I should clarify what I said about the default (triangular) vertex
distribution. The triangular distribution works in two steps:
1) Two random numbers, z and rho, are picked. z lies (randomly) within
-20cm < z < +20cm. rho lies (randomly) within 0 < rho < 1. After
picking such (random) z and rho values, the following value is computed:
value = ((1.0 - abs(z)/20.0) > rho)
If value == 1 (i.e. if (1.0 - abs(z)/20.0) is indeed greater than
rho), then program execution goes on to step 2); otherwise, step 1) is
repeated over again.
2) A random value for rho between 0 < rho < 0.5mm is picked. Also a
random value for theta between 0 < theta < 2*pi is picked. Then the
(cylindrical) vertex point (rho, theta, z) is assigned, where the z
value comes from 1).
Thus, 1) incorporates the triangular probability distribution portion; 2)
incorporates choosing the actual vertex point.
Aaron
On Wed, 11 Sep 2002, Tancredi Botto wrote:
> >
> > The most realistic vertex method that the Monte Carlo currently has is
> > vertex style 0. This style has an extended target of total length 40cm
> > and has a triangular distribution in (cylindrical) rho about this length,
> > out to a maximum of 0.5mm, centered in the middle of the target.
> >
>
> I am not sure I understand what you mean. The triangular distribution is
> only a function of z, the cell length
>
> rho(x) = rho(0) * ( 1 - |z|/L)
>
> where 2L is the cell lenght (40 cm). rho(0) can be found from the total
> (atomic) flow divided by the total cell conductance (you have to add
> the equal contributions from the two hlves, each of length L, diameter d)
> There is no radial dependence.
>
> Cheers,
> tancredi
>
>
>
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