From 7dfcc480ba1e19bd3232349fc733caef94034292 Mon Sep 17 00:00:00 2001
From: stainer_t <thomas.stainer@oecd-nea.org>
Date: Mon, 8 Sep 2025 13:48:49 +0200
Subject: Initial commit from Polytechnique Montreal

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+\subsection{MATXS7A microscopic cross-section examples}\label{sect:ExMATXS}
+
+The test cases we will consider here use the \moc{LIB:} module to specify that
+the cross sections will be taken from a MATXS7A 69 groups microscopic
+cross-sections library. We will assume that this library is located in file
+\moc{MATXS7A}.
+
+\subsubsection{\tst(TCXA01) -- The Mosteller benchmark.} 
+              
+The typical input data required to analyze this
+benchmark\cite{Mostel} with DRAGON is of the form:
+
+\listing{TCXA01.x2m}
+
+\vskip 0.3cm
+
+The input deck begins with declarations for the linked lists and the interface
+files and the various modules used for this DRAGON execution. Any word not declared is considered as
+a keyword.
+
+The {\tt LIB:} module is used to interpolate the microscopic cross sections
+in absolute temperature and dilution and to produce group-ordered macroscopic
+cross sections. We use the MATXS format 69 groups microscopic cross
+section library named {\tt 'MATXS7A'}.\cite{MATXS7A}.
+Each mixture at a given absolute temperature (in Kelvin) is defined in terms
+of MATXS isotope names ({\tt U235, U238, O16,} etc.). In this case, the
+number density (in $10^{24}$ particules per cubic centimeter) for each isotope is
+provided. Resonant region indices and the type of thermal scattering
+approximation used with the 42 thermal groups (free gas or H$_2$O molecular
+model) is also specified. Only MATXS type libraries require the thermalization
+model to be set.
+
+
+The {\tt GEO:} module is used to define the geometry. Here two types of geometry are considered,
+\moc{MOSTELA} a 1--D annular geometry and \moc{MOSTELC} a 2--D Cartesian geometry. These geometries
+are defined before knowing the type of discretization or numerical treatment that will follow.
+For \moc{MOSTELA} the first line indicates that the geometry has circular boundaries and that it
+contains three concentric annular subregions. The boundary conditions (reflection), the annular
+radii and the mixture index corresponding to each region of the cell are
+given successively. For \moc{MOSTELC} the first line indicates that this geometry has 2--D
+Cartesian boundaries containing three subregions, two of which are annular. The boundary conditions
+(reflection on each side), the annular radii, the external side widths and the mixture index
+corresponding to each region of the cell are given successively.
+
+Four cases are then considered. First we will analyse the annular geometry using the \moc{SYBILT:} module for flux
+calculation. The \moc{DISCR} and dds{tracking} structures are thereby
+generated. The {\tt SHI:} module uses microscopic cross section data contained in the
+\moc{LIBRARY} and tracking information contained in {\tt 'DISCR'} and {\tt 'TRACKS'} in order to
+compute the actual dilution of each resonant isotope ({\tt U235} and {\tt U238}) and to perform a
+new interpolation in the MATXS file. Dilutions are only computed for the energy groups with resonance data present on the library; the other groups are assumed to stay at infinite dilution.
+
+For the second case we will analyse the Cartesian geometry using the again the
+\moc{SYBILT:} tracking module for self shielding calculations and the \moc{SYBILT:} module for
+flux calculation. The \moc{DISCR} and \dds{tracking} structures are thereby generated.
+
+Four cases are then considered. First we will analyse the annular geometry using the {\tt SYBILT:}
+tracking module allows the geometry named {\tt 'MOSTEL'} to be discretized by the full CP tracking
+algorithm. A new tracking file (sequential binary) is created and named {\tt 'TRACKS'}, together
+with a
+\dds{tracking}l structure named {\tt 'DISCR'}. A periodic tracking (with 12
+angles and 20.0 tracks per cm) is considered here.
+
+The {\tt ASM:} module uses macroscopic cross section data contained in the
+embedded \dds{macrolib} of {\tt 'LIBRARY'} and tracking information contained
+in {\tt 'DISCR'} and {\tt 'TRACKS'} in order to compute the reduced and
+scattering modified collision probability matrices for each of the 69 energy
+groups. We have not used the important capability of DRAGON to use a different
+tracking to perform self-shielding and flux calculations.
+
+
+The {\tt FLU:} module uses macroscopic cross section data contained in {\tt
+'LIBRARY'} (recovered from the dependency tree) and CPs contained in {\tt
+'CP'} in order to compute the neutron flux for each of the 69 energy groups. The
+transport equation is solved for the effective multiplication factor
+without buckling or leakage model.
+
+
+Next, the {\tt EDI:} module performs spatial homogenization (the cross sections
+are smeared over the complete cell) and coarse energy group condensation. The
+first coarse energy group contains the micro-groups 1 to 27; the second coarse
+energy group contains the remaining micro-groups. 
+
+\eject
-- 
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