Re: a question about neutron yield

From: Alberto Fasso' (fasso@SLAC.Stanford.EDU)
Date: Wed Jun 07 2006 - 00:56:46 CEST

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    You have activated photonuclear reactions only for material 4, but your
    target is made of iron (material 11 in your input). There is also a comment
    line which says "Be target", but 11 is defined as iron. In any case,
    material 4 (Helium) is not used anywhere.
    The same mistake is in your command PAIRBREM: you need to realize that not all
    commands are specified by region. Some of them, like PHOTONUC and
    PAIRBREM, are specified by material.
    You should also add a command LAM-BIAS, to decrease the photon nuclear
    interaction length, otherwise you will never get sufficient statistics.

    Alberto

    On Tue, 6 Jun 2006, liujt wrote:

    > if this letter bother you, i'm sorry for that
    > i have simulated some example,and i can get right result
    > recently,i simulate the neutron yield with electron beam effecting with the target
    > and the target material is iron.i can get photon score,but i can't get any neutron score in the result
    > this question have bother me many days,and i have change the material of the target.however i can't get
    > any neutron .
    > could you tell me what can i do
    > thank you for your attention
    >
    >
    > *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
    > TITLE
    > Electron fluence inside and around a Fe target
    > *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
    > BEAM 1.89 ELECTRON
    > BEAMPOS 0.0 0.0 -50.0
    > *
    > GEOBEGIN COMBINAT
    > A simple Fe target inside vacuum
    > RPP 1-5000000.0+5000000.0-5000000.0+5000000.0-5000000.0+5000000.0
    > RPP 2-1000000.0+1000000.0-1000000.0+1000000.0-1000000.0+1000000.0
    > RPP 3 -20.0 +20.0 -20.0 +20.0 -20.0 +20.0
    > RPP 4 -10.0 +10.0 -10.0 +10.0 0.0 +5.0
    > END
    > * black hole
    > BH1 5 +1 -2
    > * vacuum around 1
    > VA2 5 +2 -3
    > * vacuum around 2
    > VA3 5 +3 -4
    > * Fe target
    > FE4 5 +4
    > END
    > GEOEND
    > *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
    > MATERIAL 26.0 55.845 7.874 11.0 IRON
    > *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
    > * Be target
    > ASSIGNMAT 11.0 4.0
    > * External Black Hole
    > ASSIGNMAT 1.0 1.0
    > * Vacuum
    > ASSIGNMAT 2.0 2.0
    > ASSIGNMAT 2.0 3.0
    > *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
    > LOW-BIAS 0.0 74.0 1.0 4.0 4.0 1.0
    > LOW-MAT 11.0 26.0 -2.0 293.0 0.0 0.0 IRON
    > LOW-NEUT 72.0 22.0 0.0196 1.0 0.0 -9.0
    > PAIRBREM 3.0 0.0 0.000001 4.0 4.0 1.0
    > EMFCUT 0.0 0.0 0.0 4.0 4.0 1.0 PHOT-THR
    > EMFCUT 0.0 0.0 0.0 4.0 4.0 1.0 PHO2-THR
    > PHOTONUC 1.0 0.0 0.0 4.0 4.0 1.0
    > * score in each region energy deposition and stars produced by primaries
    > SCORE 208.0 210.0 8.0
    > * Boundary neutron crossing current from the target to the vacuum
    > USRBDX +1.0 8.0 -47.0 4.0 3.0 n-out
    > USRBDX +1.89 +50.0 0.0 0.0 0.0 &
    > * Boundary photon crossing current from the target to the vacuum
    > USRBDX 1.0 7.0 -47.0 3.0 4.0 ph-out
    > USRBDX +1.89 +50.0 0.0 0.0 0.0 &
    > * Boundary electron crossing current from the target to the vacuum
    > USRBDX 1.0 3.0 -47.0 3.0 4.0 e-out
    > USRBDX +1.89 +50.0 0.0 0.0 0.0 &
    > * Boundary charged particle crossing current from the target to the vacuum
    > USRBDX 1.0 202.0 -47.0 3.0 4.0 ch-out
    > USRBDX +1.89 +50.0 0.0 0.0 0.0 &
    > *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
    > RANDOMIZE 1.0
    > *...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
    > START 1000.0
    > STOP
    >
    >

    -- 
    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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