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MCNPX User’s Manual
Version 2.6.0, April 2008
LA-CP-07-1473
GEOMETRY SPECIFICATION
Surface 1 describes a plane normal to the y-axis at y=3 with positive sense for all
points with y>3.
Example 2:
3
K/Y
0
0
2
0.25
1
Surface 3 is a cone whose vertex is at (x,y,z) = (0,0,2) and whose axis is parallel to
the y-axis. The tangent t of the opening angle of the cone is 0.5 (note that t2 is
entered) and only the positive (right hand) sheet of the cone is used. Points outside
the cone have a positive sense.
Example 3:
11
GQ
1
0
0.25
–12
0.75
0
–0.866
–2
3.464
39
This is a cylinder of radius 1 cm whose axis is in a plane normal to the x-axis at x=6,
displaced 2 cm from the x-axis and rotated 30 degrees about the x-axis off the y-axis
toward the z-axis. The sense is positive for points outside the cylinder. Such a
cylinder would be much easier to specify by first defining it in an auxiliary coordinate
system where it is symmetric about a coordinate axis and then using the TRn card
(see Section 5.2.3.7) to define the relation between the basic and auxiliary
coordinate systems. The input would then be
11 7 CX
*TR7
5.2.2.2
1
6
1
–1.732
0 30
60
AXISYMMETRIC SURFACES DEFINED BY POINTS
Form:
j
n
a
list
Table 5-5. Axisymmetric Surfaces
Input Parameter
Description
j
Surface number assigned by user.
Restriction: 1≤j≤99999
Restriction: 1≤j≤999 if j is the surface number of a repeated
structure or if surface j defines a cell that is transformed with TRCL.
See Section 5.2.3.5.
n
Transformation number on TR card.
If n is absent, then no coordinate transformation is specified.
a
The letter X, Y, or Z.
list
5-10
One to three coordinate pairs.
OFFICIAL USE ONLY
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MCNPX User’s Manual
April 2008