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Coloring Cells by Value
Visualization of a spatially dependent quantity, such as a particle flux or dose rate, is extremely useful for the understanding of a radiation transport problem. A color coding scheme, where each color represents a data value or range of values, is often the most useful method for displaying the data. Combining the color coded data representation with some or all of the problem geometry enhances the visualization.
Prior to the introduction of the grid tally, data from MCNP runs was restricted to tallies on cells and surfaces. In Moritz, geometry cells can be colored according to a value associated with each cell. The color is assigned from a mapping that goes from blue to cyan to green to orange to red (or vice versa) according to the value or its logarithm. The floor planand a vertical section
show a examples of geometry cells in a 2D plot colored by the dose equivalent rate that was calculated with MCNPX. In the 3D plot
, the concrete cells are drawn in the wire frame mode that shows their edges. Cells that do not have a value assigned retain their original color, such as the grey concrete, brown dirt, and white void cells in the Figures.
Geometry cells may be assigned a value to be used in setting their color. It is not necessary to assign a value to all cells. Those that do not have a value retain the color they would have otherwise. The assignment is made by reading a command (.sab) file contain a list of cell number-value pairs following a Value Cell command and terminating with a 0. For example,
assigns a value of 0.00015 to cell 1, etc. The scaling limits are initially set to the range of values read in. These limits and whether logarithmic scaling is used is currently set on the Color Legend dialog.Value Cell
1 1.5e-4
2 0.034
3 1.789
0
.
There are several drawbacks to the cell-based method. Preparation of the file of (cell number, value) pairs requires pulling the numbers out of MCNP (or MCNPX) output file. That task requires either tedious editing or the writing of a program to parse the output file. A smooth variation of the color coding may require more cells than would otherwise be used, which in turn increases the computation time. The problem of inadequate spatial refinement is exacerbated if mesh based weight windows are used, rather than cell based weight windows or importance splitting.
 White Rock Science http://www.whiterockscience.com/wrs.html 505 672 1105 |
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and a vertical
section 
show a examples of
geometry cells in a 2D
plot colored by the dose equivalent rate that was calculated with
MCNPX. In the 3D plot 
, the
concrete
cells are drawn in the wire frame mode that shows their edges. Cells
that
do not have a value assigned retain their original color, such as the
grey
concrete, brown dirt, and white void cells in the Figures.