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- Thread starter candice_84
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Astronuc

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One is simply integration over all 'directions'. 4π is just the total solid angle, which represents all directions/orientations.

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candice_84

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2pi = 360 which is enough.

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Astronuc

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2pi = 360 which is enough.

2 pi in 2D, not 3D.

In 3D, 2 pi is half the solid angle encompassed by a sphere, i.e. hemisphere.

Think - the area of a sphere is 4pi r

Note, when one refers to

[tex]\phi(r,E,\vec{\Omega})[/tex]

one is referring to the angular flux in n/cm2-s-(unit E)-steradian.

Integrating over the solid angle gives the 'scalar' flux.

http://en.wikipedia.org/wiki/Neutron_transport

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candice_84

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solid angle is a volume?

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Astronuc

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No solid angle is the solid angle, like angle is angle in 2D. The 4π (steradians) solid angle is the 3D analog to 2π radians in 2D.solid angle is a volume?

The total solid angle would be the area of a sphere divided by r

http://en.wikipedia.org/wiki/Steradian

http://en.wikipedia.org/wiki/Solid_angle

http://mathworld.wolfram.com/SolidAngle.html

http://mathworld.wolfram.com/Radian.html

http://mathworld.wolfram.com/Angle.html

- #7

candice_84

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This integration is only correct if we assume neutrons are produce and move uniformly. Its better to not convert it to scalar format, am i right?

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