Dear Giovanni,
your question are far from beginner!
I'll try to provide some answers:
1) You surely have to add the EEDRAW contribution. It is related to all
situations where the energy is deposited in a point instead of along a
path. For instance: when an electron reaches the transport threshold, its
energy is deposited "on the spot" and EEDRAW is called. The same for part
of the energy deposits by low energy neutrons. Depending on your settings,
non-transported nuclear recolis might deposit at the production point.
2) Suppose you have an homogeneous region of thickness X and you wish to
see what is the energy deposition in N slices of this region, each with
thickness z. If z is smaller than the average step length of particles in
this region, one step will cover many slices. If you count the energy in
the middle of the step, you'll have spikes and holes. Instead, if you
deposit in all slices between Xtrack(0) and xtrack(ntrack) (same for yz),
you'll have energy in all slices. This is what is done in Fluka when
asking for "distributed USRBIN"
Of course, the necessity depends on the geometry and on the type of
information that you need.
3) the threshold issue for you is not on the pbar (for which threshold
must be zero.. rather for electron/photon transport. Again, it depends on
the granularity of your problem: you should set transport threshold such
as the range of particles at threshold is sizebly smaller than the
dimensions of your regions or scoring intervals. With the PRECISION
setting you have 100keV thresholds, which are usually ok for most
problems. (see
https://physics.nist.gov/PhysRefData/Star/Text/ESTAR.htmlfor range
tables).
Of course, lower thresholds mean larger CPU time.
I mentioned range, But, one more warning: if you have contiguous regions
with different materials, set equal thresholds in ENERGY, not in range,
unless you are far from the regions where you are scoring. Otherwise, the
equilibrium in the flow of electrons will be broken.
Hope this helps
( .. I did not look at your input and code..)
Paola
> Dear Fluka's experts,
> I am a beginner both in Fluka and MC simulations, thus the following
> questions. I have to simulate energy deposition of particles produced by
> annihilation of antiprotons. Our goal is rate production study of pi+- and
> pi0 from pbar annihilation. For our digitalization program we need the
> energy deposition and the position of the deposition for each particle
> step
> by step. After some studying, I decided to modify the mgdraw subroutine
> and
> to use it to get: the energy deposition via a sum over Dtrack, the
> position
> of the deposition that I put in the middle point of the step (compute with
> Xtrack, Ytrack and Ztrack), the id particle.
>
> Now, my doubts are three:
> 1) I am completely insecure about my procedure, I did not use EEDRAW, but
> I
> know that I have to add it, I just do not know what relation it has with
> the Dtrack energy deposition. Which is the difference between the energy
> deposition that I find in eedraw with RULL and Dtrack? Is it something
> related with the discrete energy deposition computation and the continuous
> one? At which position in the step do the position that I get with EEDRAW
> relate?
>
> 2) I am aware of many "warnings" provided by Fluka's experts in the
> Courses
> slides about energy deposition scoring, one example is "do NOT deposit the
> energy in the middle of the step, rather DISTRIBUTE it along the step". I
> do not understand this suggestion. How can I distribute the energy along
> the step (if the Dtrack energy I get is indeed that energy)?
>
> 3) Another warning was about delta ray production and thus I read
> something
> about threshold definition. Now, the pbar beam has an energy of 1KeV and I
> thought that for my scope PRECISIO is the default to use. I do not know if
> some EMFCUT has to be used to have some reliable results.
> Do I need to add some threshold in relation with our detector?
>
> I attach here the .inp file and the mymgdraw.
>
> Thank you in advance for any help and forgive me for the "beginner
> questions".
> Giovanni
>
> --
>
>
> Informativa sulla Privacy: http://www.unibs.it/node/8155
> <http://www.unibs.it/node/8155>
>
Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
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Received on Fri Mar 13 2020 - 21:16:11 CET