From: Santana, Mario <msantana_at_slac.stanford.edu>

Date: Sun, 16 Jan 2011 10:45:48 -0800

Date: Sun, 16 Jan 2011 10:45:48 -0800

Hamideh,

Actually, if you want uniform sampling in 2-D cylindrical coordinates

you need to do the following:

r =3D UBEAM * SQRT(FLRNDM(dummy))

without the SQRT you would be giving more weight to the positions closer

to the beam axis.

Mario

On Jan 16, 2011, at 1:28 AM, Hamideh Jalali wrote:

*> Dear FLUKA experts
*

*>
*

*> I'm going to define a circular beam in x-y plane ( a beam which
*

*> travels around a circle of radius r and center (0,0,0)). Is it correct
*

*> if I follow these steps:
*

*>
*

*> In BEAMPOS card:
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*> WHAT(1)-WHAT(3):x,y,z coordinates of the center of the
*

*> circle(XBEAM-YBEAM-ZBEAM)
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*> WHAT(4): radius of the circle (UBEAM)
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*>
*

*> Then I modify source.f by adding these command:
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*>
*

*> r =3D UBEAM * (FLRNDM(dummy)
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*> alpha =3D 2 * PI* (FLRNDM(dummy))
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*>
*

*>
*

*> XFLK (NPFLKA) =3D XBEAM + r * COS(alpha)
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*> YFLK (NPFLKA) =3D YBEAM + r * SIN(alpha)
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*> ZFLK (NPFLKA) =3D ZBEAM
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*>
*

*> I would be grateful for your help.
*

*> Hamideh
*

*>
*

Received on Sun Jan 16 2011 - 20:39:56 CET

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