A new parameter for describing the reflection coefficient of light ions: Scaled transport cross section

1990 ◽  
Vol 48 (1-4) ◽  
pp. 444-447 ◽  
Author(s):  
Zhengming Luo
Keyword(s):  
Reflection Coefficient ◽  
Cross Section ◽  
Transport Cross Section ◽  
Light Ions

MONTE CARLO CALCULATION OF SLOW ELECTRON BEAM TRANSPORT IN SOLIDS: REFLECTION COEFFICIENT THEORY IMPLICATIONS

2012 ◽  
Vol 26 (04) ◽  
pp. 1150022 ◽  
Author(s):  
A. BENTABET
Keyword(s):  
Monte Carlo ◽  
Electron Transport ◽  
Reflection Coefficient ◽  
Penetration Depth ◽  
Cross Section ◽  
Monte Carlo Code ◽  
Slow Electron ◽  
Backscattering Coefficient ◽  
Transport Cross Section ◽  
The Mean

The reflection coefficient theory developed by Vicanek and Urbassek showed that the backscattering coefficient of light ions impinging on semi-infinite solid targets is strongly related to the range and the first transport cross-section as well. In this work and in the electron case, we show that not only the backscattering coefficient is, but also most of electron transport quantities (such as the mean penetration depth, the diffusion polar angles, the final backscattering energy, etc.), are strongly correlated to both these quantities (i.e. the range and the first transport cross-section). In addition, most of the electron transport quantities are weakly correlated to the distribution of the scattering angle and the total elastic cross-section as well. To make our study as straightforward and clear as possible, we have projected different input data of elastic cross-sections and ranges in our Monte Carlo code to study the mean penetration depth and the backscattering coefficient of slow electrons impinging on semi-infinite aluminum and gold in the energy range up to 10 keV. The possibility of extending the present study to other materials and other transport quantities using the same models is a valid process.

scholarly journals Reflection of keV light ions from solids at oblique and grazing incidence

2009 ◽  
Vol 24 (3) ◽  
pp. 188-194 ◽  
Author(s):  
Jovan Vukanic ◽  
Rodoljub Simovic
Keyword(s):  
Reflection Coefficient ◽  
Multiple Scattering ◽  
Cross Section ◽  
Scattering Theory ◽  
Grazing Incidence ◽  
Universal Functions ◽  
Light Ions ◽  
Analytical Formulae ◽  
Analytical Approaches ◽  
Good Agreement

The particle reflection coefficient of light keV ions backscattered from heavy targets has been determined by two different analytical approaches: by the single collision model in the case of nearly perpendicular incidence and by the small-angle multiple scattering theory in the case of glancing angles of incidence. The obtained analytical formulae are approximately universal functions of the scaled transport cross-section describing the reflection of all light ions from heavy targets. Going from perpendicular to grazing incidence, the transition from pure single to pure multiple scattering type of reflection is observed. For larger values of the scaling parameter the results of these theories cover the whole region of ion incident angles and the present estimates of the particle reflection coefficient are in good agreement with the results obtained from the empirical formula of Tabata et al.

scholarly journals Are Further Cross Section Measurements Necessary for Space Radiation Protection or Ion Therapy Applications? Helium Projectiles

2020 ◽  
Vol 8 ◽  
Author(s):  
John W. Norbury ◽  
Giuseppe Battistoni ◽  
Judith Besuglow ◽  
Luca Bocchini ◽  
Daria Boscolo ◽  
...  
Keyword(s):  
Radiation Protection ◽  
Cross Section ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Production Cross ◽  
Cosmic Ray ◽  
Space Radiation ◽  
Radiation Shielding ◽  
Light Ions ◽  
Ion Therapy

The helium (4He) component of the primary particles in the galactic cosmic ray spectrum makes significant contributions to the total astronaut radiation exposure. 4He ions are also desirable for direct applications in ion therapy. They contribute smaller projectile fragmentation than carbon (12C) ions and smaller lateral beam spreading than protons. Space radiation protection and ion therapy applications need reliable nuclear reaction models and transport codes for energetic particles in matter. Neutrons and light ions (1H, 2H, 3H, 3He, and 4He) are the most important secondary particles produced in space radiation and ion therapy nuclear reactions; these particles penetrate deeply and make large contributions to dose equivalent. Since neutrons and light ions may scatter at large angles, double differential cross sections are required by transport codes that propagate radiation fields through radiation shielding and human tissue. This work will review the importance of 4He projectiles to space radiation and ion therapy, and outline the present status of neutron and light ion production cross section measurements and modeling, with recommendations for future needs.

scholarly journals CHARGE INFLUENCE ON MINI BLACK HOLE'S CROSS SECTION

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1265-1269
Author(s):  
R. S. CARAÇA ◽  
M. MALHEIRO
Keyword(s):  
Cross Section ◽  
Electric Charge ◽  
Mass Ratio ◽  
Horizon Radius ◽  
Maximum Charge ◽  
Light Ions ◽  
Ratio Condition ◽  
The Cross ◽  
Mini Black Holes ◽  
Section Production

In this work we study the electric charge effect on the cross section production of charged mini black holes (MBH) in accelerators. We analyze the charged MBH solution using the fat brane approximation in the context of the ADD model. The maximum charge–mass ratio condition for the existence of a horizon radius is discussed. We show that the electric charge causes a decrease in this radius and, consequently, in the cross section. This reduction is negligible for protons and light-ions but can be important for heavy-ions.

Phonon Transport in Anisotropic Scattering Particulate Media

2003 ◽  
Vol 125 (6) ◽  
pp. 1156-1162 ◽  
Author(s):  
Ravi Prasher
Keyword(s):  
Cross Section ◽  
Acoustic Waves ◽  
Transport Theory ◽  
Mode Conversion ◽  
Anisotropic Scattering ◽  
Phonon Transport ◽  
Isotropic Scattering ◽  
Radiative Transport ◽  
Particulate Media ◽  
Transport Cross Section

Equation of phonon radiative transport (EPRT) is rewritten to include anisotropic scattering by a particulate media by including an acoustic phase function and an inscattering term which makes EPRT exactly same as equation of radiative transport (ERT). This formulation of EPRT is called generalized EPRT (GEPRT). It is shown that GEPRT reduces to EPRT for isotropic scattering and is totally consistent with phonon transport theory, showing that transport cross section is different from the scattering cross section. GEPRT leads to same formulation for transport cross section as given by phonon transport theory. However GEPRT shows that transport cross section formulations as described by phonon transport theory are only valid for acoustically thick medium. Transport cross section is different for the acoustically thin medium leading to the conclusion that mean free path (m.f.p) is size dependant. Finally calculations are performed for two types of scatterers for acoustic waves without mode conversion: (1) acoustically hard Rayleigh sphere; and (2) large sphere in the geometrical scattering regime. Results show that the scattering from these particles is highly anisotropic. It is also shown that for geometrical scattering case isotropic scattering leads to the conclusion of total internal reflection at the particle/medium interface.

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