Fission in uranium

From: Lutz Moritz (lutz.moritz@triumf.ca)
Date: Wed Apr 14 2004 - 18:35:34 CEST

  • Next message: Alfredo Ferrari: "Re: Fission in uranium"

    I am trying to investigate the production of radionuclides in targets of
    uranium carbide bombarded by 500 MeV protons. There are two types of
    targets: those that are bombarded directly by the proton beam and those
    where the proton beam hits a central core of tantalum surrounded by a
    blanket of uranium carbide. I get a 'reasonable'-looking distribution of
    radionuclides for both types of targets using RESNUC (direct.eps and
    twostage.eps), but would like to know the contribution made in each case
    by high-energy fission and low-energy fission (one would expect there to
    be a greater relative contribution from low-energy fission in the
    two-stage target, but in fact there appear to be fewer). But when I try
    to score the different types of fission using generalized particle types
    219, 220 and 221 in USRBIN, I get only zeroes. I don't think I have made
    a mistake in the USRBIN command as I also tried scoring the protons and
    get a non-zero distribution. What am I doing wrong? The input file for
    the direct target (isacdirect.inp) is attached.

    -- 
    Lutz Moritz
    TRIUMF
    4004 Wesbrook Mall
    Vancouver, B.C. V6T 2A3
    Canada
    ------------------------------------------------------------------------
    Tel: 604 222 7372
    E-mail:  lutz.moritz@triumf.ca <mailto:lutz.moritz@triumf.ca>
    Website:  http://www.triumf.ca/EHS
    
    
    
    

    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    * This is the setup for an ISAC UC2 target
    * Lutz Moritz, June 2004
    TITLE
    ISAC UC2 direct target
    * *
    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    ******************* GEOMETRY DEFINITION *********************************
    GEOBEGIN COMBINAT
        0 0 ISAC UC2 Target
    *
    * X-axis up, Y-axis right, Z-axis into the page.
    * Origin is at the centre of the target
    *
    * Body Definitions
    *
    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    *
    * External void
    *
      RPP 1 -999999.9 999999.9 -999999.9 999999.9 -999999.9 999999.9
    *
    * Target cylinder
    *
      ZCC 2 0.0 0.0 0.9
    *
    * Surrounding vacuum
    *
      RCC 3 0.0 0.0 -5.0 0.0 0.0 23.0
                    15.0
    *
    * Scoring planes along target
    *
      XYP 4 0.0
      XYP 5 18.0
    *
    * Plane for cut-out for ion streaming
    *
      YZP 6 0.5
    *
      END
    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    *
    * Region Definitions
    *
    **REG.....OR....1OR....2OR....3OR....4OR....5OR....6OR....7OR....8OR....9
    *
    * 1) Black hole around geometry
    *
      BH1 +1 -3
    *
    * 2) Target
    *
      TA2 +2 +6 +5 -4
    *
    * 3) Surrounding vacuum
    *
      VC3 +3 +4
      VC4 +3 -2 +5 -4
      VC5 +3 -5
      VC6 +2 -6 +5 -4
    *
      END
    **REG.....OR....1OR....2OR....3OR....4OR....5OR....6OR....7OR....8OR....9
    *
    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    *
    GEOEND
    *
    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    *GEOEND 400.0 400.0 1000.0 -400.0 -400.0 -500.0DEBUG
    *GEOEND 80.0 80.0 200.0 &
    *STOP
    *
    ******************* MATERIAL DEFINITIONS ********************************
    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    *
    MATERIAL 6.0 12.011 2.0 3.0 0.0 0.0CARBON
    MATERIAL 92.0 238.000 19.07 4.0 0.0 0.0URANIUM
    *
    * Note: density of UC2 assumed to be 45% of actual because target is made of
    * stack of thin disks
    *
    MATERIAL 0.0 0.0 5.076 5.0 0.0 0.0UC2
    COMPOUND 1.0 4.0 2.0 3.0 0.0 0.0UC2
    *
    LOW-MAT 3.0 6.0 -2.0 293.0
    LOW-MAT 4.0 92.0 238.0 293.0
    *
    ************* Material to region correspondence *************************
    *
    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    ASSIGNMA 1.0 1.0 BLACKHOLE
    ASSIGNMA 5.0 2.0 UC2
    ASSIGNMA 2.0 3.0 6.0 VACUUM
    **
    *PLOTGEOM 1.0 1.0 0.0 -5000.0 1.0 0.0NOFORMAT
    *UC2 Target X-Z Plane
    * 0.0 0.0 -1.0 5.0 0.0 19.0
    * 1.0 0.0 0.0 0.0 0.0 1.0
    * 1.0 1.0
    *PLOTGEOM 1.0 1.0 0.0 -5000.0 1.0 0.0NOFORMAT
    *UC2 Target X-Y Plane
    * -10.0 -10.0 2.5 10.0 10.0 2.5
    * 1.0 0.0 0.0 0.0 1.0 0.0
    * 1.0 1.0
    *STOP
    *
    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    ******************* BEAM SPECIFICATION **********************************
    *
    BEAM -0.500 0.0 0.0 -0.25 -0.25 0.0PROTON
    *
    BEAMPOS 0.0 0.0 -0.1 0.0 0.0 0.0
    *
    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    ******************* EVENT GENERATOR, PARTICLES AND FIELDS ***************
    *
    PHYSICS 2.0 0.0 0.0 0.0 0.0 0.0EVAPORAT
    *
    * Activate to discard neutrinos and antineutrinos,
    DISCARD 5.0 6.0
    *
    * Activate to discard pi-zeros, electrons and photons
    DISCARD 23.0 3.0 4.0 7.0
    *
    * Activate to discard muons
    DISCARD 10.0 11.0
    *
    * Set threshold to 19.6 MeV for neutrons
    *
    PART-THR -0.0196 8.0
    *
    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    ******************* LOW ENERGY NEUTRONS *********************************
    *
    * Switch on low-energy neutron transport
    *
    LOW-NEUT 72.0 22.0 0.0196 0.0
    *
    *
    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    ******************* OUTPUT AND SCORING **********************************
    *
    * Set star threshold to 50 MeV
    *
    THRESHOLD 0.0 0.0 0.0 0.0 0.0 0.05
    *
    EMF EMF-OFF
    *
    RESNUCLE 3.0 72.0 0.0 0.0 2.0 36.4855
    *
    SCORE 208.0 201.0
    *
    * Score beam particles
    *
    USRBIN 11.0 210.0 73.0 5.0 0.0 19.0
    USRBIN 0.0 0.0 -1.0 20.0 1.0 40.0&
    *
    * Score high-energy fission
    *
    USRBIN 11.0 220.0 74.0 5.0 0.0 19.0
    USRBIN 0.0 0.0 -1.0 20.0 1.0 40.0&
    *
    * Score low-energy fission
    *
    USRBIN 11.0 221.0 75.0 5.0 0.0 19.0
    USRBIN 0.0 0.0 -1.0 20.0 1.0 40.0&
    *
    * Score fissions
    *
    USRBIN 11.0 219.0 76.0 5.0 0.0 19.0
    USRBIN 0.0 0.0 -1.0 20.0 1.0 40.0&
    *
    *************** START SIMULATION ************************************
    * Read seeds from unit 1
    RANDOMIZE 1.0
    * Start the calculation
    * /No. protons/No. stars/Print time/Inc.beam//default interactive tlim./
    *...+....1....+....2....+....3....+....4....+....5....+....6....+....7...
    *STOP
    START 5.0E+05 1.0E+09 80.0
    STOP




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