Energy loss distributions of 7 TeV protons channeled in a bent silicon crystals

The energy loss distributions of relativistic protons axially channeled through the bent <100> Si crystals, with the constant curvature radius, R = 50 m, are studied here. The proton energy is 7 TeV and the thickness of the crystal is varied from 1 mm to 5 mm, which corresponds to the reduced crystal thickness, L, from 2.1 to 10.6, respectively. The proton energy was chosen in accordance with the large hadron collider project, at the European Organization for Nuclear Research, in Geneva, Switzerland. The energy loss distributions of the channeled protons were generated by the computer simulation method using the numerical solution of the proton equations of motion in the transverse plane. Dispersion of the proton scattering angle caused by its collisions with the crystal’s electrons was taken into account. [Projekat Ministarstva nauke Republike Srbije, br. III 45006

Electrochromic Nickel Oxide Thin Films for Solar Light Modulation

Nickel oxide (NiO

Influence of nuclear multiple scattering on axially channeled protons in a bent crystal

The influence of nuclear multiple scattering on axially channeled protons with an energy of 7 TeV through a bent Si crystal, is presented in this paper. The aims of the investigation are the processes correlated to the axial channeling, such as dechanneling, angular distributions and energy loss distribution. The data for these processes are generated via the numerical solution of the proton equations of motion in the transverse plane and the computer simulation method. In the simulations, the crystal thickness is varied from 1 to 5 mm while the bending angle is varied from 0 to 20 μrad. The increasing of the transverse energy of axially channeled protons is due to its multiple scattering by atomic strings and the bending dechanneling mechanism. The analysis of the generated data shows that in the cases we are considering, the dechanneling function, the energy loss spectra, and the angular distributions do not undergo to any significant changes when the effect of nuclear multiple scattering is included in the ion-atom interactions. © 2018, Vinca Inst Nuclear Sci. All rights reserved

Energy loss distributions of 7 TeV protons axially channeled in the bent LT 1 1 0 GT Si crystal

In this article, the energy loss distributions of relativistic protons axially channeled in the bent LT 1 1 0 GT Si crystal are studied. The crystal thickness is equal to 1 mm, which corresponds to the reduced crystal thickness, Lambda, equal to 1.22, whereas the bending angle, alpha, was varied from 0 to 30 mu rad. The proton energy of 7 TeV was chosen in accordance with the concept of using the bent crystals as a tool for selective deflection of the beam halo particles from the LUA9 experiment at LHC. For the continuum interaction potential of the proton and the crystal the Molieres expression was used and the energy loss of a proton was calculated by applying the trajectory dependent stopping power model. Further, the uncertainness of the scattering angle of the proton caused by its collisions with the electrons of the crystal and the divergence of the proton beam were taken into account. The energy loss distribution of the channeled protons was obtained via the numerical solution of the proton equations of motion in the transverse plane and the computer simulation method. The analysis of the obtained theoretical data shows that the shape of the energy loss distribution strongly depends on the horizontal or vertical direction of the curvature of the crystal. The number of dechanneled protons as a function of the bending angle also strongly depends on the direction of the crystals curvature. As a result, the dechanneling rates and ranges, obtained from the Gompertz type sigmoidal fitting functions, have different sets of values for different bending orientations. We have also studied the influence of the proton beam divergence on the energy loss distribution of channeled protons. (C) 2016 Elsevier B.V. All rights reserved

Dimerization of magnetic lattice influenced by an ensemble of neutral magnetic dipoles

We have studied bound states of a neutral non-relativistic spin-(1/2) particle in a one-dimensional system of magnetic barriers and magnetic delta-functions. If such non-rigid lattice is a host lattice of an ensemble of non-interacting neutral particles, this structure is unstable in dimerizations of the Peierls type

Influence of nuclear multiple scattering on axially channeled protons in a bent crystal

The influence of nuclear multiple scattering on axially channeled protons with an energy of 7 TeV through a bent Si crystal, is presented in this paper. The aims of the investigation are the processes correlated to the axial channeling, such as dechanneling, angular distributions and energy loss distribution. The data for these processes are generated via the numerical solution of the proton equations of motion in the transverse plane and the computer simulation method. In the simulations, the crystal thickness is varied from 1 to 5 mm while the bending angle is varied from 0 to 20 mrad. The increasing of the transverse energy of axially channeled protons is due to its multiple scattering by atomic strings and the bending dechanneling mechanism. The analysis of the generated data shows that in the cases we are considering, the dechanneling function, the energy loss spectra, and the angular distributions do not undergo to any significant changes when the effect of nuclear multiple scattering is included in the ion-atom interactions

