Re: particle distribution after the collimator

Dear Vitaly,
 I looked at your mgdraw.f, some comments:
* you have to define
      CHARACTER*8 MRGNAM, NRGNAM
* instead of
       IF ((MRGNAM.EQ."TARG".OR.MRGNAM.EQ."VOID").and.
     & JTRACK.EQ.1) THEN
you have to use
        IF ((MRGNAM.EQ."TARG".AND.NRGNAM.EQ."VOID").and.
    & JTRACK.EQ.1) THEN
if you want to score all particles leaving the target.
On the contrary if you are interested on the forward emission after the
target you have to define a tiny region at the end of the RCC ( for
example using XYP 9.995).

Ciao
Andrea

> 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 Thu Nov 12 2009 - 11:00:45 CET