particle distribution after the collimator

From: Gostishchev, Vitaliy Dr. <>
Date: Wed, 11 Nov 2009 11:08:06 +0100

Dear FLUKA experts,

Recently I asked the FLUKA community about the way to obtain the
particle distribution after the collimators.

...I would kindly ask you to help me in solution of one problem. We are
going to calculate the passage of the particles through the graphite
collimators in details. This means that we want to know the change of
original particle distribution including particles going directly
through the graphite. There is a certain particle distribution before
the collimator. Then the particles pass mostly through the collimator
slit but part of them pass directly through the collimator material.
Graphite is not so effective as iron in sense of particle cutting. The
radiation length for graphite is about 30 cm only. Therefore, we need
longer collimators but, unfortunately, we have not enough space for
them. We are interested in particles which can come to the transfer beam
acceptance together with antiprotons, for example, pions. Pions have
similar rigidity in our case and theoretically can be transport to the
ring and make some harm there. Could you recommend some proper way to
obtain such a particle distribution after collimator. Do we need some
additional code? The idea is to have a particle distribution before and
after collimator in order to understand how many particles can come to
the septum magnet of the following storage ring. It gives us an
information about possible problems...

There were several useful recommendations but, unfortunately, I didn't
solve the problem up to now. I tried to use the MGDRAW subroutine and
wrote some lines in mgdraw.f (namely, in entry BXDRAW). I'm not sure
that this is correct and the best variant. In addition, maybe something
wrong with my input file. Nevertheless, there are some errors occurred
during compilation. Maybe I'm using the CALL GEOR2N in wrong way because
there are some errors due to different type of variables. I didn't
understand how it really works.

I appreciate any help. Thank you in advance.

Best regards,
Vitaliy Gostishchev

p.s. In the attachment you can find my input and the modified MGDRAW.F
files. <<distribv1.inp>> <<mgdraw.f>>

Received on Wed Nov 11 2009 - 11:53:21 CET

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