experimental results is estimated.

scholarly journals Quantitative Ausmessung des Brom-Affinitätskontinuums und Bestimmung der Detachment-und Attachment-Querschnitte

1970 ◽  
Vol 25 (11) ◽  
pp. 1617-1626 ◽  
Author(s):  
H. Frank ◽  
M. Neiger ◽  
H.-P. Popp
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Electron Affinity ◽  
Elastic Cross Section ◽  
Electron Atom ◽  
Intensity Measurements ◽  
Long Wave ◽  
The Mean ◽  
Intense Electron

Abstract A wall stabilized low-current cylindric arc was used to produce the radiation of the negative Bromine-ions. The radiation consists of an affinity-continuum with a long-wave threshold of 3682 Å, yielding an electron affinity for Bromine of 3.366 eV, and of an intense electron-atom Bremsstrahlung in the visible. Intensity measurements of the continua allow the determination of the photo-detachment-and attachment-cross-sections of Bromine and also the determination of the mean elastic cross-section of electrons against Bromine atoms.

Collective Effects on the Transition Bremsstrahlung Spectrum due to the Polarization Interaction in Nonideal Plasmas

2009 ◽  
Vol 64 (1-2) ◽  
pp. 49-53
Author(s):  
Hwa-Min Kim ◽  
Young-Dae Jung
Keyword(s):  
Cross Section ◽  
Impact Parameter ◽  
Photon Energy ◽  
Parameter Analysis ◽  
Collective Effects ◽  
Bremsstrahlung Spectrum ◽  
Collective Effect ◽  
Bremsstrahlung Radiation ◽  
Polarization Interaction ◽  
Nonideal Plasmas

The collective effects on the transition bremsstrahlung spectrum due to the polarization interaction between the electron and Debye shielding cloud of an ion are investigated in nonideal plasmas. The impact parameter analysis with the effective pseudopotential model taking into account the nonideal collective and plasma screening effects is applied to obtain the bremsstrahlung radiation cross-section as a function of the nonideality plasma parameter, Debye length, photon energy, and projectile energy. It is shown that the collective effects enhance the bremsstrahlung radiation cross-section and decrease with increasing impact parameter. It is also shown that the collective effect is the most significant near the maximum position of the bremsstrahlung cross-section. In addition, it is shown that the collective effect decreases with an increase of the radiation photon energy

Experimental determination of the differential cross-section surface for elastic electron–atom (molecule) scattering

2006 ◽  
Vol 39 (3) ◽  
pp. 609-623 ◽  
Author(s):  
A R Milosavljević ◽  
S Madžunkov ◽  
D Šević ◽  
I Čadež ◽  
B P Marinković
Keyword(s):  
Differential Cross Section ◽  
Experimental Determination ◽  
Cross Section ◽  
Differential Cross ◽  
Elastic Electron ◽  
Electron Atom ◽  
Section Surface ◽  
Molecule Scattering

An Improved Calculation of the Multiphoton Bremsstrahlung Process in the Presence of a Laser Beam

1977 ◽  
Vol 30 (1) ◽  
pp. 33
Author(s):  
Rama Acharya ◽  
Man Mohan
Keyword(s):  
Laser Beam ◽  
Cross Section ◽  
Coulomb Field ◽  
Final States ◽  
The Cross ◽  
Bremsstrahlung Process

It has been noted previously that analyses of free-free transitions in the presence of an ion are appreciably affected by neglecting the Coulomb field of the ion at infinity. We have therefore made here an improved calculation of the cross section for the multiphoton bremsstrahlung process by taking account of the Coulomb field in the initial and final states.

The small-angle scattering of photons of about 100 MeV energy

1960 ◽  
Vol 254 (1277) ◽  
pp. 242-258 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Primary Source ◽  
Bremsstrahlung Spectrum ◽  
Differential Cross Sections ◽  
Approximate Theory ◽  
Cerenkov Counter ◽  
Scattering Cross ◽  
Angle Scattering

Differential cross-sections have been measured for the scattering of photons of mean energy 87 MeV by uranium at eight angles in the range from 1.18 to 4.48 mrad and by aluminium, silver, tungsten, lead and uranium at angles of 1.89 and 4.24 mrad, using a narrowly collimated bremsstrahlung beam from the Oxford 110 MeV synchrotron as the primary source of photons. A biased total-absorption Čerenkov counter was used to detect photons with energies near the peak energy of the bremsstrahlung spectrum, and absolute differential cross-sections were measured by comparing counting rates for photons in the primary and scattered beams. The experimental results, with the differential Compton scattering cross-sections of Klein and Nishina subtracted, were analyzed in terms of their variation with angle and atomic number, and can be described as consisting of a sharply peaked angular distribution with absolute cross-sections varying from element to element as Z 4 , together with a uniform distribution varying nearly as Z 2 ; these distributions were identified with Delbruck scattering and with bremsstrahlung from secondary electrons in the scattering target, respectively. The Delbruck scattering cross-section thus determined is slightly more sharply peaked than the cross-section predicted by an approximate theory of Bethe & Rohrlich.

scholarly journals BREMSSTRAHLUNG EMISSION DURING α-DECAY OF 226Ra

2008 ◽  
Vol 23 (31) ◽  
pp. 2651-2663 ◽  
Author(s):  
GIORGIO GIARDINA ◽  
GIOVANNI FAZIO ◽  
GIUSEPPE MANDAGLIO ◽  
MARINA MANGANARO ◽  
SERGHEI P. MAYDANYUK ◽  
...  
Keyword(s):  
Quantum Mechanical Calculation ◽  
Bremsstrahlung Spectrum ◽  
Quantum Mechanical ◽  
Destructive Interference ◽  
Α Decay ◽  
Mechanical Calculation ◽  
Bremsstrahlung Emission ◽  
Photon Spectra ◽  
Theory And Experiment ◽  
Good Agreement

We obtained the spectrum of probability of the bremsstrahlung emission accompanying the α-decay of 226 Ra (Eα = 4.8 MeV ) by measuring the α-γ coincidences and using the model presented in our previous study on the α-decay of 214 Po (Eα = 7.7 MeV ). We compare the experimental data with the quantum mechanical calculation and find a good agreement between theory and experiment. We discuss the differences between the photon spectra connected with the α-decay of the 226 Ra and 214 Po nuclei. For the two mentioned nuclei, we analyze the bremsstrahlung emission contributions from the tunneling and external regions of the nucleus barrier into the total spectrum, and we find the destructive interference between these contributions. We also find that the emission of photons during tunneling of the α-particle gives an important contribution to the bremsstrahlung spectrum in the whole Eγ energy range of the studied 226 Ra nucleus.

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