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Title: RYLLA. [X-ray transport code]

This paper describes a computer code, RYLLA, which models the deposition of x-rays into thin metal slabs, and transports the resulting photoelectrons, finding the distribution of electrons leaving the slab from both the front and back surfaces. The slab must be homogeneous, but can contain a mixture of up to 5 different elements. Due to the short electron mean free path at low electron energies, RYLLA should be used only for studying thin slabs, roughly < 100 mg/cm/sup 2/ for low Z metals, and < 10 mg/cm/sup 2/ for high Z metals. X-ray energies should be in the range of 1 to 150 keV, as they are deposited only via photoionization and Compton scattering processes. Following photoionization, a hole exists in the electron cloud of the absorbing atom. This fills either by Auger or fluoresence, resulting in lower energy holes which are also filled. Fluoresence photons are transported and absorbed in the same manner as the primary photons, except that they are isotropically produced. Once all photons have been transported and absorbed, and all holes have been filled, a space- and energy-dependent electron source spectrum has been obtained. This is used in a discrete ordinate expansion solution of the 1-Dmore » transport equation, which gives the output electron spectra at the two slab surfaces. This paper discusses both the physics and coding of RYLLA. Examples of user input are given, as are some comparisons with other codes.« less
Authors:
Publication Date:
OSTI Identifier:
5975143
Report Number(s):
UCID-19813
ON: DE83013704
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Technical Report
Research Org:
Lawrence Livermore National Lab., CA (USA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; COMPUTER CODES; R CODES; METALS; PHOTON TRANSPORT; X RADIATION; TRANSMISSION; ABSORPTION; ENERGY ABSORPTION; KEV RANGE 01-10; KEV RANGE 10-100; ONE-DIMENSIONAL CALCULATIONS; PHOTOELECTRIC EMISSION; SLABS; ELECTROMAGNETIC RADIATION; ELECTRON EMISSION; ELEMENTS; EMISSION; ENERGY RANGE; IONIZING RADIATIONS; KEV RANGE; NEUTRAL-PARTICLE TRANSPORT; RADIATION TRANSPORT; RADIATIONS 654001* -- Radiation & Shielding Physics-- Radiation Physics, Shielding Calculations & Experiments; 990200 -- Mathematics & Computers