Re: FW: Lack of USRBDX Results

From: Stefan Roesler <>
Date: Fri, 24 Aug 2012 18:10:42 +0200

Hi Matthias and Aiveen

Joachim has forwarded me your input. Apart from the additional STOP card
before the scoring that you should remove it is lack of statistics that
you don't get any fluence. The surface at which you score is tiny, at
quite some distance to the copper piece and beam is incident under an
angle and will never arrive itself at the scoring surface.

I suggest that you extend your USRBIN to include the region in which you
score to convince yourself where the particles go. For example, if you
shift your beam to x=y=0, remove the angle with z and set COPPER to
VACUUM you will see it in the USRBDX scoring.

Please note that the region parameters in USRBDX are 'from region What(4)
to region What(5)'. I think in your input What(4) is the more downstream
region. No problem for a two-way scoring if you are aware of it.


> -----Original Message-----
> From: [] On Behalf Of Scholz, Matthias
> Sent: 21 August 2012 15:43
> To:
> Cc: Aiveen Finn
> Subject: Lack of USRBDX Results
> Dear Fluka Experts and Users,
> I am using Fluka to simulate what happens in a collimator of an FEL and wish to use USRBDX.
> However I have problems with USRBDX. It either won't produce results, just blank files
> or else 4 columns full of zeroes except for maybe two actual numbers.
> I am wondering whether it's how I go about making the areas that will be hence defined in
> the BDX card however I have edited these settings with little change in the
> results. Originally, I made a 'bullseye' shape of vacuums in the area I want to
> measure the particles. Furthermore I have edited the material (eg to helium) of the
> vacuums to see if this helps and it does give more results presumably as the
> electrons interact with the helium, however in reality this data is not what
> I need. I require the amount of energy/number of particles entering and
> leaving certain =3D parts of the 'bullseye'.
> Thank you in advance.
> Best wishes,
> Aiveen Finn
Received on Sun Aug 26 2012 - 15:34:23 CEST

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