[fluka-discuss]: RE: Computing the distribution of an isotope over the entire geometry

From: Anton Lechner <Anton.Lechner_at_cern.ch>
Date: Fri, 21 Feb 2014 14:07:55 +0000

Sorry, there was a small typo in my previous Email: calls to USRRNC are activated via WHAT(5) and not WHAT(4) of USERWEIG.

Cheers, Anton

From: Anton Lechner
Sent: 21 February 2014 15:05
To: hayley.smith_at_stfc.ac.uk; fluka-discuss_at_fluka.org
Subject: RE: Computing the distribution of an isotope over the entire geometry

Dear Hayley,

Depending on your specific geometry/materials, it might not always be unambiguous to infer from gamma rays to the number of residual nuclei since photons might reinteract before crossing into another region (i.e. they can loose energy or disappear). In addition, you will not have information about the spatial distribution of the produced nuclei in a certain region.

You can get the individual positions of isotope production via the USRRNC user routine (to be activated via WHAT(4) of the USERWEIG card), which is called every time a residual nucleus is produced. Among the arguments passed to the routine are the atomic number and mass (IZ,IA), the position (X,Y,Z), but also the region (MREG). You could then simply write the positions to a file:

      IF( IZ.EQ.zz .AND. IA.EQ.aa ) THEN
           write X,Y,Z to a file

where zz and aa are the atomic number and mass of your specific isotope. To convert the results into a plot however requires first some post-processing from your side (histogram-filling).

Cheers, Anton

From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of hayley.smith_at_stfc.ac.uk [hayley.smith_at_stfc.ac.uk]
Sent: 04 February 2014 12:22
To: fluka-discuss_at_fluka.org
Subject: [fluka-discuss]: RE: Computing the distribution of an isotope over the entire geometry

Dear All

I have still been struggling with this problem. From further reading I think my approach is definitely incorrect.
From my understanding it seems in order to score a quantity this quantity must first ‘flow’ within FLUKA. Am I correct?

If my understanding is correct I then need to instead identify the method by which the isotope would be produced. I believe this is an (n, gamma) reaction, and then I would score the flow of specific energy gamma rays across boundaries? Would this be the correct approach?

Having read this post http://www.fluka.org/web_archive/earchive/new-fluka-discuss/0936.html it seems like I am trying to do something similar, but I have so far been unsuccessful in being able to score the specific gamma rays using USRBDX and EMFCUT. I was also not able to find the lecture specified in the link.

Many thanks for any advice anyone is able to give with any of this,

From: Smith, Hayley (STFC,RAL,ISIS)
Sent: 28 January 2014 16:32
To: 'fluka-discuss_at_fluka.org'
Subject: Computing the distribution of an isotope over the entire geometry

Dear All

I have a couple of (hopefully) quick questions…

I have a geometry comprising many regions. I wish to compute the distribution of a certain isotope over the entire geometry, after bombardment with a proton beam.

Initially I had hoped to achieve this with a combination of USRBIN and AUXSCORE cards. However I had no luck, and after further reading, specifically: http://www.fluka.org/web_archive/earchive/new-fluka-discuss/1453.html , I decided that this was not a good approach.

As suggested in the above link I attempted to use a USRBDX, with both one-way and two-way current scoring along with AUXSCORE over all of the different boundaries between my many regions. This was marginally more successful, using the ALL-PART selection I saw some results, but when using AUXSCORE to select a specific Z and A I saw nothing.

This was confusing since I had also tried using a RESNUCLEi for each region, to ensure the isotope I wanted to see had been produced. In some regions I could see the isotope, but not in others.

1) Is anyone able to confirm the correct approach for computing the distribution of a certain isotope over an entire geometry?

2) And then the best way to visualise this? I was hoping for something similar to a USRBIN 2D projection, but I am now not sure if this is going to be possible.

Many thanks for any clarification / suggestions on the best way for me to proceed.


Hayley Smith

Accelerator Physicist
ISIS Facility
Rutherford Appleton Laboratory
Harwell Oxford
OX11 0QX

01235 445524

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Received on Fri Feb 21 2014 - 15:07:55 CET

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