Angular distributions of 7 TeV protons axially channeled through the thin bent (100) Si crystal

We have studied theoretically angular distributions of relativistic protons axially channeled through the thin bent LT 100 GT Si crystal. The proton energy is 7 TeV, the thickness of the crystal is 1 mm, which corresponds to the reduced crystal thickness, Lambda, equal to 2.1, while the bending angle, alpha, is varied from 0.002 to 0.020 mrad. The angular distributions of axially channeled protons are generated by the computer simulation method using the numerical solution of the ion equations of motion, with the Lindhards expression for the continuum interaction potential of the ion and the crystal. Uncertainness of the scattering angle of the proton caused by its collisions with the electrons of the crystal and proton (electronic) energy loss are taken into account. The results of the analysis show that the two additional maxima appear in the angular distributions, for the bending angles alpha LT = 0.006 mrad. They originate from four areas in the impact parameter plane located in between atomic strings defining the channel that correspond to the saddle points of the continuum potential. The obtained deflection efficiency curve has an inflection point, which can be attributed to the disappearing of the two additional maxima in the angular distribution. We have also studied the dependence of the deflection efficiency on the length of the crystal when the deflection angle is equal to 0.1 mrad, regarding the possible application of the crystal channeling for halo collimation of the proton beam in the Large Hadron Collider (LHC) project, at the European Organization for Nuclear Research (CERN). (c) 2005 Elsevier B.V. All rights reserved

Angular distributions of relativistic ions channeled in the bent 〈100〉 Si crystals

The angular distributions of relativistic protons channeled in the bent 〈100〉 Si crystals are considered. The ion energy is 7 TeV, the radius of curvature of the crystal is 49.8 m and the crystal thickness is varied from 0.1 to 0.5 cm (before bending), corresponding to the bending angle range from 0.02 to 0.1 mrad. The crystal thickness range under consideration corresponds to the reduced crystal thickness range from 2.1 to 10.35. The angular distributions of transmitted protons were generated by the computer simulation method using the numerical solution of the ion equations of motion, with the Lindhard's expression for the continuum interaction potential of the ion and the crystal. The results of the analysis show that the angular distribution has a periodic behavior for the reduced crystal thickness, Λ, smaller than about 5. For variable Λ larger than 5 the angular distribution is “frozen”, i.e. its shape does not change, and this is accompanied by a slow decrease of the number of transmitted ions as Λ increases

Energy loss distributions of relativistic protons axially channeled in a bent silicon crystal

A detailed study of the energy loss distributions of the relativistic protons axially channeled in the bent LT 100 GT Si crystals is presented in this work. The bending angle was varied from 0 to 20 mu rad, while the crystal thickness was equal to 1 mm. The proton energy was chosen to be 7 TeV in accordance with the Large Hadron Collider (LHC) project, at the European Organization for Nuclear Research (CERN), in Geneva, Switzerland. The energy loss distributions of the channeled protons were generated using the numerical solution of the proton equations of motion in the transverse plane and the computer simulation method. An accurate energy loss model was used, which takes into account the trajectory dependence of the energy loss of protons during their motion through the crystal channels. Further, the dispersion of the protons scattering angle caused by its collisions with the electrons of the crystal and the divergence of the proton beam were taken into account. The calculated dependence of the number of dechanneled protons on the bending angle was excellently fitted by the Gompertz type dechanneling function. (C) 2013 Elsevier B.V. All rights reserved

Electrochromism in tungsten oxide thin films prepared by chemical bath deposition

Tungsten oxide (WO3) thin films were prepared by a simple, economical, chemical bath deposition method onto fluorine doped tin oxide (FTO) coated glass substrates. The electrochemical properties of the films were characterized by cyclic voltammetry. The obtained films exhibited electrochromism, changing color from initially colorless to deep blue, and back to colorless. Visible transmittance spectra of (WO3) films were recorded in-situ in their both, bleached and colored states. From those spectra, absorption coefficient (a) and the optical energy gaps were evaluated. The dependence of the optical density on the charge density was examined and the coloration efficiency (h) was calculated to be 22.11 cm2 C-1. The response times of the coloring and bleaching to an abrupt potential change from -2.5 V to +2.5 V and reverse, were found to be 9.3 and 1.2 s respectively. The maximum light intensity modulation ability of the films, when the AM1.5 spectrum is taken as an input, was calculated to be about 50 %