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Prague, Czech Republic

Braun H.H.,Paul Scherrer Institute | Fasso A.,ELI Beamlines | Ferrari A.,CERN | Jowett J.M.,CERN | And 3 more authors.
Physical Review Special Topics - Accelerators and Beams | Year: 2014

Reliable predictions of yields of nuclear fragments produced in electromagnetic dissociation and hadronic fragmentation of ion beams are of great practical importance in analyzing beam losses and interactions with the beam environment at the Large Hadron Collider (LHC) at CERN as well as for estimating radiation effects of galactic cosmic rays on the spacecraft crew and electronic equipment. The model for predicting the fragmentation of relativistic heavy ions is briefly described, and then applied to problems of relevance for LHC. The results are based on the fluka code, which includes electromagnetic dissociation physics and dpmjet-iii as hadronic event generator. We consider the interaction of fully stripped lead ions with nuclei in the energy range from about one hundred MeV to ultrarelativistic energies. The yields of fragments close in the mass and charge to initial ions are calculated. The approach under discussion provides a good overall description of Pb fragmentation data at 30 and 158A GeV as well as recent LHC data for sNN=2.76 TeV Pb-Pb interactions. Good agreement with the calculations in the framework of different models is found. This justifies application of the developed simulation technique both at the LHC injection energy of 177A GeV and at its collision energies of 1.38, 1.58, and 2.75A TeV, and gives confidence in the results obtained. © Published by the American Physical Society. Source

Bohlen T.T.,CERN | Cerutti F.,CERN | Chin M.P.W.,CERN | Fasso A.,ELI Beamlines | And 6 more authors.
Nuclear Data Sheets | Year: 2014

The FLUKA Monte Carlo code is used extensively at CERN for all beam-machine interactions, radioprotection calculations and facility design of forthcoming projects. Such needs require the code to be consistently reliable over the entire energy range (from MeV to TeV) for all projectiles (full suite of elementary particles and heavy ions). Outside CERN, among various applications worldwide, FLUKA serves as a core tool for the HIT and CNAO hadron-therapy facilities in Europe. Therefore, medical applications further impose stringent requirements in terms of reliability and predictive power, which demands constant refinement of sophisticated nuclear models and continuous code improvement. Some of the latest developments implemented in FLUKA are presented in this paper, with particular emphasis on issues and concerns pertaining to CERN and medical applications. © 2014 Elsevier Inc. Source

Mazuritskiy M.,Southern Federal University | Lerer A.,Southern Federal University | Ezovtsov A.,Southern Federal University | Kalinchenko G.,ELI Beamlines
Progress in Electromagnetics Research Symposium | Year: 2015

The features of soft X-ray fluorescence spectra of radiation propagating inside micro-channel plates have been studied in the framework of wave approximation. X-ray and fluorescence yield due to the grazing incidence reflection phenomenon have been investigated with respect to the geometry of channel walls. We researched experimental spectra collected at the exit of micro-capillaries under total X-ray reflection condition and supported them with theoretical calculations taking into account a surface transition layer at waveguide surface. It was shown that the wave penetrating through cladding material substantially modifies the wave field near the waveguide surface. It results in a significant increase of total energy flux inside guiding layer and leads to additional spatial modulation of the electromagnetic field. Diffraction phenomena at the exit of a hollow X-ray waveguide (with real and imaginary parts of permittivity) were investigated using the model of Fraunhofer diffraction of waves at far zone. Source

Lerer A.M.,Southern Federal University | Timoshenko P.E.,Southern Federal University | Kalinchenko G.A.,ELI Beamlines | Kaidashev E.M.,Southern Federal University | Puzanov A.S.,Southern Federal University
Progress in Electromagnetics Research Symposium | Year: 2015

The electromagnetic waves propagation in a two-dimensional periodic array of zinc oxide nanowaveguides covered with a thin metal film is solved by the separation of variables method in cylindrical coordinates. The numerical results obtained by our method are in good agreement with the ones computed by the commercial software COMSOL Multiphysics™ over all optical range and have minor deviations for the wavelength range close to the critical wavelength. Resonances located at the amplitude-frequency characteristics of optical nanoantennas may be interpreted as resonances of circular bilayer nanowaveguide segments with the ZnO core covered with thin metal shell. The results may also be used to predict the resonant wavelength of two-dimensional periodic arrays of ZnO nanorods coated with a thin metal layer and grown on a dielectric substrate. Source

Kalinchenko G.,ELI Beamlines | Vyhlidka S.,ELI Beamlines | Vyhlidka S.,Charles University | Kramer D.,ELI Beamlines | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

A diffraction grating based on all-dielectric multi-layer structure is designed for compression of ultrafast pulses with spectrum centered at 900 nm. The grating at Littrow angle with an out-of-plane configuration shows more than 96% efficiency over the reflective band of 100 nm for the angle of incidence 41 degrees. We suggest grating grooves and the very first layer under the grooves to be made of fused silica. Reflective mirror under corrugated layer is designed as a stock of three types of dielectric nanolayers. Tolerances for groove depth and angle of incidence are estimated and, optimal duty-cycle parameter is found out. Electric field distribution inside of the grating is also numerically studied. The model is simulated by two methods: numerical Fourier Modal Method in LightTrans Virtual Lab and semianalytical Volume Integral Equation Method. The results obtained by both methods show an excellent agreement. © 2015 SPIE. Source

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