RE: Question about neutron balance

From: Vasilis Vlachoudis (Vasilis.Vlachoudis@cern.ch)
Date: Tue Mar 06 2007 - 10:09:45 CET

  • Next message: Lindley Winslow: "Neutron Yields Below 19.6MeV"

    Hi Alfred,

    the numbers mean nothing to me!
    USRTRACK and USRCOLL both score particle fluence using two different
    methods one with the track length estimation and the other by
    collisions. Please give a look to the related tutorial on the fluka web
    site http://www.fluka.org/course/WebCourse/scoring/P007.html
    Check also the USRYIELD card for scoring particle yields out of an
    interaction or a region

    Regards
    Vasilis

    -----Original Message-----
    From: Tang, Alfred [mailto:atang@phys.ksu.edu]
    Sent: Monday, 05 March 2007 17:16
    To: Vasilis Vlachoudis; fluka-discuss@fluka.org
    Subject: RE: Question about neutron balance

    Dear Vasilis,
    Thank you for your comments. They are very informative. I have used
    source.f to input muons from a realistic profile and to score the
    secondary particles using USRTRACK and USRCOLL. Below is a partial list
    of the numbers that I got in unit of p/cmq/pr and cm/pr (I used the
    default area=1cm^2 and volume=1cm^3):

    USRTRACK
    muon 1184.364
    particle 8 20.14018
    particle 222 6418.346

    USRCOLL
    muon 1161.683
    particle 8 20.13256
    particle 222 1180.406

    Do these numbers look right? What is the main difference between
    USRTRACK and USRCOLL? I am primarily interested in the production rates
    of secondary particles. Can I get that information from the above
    numbers? Thanks again.
    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

    -----Original Message-----
    From: owner-fluka-discuss@fisica.unimi.it on behalf of Vasilis
    Vlachoudis
    Sent: Sun 3/4/2007 11:56 AM
    To: Tang, Alfred; fluka-discuss@fluka.org
    Subject: RE: Question about neutron balance
     
    Hi Alfred,

    The neutron balance according to your definition is related to B. Is the
    term that enters in the diffusion equation for a steady in time
    solution.
    The diffusion equation is described as:
    d(Flux(r))/dt = D*\Delta2(Flux(r)) + S(r) - \Sigma_abs*Flux(r)
    where S(r) term describing the sources and \Sigma_abs the absorption
    cross section:
    or with words the diffusion equation is (per unit volume):

    dFlux(r)/dt = -[outflow rate] + [production rate] - [absorption rate]

    and for a steady state solution

    [outflow rate] = [production rate] - [absorption rate] = neutron balance

    While the particle 8=neutron is scoring the neutron fluence. The datum
    most frequently used for describing neutron fields. The fluence defined
    as the number of particles that penetrate a sphere with a cross section
    of pi*r^2 = 1cm2 per unit of time and/or energy. Otherwise, the
    particles crossing a surface of 1cm2 that is ALWAYS perpendicular to the
    direction of the particle.

    Regards
    Vasilis

    -----Original Message-----
    From: owner-fluka-discuss@fisica.unimi.it
    [mailto:owner-fluka-discuss@fisica.unimi.it] On Behalf Of Tang, Alfred
    Sent: Friday, March 02, 2007 17:08
    To: fluka-discuss@fluka.org
    Subject: Question about neutron balance

    This is a multi-part message in MIME format.

    ------_=_NextPart_001_01C75CE4.F09333FC
    Content-Type: text/plain;
            charset="US-ASCII"
    Content-Transfer-Encoding: quoted-printable

    Dear FLUKA experts,
    Suppose that A=3D(number of neutrons created)+(number of neutrons
    absorbed) and B=3D(number of neutrons created)-(number of neutrons
    absorbed). Is it true that neutron balance (particle number 222)
    neut-bala is related to A and neutron (particle number 8) is related to
    B?
    Regards,
    Alfred
    =20

    **********************************************
    Alfred Tang
    Department of Physics
    Kansas State University
    13 Cardwell Hall
    Manhattan, KS 66506

    (785) 532-1699

    http://www.phys.ksu.edu/personal/atang

    ------_=_NextPart_001_01C75CE4.F09333FC
    Content-Type: text/html;
            charset="US-ASCII"
    Content-Transfer-Encoding: quoted-printable

    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
    <HTML>
    <HEAD>
    <META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; =
    charset=3Dus-ascii">
    <META NAME=3D"Generator" CONTENT=3D"MS Exchange Server version =
    6.5.7651.59">
    <TITLE>Question about neutron balance</TITLE>
    </HEAD>
    <BODY>
    <!-- Converted from text/rtf format -->

    <P><FONT SIZE=3D2 FACE=3D"Arial">Dear FLUKA experts,</FONT>

    <BR><FONT SIZE=3D2 FACE=3D"Arial">Suppose that A=3D(number of neutrons =
    created)+(number of neutrons absorbed) and B=3D(number of neutrons =
    created)-(number of neutrons absorbed).&nbsp; Is it true that neutron =
    balance (particle number 222) neut-bala is related to A and neutron =
    (particle number 8) is related to B?</FONT></P>

    <P><FONT SIZE=3D2 FACE=3D"Arial">Regards,</FONT>

    <BR><FONT SIZE=3D2 FACE=3D"Arial">Alfred</FONT>

    <BR><FONT SIZE=3D2 FACE=3D"Arial">&nbsp;</FONT>
    </P>

    <P><FONT SIZE=3D2 =
    FACE=3D"Arial">**********************************************</FONT>

    <BR><FONT SIZE=3D2 FACE=3D"Arial">Alfred Tang</FONT>

    <BR><FONT SIZE=3D2 FACE=3D"Arial">Department of Physics</FONT>

    <BR><FONT SIZE=3D2 FACE=3D"Arial">Kansas State University</FONT>

    <BR><FONT SIZE=3D2 FACE=3D"Arial">13 Cardwell Hall</FONT>

    <BR><FONT SIZE=3D2 FACE=3D"Arial">Manhattan, KS 66506</FONT>
    </P>

    <P><FONT SIZE=3D2 FACE=3D"Arial">(785) 532-1699</FONT>
    </P>

    <P><A HREF=3D"http://www.phys.ksu.edu/personal/atang"><U><FONT =
    COLOR=3D"#0000FF" SIZE=3D2 =
    FACE=3D"Arial">http://www.phys.ksu.edu/personal/atang></U></A>
    </P>

    </BODY>
    </HTML>
    ------_=_NextPart_001_01C75CE4.F09333FC--


  • Next message: Lindley Winslow: "Neutron Yields Below 19.6MeV"

    This archive was generated by hypermail 2.1.6 : Tue Mar 06 2007 - 10:20:34 CET