RE: Scoring number of elastic collissions

From: Vasilis Vlachoudis (Vasilis.Vlachoudis@cern.ch)
Date: Mon Mar 05 2007 - 10:50:10 CET

  • Next message: Sunil C: "Re: Scoring number of elastic collissions"

    Hi Sunil,

    the mdstck is used to manage the stack of particles produced after an
    interaction. In elastic collisions there are no secondaries produced
    unless you have a recoil on the target nucleus e.g. if it is a hydrogen
    atom.

    Cheers
    Vasilis

    -----Original Message-----
    From: Sunil C [mailto:sunilc@barc.gov.in]
    Sent: Monday, 05 March 2007 09:37
    To: Vasilis Vlachoudis
    Subject: Re: Scoring number of elastic collissions

    Hi

    I am sorry to bother you again. I posted the query to the list but none
    replied. So I still would like to know if have a way to score the
    elastic collisions from the low energy neutron group.
    Going back to the manual CERN-2005 -10 page number 310 the MDSTACK can
    be used to analyze or write the secondaries to a file. Do you think this

    would work? or is there any other variable that can be tapped. I am
    trying to compare the number with a MCNP calculation.

    Best Regards
    Sunil

    Vasilis Vlachoudis wrote:
    > Dear Sunil,
    >
    > you have to be careful with the low energy neutrons (En<19.6 MeV), the
    > routine that I've send doesn't apply to them. It only works down to
    19.6
    > MeV, and not below when the neutrons are treated with the group
    > approach. Is true that you can activate point-wise treatment for some
    > elements [LOW-NEUT, what(6) card] like Hydrogen, but then the event
    flag
    > for scoring the elastic scattering is no longer the LELEVT, but rather
    > the LLENSC for both elastic and inelastic. Otherwise, the stuprf for
    > these neutrons will be called only when there is an event that
    generates
    > a secondary particle in the stack i.e. proton recoil.
    >
    > Best Regards
    > Vasilis
    >
    > -----Original Message-----
    > From: Sunil C [mailto:sunilc@barc.gov.in]
    > Sent: Friday, 02 March 2007 08:03
    > To: Vasilis Vlachoudis
    > Subject: Re: Scoring number of elastic collissions
    >
    > Hi
    >
    > Thanks a lot
    > If let us say the medium is hydrogen in which i need to count, the
    > energy of neutron is within the low energy group say 1 MeV then is it
    > possible to do so by switching off the inelastic collision, switch on
    > all elastic collisions by threshold card and not transporting the
    > protons so that it does not escape the region. These can be counted
    with
    >
    > USRBIn card. The number of protons will be more or less equal to the
    > fluence in the region. I may be wrong also because if not transported
    > the whole energy is deposited in the region. But these will not give
    the
    >
    > number of collissions.
    >
    > Just a train of thought
    >
    > Best Regards
    > Sunil
    >
    > Vasilis Vlachoudis wrote:
    >
    >> Hi Sunil,
    >>
    >>
    >>
    >> I would do something like the following:
    >>
    >> I will use the stuprf.f routine to increase the particle variable
    >> ISPARK (1,NPFLKA) for every elastic event, like:
    >>
    >> IF ( LELEVT ) THEN
    >>
    >> * Increment number of elastic scatterings
    >>
    >> ISPARK (1,NPFLKA) = ISPARK (1,NPFLKA) + 1
    >>
    >> END IF
    >>
    >> And then use the USERDUMP with a modified MGDRAW routine to dump the
    >> ISPARK variable which at this level should become ISPUSR(1), based on

    >> the coditions: 1:falls below threshold, or 2. exists the system
    >>
    >> * Write Neutrons
    >>
    >> IF (JTRACK.EQ.8) THEN
    >>
    >> IF (ICODE.EQ.31 .OR. ICODE.EQ.12) THEN
    >>
    >> * Stopping or below threshold (POSITIVE) Unit:50
    >>
    >> WRITE (90, *) ISPUSR(1)
    >>
    >> ELSE IF(ICODE.EQ.14 .OR. ICODE.EQ.23 .OR. ICODE.EQ.32) THEN
    >>
    >> * Escapping from the geometry (NEGATIVE)
    >>
    >> WRITE (90, *) -ISPUSR(1)
    >>
    >> END IF
    >>
    >> END IF
    >>
    >>
    >>
    >> Of course you have to activate the call to userdump and set the
    proper
    >>
    >
    >
    >> cuts with the low-bias to stop the group treatment of the low-energy
    >> neutrons
    >>
    >> like:
    >>
    >> LOW-BIAS 1.0 73.0 1 100
    >>
    >> USERDUMP 100.0 40.0 5.0

    >> userdump
    >>
    >> OPEN 90.0

    >> UNKNOWN
    >>
    >> neutcount
    >>
    >>
    >>
    >>
    >>
    >> In the routine I am using the sign on the number of scatterings to
    >> discriminate if they fall below the threshold or they escape the
    >>
    > system.
    >
    >>
    >>
    >> Cheers
    >>
    >> Vasilis
    >>
    >>
    >>
    >
    ------------------------------------------------------------------------
    >
    >> *From:* owner-fluka-discuss@fisica.unimi.it
    >> [mailto:owner-fluka-discuss@fisica.unimi.it] *On Behalf Of *Sunil C
    >> *Sent:* Thursday, 01 March 2007 14:00
    >> *To:* fluka-discuss@fluka.org
    >> *Subject:* Scoring number of elastic collissions
    >>
    >>
    >>
    >> Hi All
    >>
    >> I would like to count the number of elastic collissions a fast
    neutron
    >>
    >
    >
    >> undergoes before reaching the thermal energy. I see that this
    >> information is scored in the MDSTACK. How do i extract these
    >>
    > information?
    >
    >>
    >>
    >> Best Regards
    >>
    >> Sunil
    >>
    >>
    >
    >
    >
    >


  • Next message: Sunil C: "Re: Scoring number of elastic collissions"

    This archive was generated by hypermail 2.1.6 : Mon Mar 05 2007 - 11:07:30 CET