X-Ray Microanalysis with Penelope

2001 ◽  
Vol 7 (S2) ◽  
pp. 688-689
Author(s):  
F. Salvat ◽  
L. Sorbier ◽  
X. Llovet ◽  
E. Acosta

Monte Carlo simulation is a suitable tool for the numerical generation of x-ray spectra by electron beams and, more specifically, for the quantification in electron probe microanalysis (EPMA). in this communication we describe the application of the general-purpose code PENELOPE to EPMA. This code simulates electron-photon showers in complex material structures consisting of homogeneous regions of arbitrary composition limited by quadric surfaces. It is devised to cover a wide energy range (from ∼500 eV to about 1 GeV). The interaction models implemented in PENELOPE are based on the most reliable information available. They combine results from first principles calculations (this is the case, e.g., for electron elastic scattering, photon Compton scattering), semiempirical models (in electron inelastic scattering) and information from evaluated data bases. to facilitate the random sampling, the cross sections of various interaction mechanisms are described through analytical expressions, which are adjusted to yield accurate values of relevant transport properties (mass attenuation coefficients, transport mean free paths, stopping powers, . . . ).

2021 ◽  
Vol 9 ◽  
Author(s):  
Makoto Asai ◽  
Miguel A. Cortés-Giraldo ◽  
Vicent Giménez-Alventosa ◽  
Vicent Giménez Gómez ◽  
Francesc Salvat

A translation of the penelope physics subroutines to C++, designed as an extension of the Geant4 toolkit, is presented. The Fortran code system penelope performs Monte Carlo simulation of coupled electron-photon transport in arbitrary materials for a wide energy range, nominally from 50 eV up to 1 GeV. Penelope implements the most reliable interaction models that are currently available, limited only by the required generality of the code. In addition, the transport of electrons and positrons is simulated by means of an elaborate class II scheme in which hard interactions (involving deflection angles or energy transfers larger than pre-defined cutoffs) are simulated from the associated restricted differential cross sections. After a brief description of the interaction models adopted for photons and electrons/positrons, we describe the details of the class-II algorithm used for tracking electrons and positrons. The C++ classes are adapted to the specific code structure of Geant4. They provide a complete description of the interactions and transport mechanics of electrons/positrons and photons in arbitrary materials, which can be activated from the G4ProcessManager to produce simulation results equivalent to those from the original penelope programs. The combined code, named PenG4, benefits from the multi-threading capabilities and advanced geometry and statistical tools of Geant4.


1990 ◽  
Vol 34 ◽  
pp. 337-347
Author(s):  
C. Rossington ◽  
J. Jaklevic ◽  
J. Reid ◽  
C. Haber ◽  
H. Spieler

Many of the scientific programs proposed for implementation at existing and future synchrotron radiation sources involve measurement of the spatial distribution of transmitted or diffracted x-ray beams. The design of a general purpose position-sensitive detector for use in such experiments must address several conflicting requirements. Ideally, such a detector would meet the following criteria: high detection efficiency over a wide energy range, large dynamic range in measured photon intensities and response to a wide range of measurement intervals. Existing detector systems only partially meet these requirements, although much work has gone into improving the current technology.


2013 ◽  
Vol 21 (1) ◽  
pp. 273-279 ◽  
Author(s):  
L. Xue ◽  
R. Reininger ◽  
Y.-Q. Wu ◽  
Y. Zou ◽  
Z.-M. Xu ◽  
...  

A new ultrahigh-energy-resolution and wide-energy-range soft X-ray beamline has been designed and is under construction at the Shanghai Synchrotron Radiation Facility. The beamline has two branches: one dedicated to angle-resolved photoemission spectroscopy (ARPES) and the other to photoelectron emission microscopy (PEEM). The two branches share the same plane-grating monochromator, which is equipped with four variable-line-spacing gratings and covers the 20–2000 eV energy range. Two elliptically polarized undulators are employed to provide photons with variable polarization, linear in every inclination and circular. The expected energy resolution is approximately 10 meV at 1000 eV with a flux of more than 3 × 1010 photons s−1at the ARPES sample positions. The refocusing of both branches is based on Kirkpatrick–Baez pairs. The expected spot sizes when using a 10 µm exit slit are 15 µm × 5 µm (horizontal × vertical FWHM) at the ARPES station and 10 µm × 5 µm (horizontal × vertical FWHM) at the PEEM station. The use of plane optical elements upstream of the exit slit, a variable-line-spacing grating and a pre-mirror in the monochromator that allows the influence of the thermal deformation to be eliminated are essential for achieving the ultrahigh-energy resolution.


1998 ◽  
Vol 5 (3) ◽  
pp. 989-991 ◽  
Author(s):  
Andrei Rogalev ◽  
Vincent Gotte ◽  
Jose´ Goulon ◽  
Christophe Gauthier ◽  
Joel Chavanne ◽  
...  

The first experimental applications of the undulator gap-scan technique in X-ray absorption spectroscopy are reported. The key advantage of this method is that during EXAFS scans the undulator is permanently tuned to the maximum of its emission peak in order to maximize the photon statistics. In X-MCD or spin-polarized EXAFS studies with a helical undulator of the Helios type, the polarization rate can also be kept almost constant over a wide energy range.


1996 ◽  
Vol 165 ◽  
pp. 321-331
Author(s):  
H. Inoue

ASCA, the fourth Japanese X-ray astronomy satellite, was launched by the Institute of Space and Astronautical Science (ISAS) on 1993 February 20. ASCA is designed to be a high-capability X-ray observatory (Tanaka et al. 1994). It is equipped with nested thin-foil mirrors which provide a large effective area over a wide energy range from 0.5 to 10 keV. Two different types of detectors, CCD cameras (SIS) and imaging gas scintillation proportional counters (GIS) are employed as the focal plane instruments.


2015 ◽  
Vol 22 (2) ◽  
pp. 328-335 ◽  
Author(s):  
Chaofan Xue ◽  
Yanqing Wu ◽  
Ying Zou ◽  
Lian Xue ◽  
Yong Wang ◽  
...  

A new monochromator called an extra-focus constant-included-angle varied-line-spacing (VLS) cylindrical-grating monochromator (extra-focus CIA-VCGM) is described. This monochromator is based on the Hettrick–Underwood scheme where the plane VLS grating is replaced by a cylindrical one in order to zero the defocus at three reference photon energies in the vacuum-ultraviolet range. It has a simple mechanical structure and a fixed focus spot with high performance over a wide energy range. Furthermore, its mechanical compatibility with a standard VLS plane-grating monochromator allows convenient extension into the soft-X-ray range.


2014 ◽  
Vol 68 (6) ◽  
Author(s):  
Martina C. Fuss ◽  
Ana G. Sanz ◽  
Francisco Blanco ◽  
Paulo Limão-Vieira ◽  
Michael J. Brunger ◽  
...  

2004 ◽  
Vol 82 (4) ◽  
pp. 277-289 ◽  
Author(s):  
G El Machtoub

We present explicit calculations of channel-specific dielectronic recombination cross sections for hydrogen-like germanium, Ge(XXXII); selenium, Se(XXXIV); and krypton, Kr(XXXVI). The convoluted cross sections characterize K-shell emission spectra over a wide energy range where contributions from high-n (n = 2–10), satellite lines are included. The high-n contributions presented are important for better diagnostics in the domain of high-temperature plasmas. PACS Nos.: 32.30.Rj, 32.70.Rm, 34.70.te


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