RE: Scoring Particle Yields in Thick Targets.

From: Alberto Fasso' (fasso@SLAC.Stanford.EDU)
Date: Thu Feb 22 2007 - 03:11:34 CET

  • Next message: Lindley Winslow: "Particle Yields from mgdraw.f"

    Of course one needs to avoid double counting. I didn't mention the
    "neutron balance" as a mean to avoid double counting, but just as
    another piece of information, that can be added to what can be obtained
    in other ways. I think that Lindley was originally trying to get the neutron
    information using USRYIELD, which also cannot distinguish between muon-induced
    neutrons and neutron-induced neutrons (and, I add, photon-induced neutrons).
    To get that kind of information about the "parent" particle, it
    is necessary to use the mgdraw and the stuprf user routines, and to inspect
    the content of the GENSTK stack after an interaction.
    That is what Yifang did, under guidance by Stefan Roesler, Alfredo Ferrari
    and myself. There was no need to change the source code, only user routines.

    Alberto

    On Wed, 21 Feb 2007, Tang, Alfred wrote:

    > Hi Alberto,
    > If Lindley is interested to reproduce Wang et al.'s neutron production rate
    > (Y. F. Wang et al., PRD 64, 013012 (2001)), wouldn't she need to worry about
    > double counting?--i.e. to distinguish between muon-induced neutrons versus
    > neutron-induced neutrons and so on? I don't think that neutron balance can
    > answer the question of double counting because both primary and secondary
    > neutrons can be absorbed. Please correct me if I misunderstood something.
    > Otherwise I am interested to know if anyone knows what YiFang did for his
    > paper. Did he need to modify the source code for this specific calculation?
    > Regards,
    > Alfred
    >
    >
    > *****************************************************
    > Alfred Tang
    > Physics Department
    > Kansas State University
    > 13 Cardwell Hall
    > Manhattan, KS 66506
    >
    > (785) 532-1699
    >
    > http://www.phys.ksu.edu/personal/atang
    >
    > ________________________________
    >
    > From: owner-fluka-discuss@fisica.unimi.it on behalf of Alberto Fasso'
    > Sent: Tue 2/20/2007 2:14 PM
    > To: Lindley Winslow
    > Cc: Fluka Discussion
    > Subject: Re: Scoring Particle Yields in Thick Targets.
    >
    >
    >
    > Lindley,
    >
    > perhaps you can find the information you are missing by scoring
    > "neutron balance" (generalized particle n. 222). This quantity is
    > defined as the algebraic sum of "created" neutrons minus
    > "disappeared" neutrons, the sum taking place over all interactions
    > in the volume of interest.
    >
    > Alberto
    >
    >
    > On Fri, 16 Feb 2007, Lindley Winslow wrote:
    >
    > > Paola,
    > >
    > > Thank you. I have used fluence to do independent calculations of
    > > nuclei production and I realize that for most problems what you want
    > > is some measure of path length density which USRBIN and USRTRACK
    > > provide for you since that provides more information on interactions
    > > and energy deposition.
    > >
    > > However my problem is that large scintillating or water detectors
    > > quote neutron yields in N per muon or N per muon g/cm2 so you need
    > > to score neutrons more like the scoring with RESNUC does for nuclei.
    > >
    > > I could get this number from mgdraw.f but then you run into
    > > complications with the treatment of low energy neutrons,
    > > I am afraid that I may be missing something obvious so any help would
    > > be greatly appreciated,
    > > Thank you,
    > > Lindley
    > >
    > >
    > >
    > > On Feb 16, 2007, at 1:00 PM, paola sala wrote:
    > >
    > > > Hi Lindley,
    > > >
    > > > yes, you are missing interactions from low energy neutrons: they
    > > > are not
    > > > considered in the "inelastic interactions" usryield scoring. The
    > > > problem, however, is that this use of USRYIELD in a thick target makes
    > > > no sense ( as you already realized). This option is useful for thin
    > > > target studies, when the interest is on one specific reaction.
    > > > In a full shower, the quantity that better characterizes the particle
    > > > fields is the fluence, that you can score either with USRBIN or with
    > > > USRTRACK ( this last gives also an energy spectrum). Fluence is the
    > > > quantity directly related to the response of a detector exposed to the
    > > > particle field.
    > > > ( parenthesis : be sure to activate also photon induced nuclear
    > > > interactions, they play a non-negligible role in problems involving
    > > > muon
    > > > induced showers)
    > > > Paola
    > > >
    > > > On Thu, 2007-02-15 at 15:53 -0800, Lindley Winslow wrote:
    > > >> Hello all,
    > > >>
    > > >> This is a followup to a previous post about using USRYIELD to score
    > > >> particle yields and possible double counting. My goal is to score
    > > >> both particles made in muon and secondary interactions.
    > > >>
    > > >> The previous post can be found here:
    > > >> http://www.fluka.org/web_archive/earchive/new-fluka-discuss/0793.html
    > > >>
    > > >> I wrote a user defined routine to correct for scoring of particles'
    > > >> scattering, spallation etc. which brought my results with ~10% of the
    > > >> published result at 270GeV. I then tried to reproduce results for
    > > >> 10.3GeV muons and I am getting 1.4 instead of 2.5 n per muon g/cm2
    > > >> and 0.1 instead of 0.3 pion+ per muon g/cm2.
    > > >>
    > > >> I realized by scoring inelastic collisions I was missing particle
    > > >> decays which I thought was a small correction. I think I may also be
    > > >> missing particles created in Low Energy Neutron interactions. If so
    > > >> what is the proper way to score these particles? or may be more
    > > >> generally what is the proper way to score particle yields in thick
    > > >> detectors? (Detectors where total amount produced is more important
    > > >> than what escapes).
    > > >>
    > > >> Thank you,
    > > >> Lindley
    > > >>
    > > >>
    > >
    > >
    >
    > --
    > Alberto FassÚ
    > SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025
    > Phone: (1 650) 926 4762 Fax: (1 650) 926 3569
    > fasso@slac.stanford.edu
    >
    >
    >
    >
    >

    -- 
    Alberto FassÚ
    SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025
    Phone: (1 650) 926 4762   Fax: (1 650) 926 3569
    fasso@slac.stanford.edu
    

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