Re: [fluka-discuss]: Alpha particles tracking

From: <me_at_marychin.org>
Date: Thu, 16 Mar 2017 10:55:13 +0800

Hi Jean-Emmanuel,

Be rest assured that the process in FLUKA is far less cryptic than
MCNP's PTRAC.

> get step by step where the energy deposition
#0 See $FLUPRO/flukapro/(TRACKR).

#1 The variable DTRACK is what you are looking for. It is an array, so
you need to loop over j=1,MTRACK.

#2 The point of interception should be at the earlier body of mgdraw.f,
that is, before any of the ENTRYs.

#3 The card for activating #2. For this part of mgdraw.f to be called
during FLUKA runs, you need to request so in your .inp with the USERDUMP
card with WHAT(3)=0. This request calls mgdraw at every single step of
every single particle, therefore extremely costly in terms of CPU. Just
a word of caution, as simulations may run till eternity e.g. with
electrons, with low-enough cuts and large-enough geometries.

The above is for energy deposition by continuous energy loss. For
discrete energy deposition events:
#1 The variable is RULL.
#2 The point of interception is mgdraw.f ENTRY ENDRAW.
#3 Activation is via the USERDUMP card, several options for WHAT(3) is
possible, at varying CPU costs. Pls refer to the manual and pick
whichever most economical for your problem.

Alternatively, both continuous and discrete energy depositions may be
accessed via comscw.f. RULL is the variable. comscw needs to be
activated with USERWEIG WHAT(6)>0 in .inp. In case you have multiple
USERWEIG-triggering scoring cards, you need to avoid double-counting
using ISCRNG and/or JSCRNG.

> the spectrum of the secondary electrons after every collision
#0 See $FLUPRO/flukapro/(GENSTK).
#1 The variable for recognising electrons is JTRACK=3. Secondaries are
accessed via KPART. The energy of each secondary is TKI. Both KPART and
TKI are arrays, to be looped over kp=1,Np.
#2 The point of interception is mgdraw.f ENTRY USDRAW.
#3 Activation is via the USERDUMP card, more than one option for WHAT(3)
is possible. Pls refer to the manual and pick whichever most economical.

:) mary

------------------------------------------------------------
 From: Jean-Emmanuel Groetz <jegroetz_at_univ-fcomte.fr>
Date: Tue, 14 Mar 2017 16:39:02 +0100

Hi,

I would like to track the energy deposition of alpha particles
(typically with 4-5 MeV) in water. Of course it could be done with
USRBIN, but this is not the initial objective.
This objective is to get step by step where the energy deposition is
done and the value of this energy deposition after every collision
along the path of the alpha particle.
Another objective is to get the spectrum of the secondary electrons
after every collision. In MCNPX or MCNP6, this kind of tracking could
be done with the PTRAC file, but I don't know how I could realize it
with a user file from fluka (mgdraw...).

Thank you for shedding light on this request.

Jean-Emmanuel

-- 
_______________________________________________
Jean-Emmanuel Groetz
Laboratoire Chrono-Environnement UMR CNRS 6249
Université de Franche-Comté
16 route de Gray
25030 Besançon Cedex
France
mailto : jegroetz_at_univ-fcomte.fr
tel : +33 (0) 3 81 66 65 07
fax : +33 (0) 3 81 66 65 22
http://chrono-environnement.univ-fcomte.fr/spip.php?article1537
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Received on Thu Mar 16 2017 - 05:02:54 CET

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