Re: Problem with U_238

From: Alberto Fasso' (Alberto.Fasso@cern.ch)
Date: Tue Mar 04 2003 - 13:46:16 CET


The name to be used is 238-U and not 238U (see manual, Chap. 16).

Also, in your input, all MATERIAL definitions are commented off and shifted one
character to the right, so I cannot be sure how the different fields were
actually aligned in your run. But it looks that the string "238U" would
start on column 72 (and not on 71 as it should) if one would just remove
the * on column 1.

Finally, perhaps it doesn't matter too much in your case, but if you
intend to use monoisotopic uranium 238, you should set WHAT(6) = 238.
in the MATERIAL card. If, instead, your intention was to use uranium of
natural composition, you should define a COMPOUND made of the different
uranium natural isotopes (since a cross section set for natural uranium
is not available in the library)

Best regards,

    Alberto

On Tue, 4 Mar 2003, rogov wrote:

>
> Hello Dear Fluka Users,
> my job working fine with many materials in Target
> (Lead, Tungsten, Tantalum, Carbon).
> As only I am insert Uranium - as target,
> my job finish with error:
>
> skipped
> ..............
> ***** Neutron Xsec: ****
> **** Group limits, average energies, velocities and momenta start at location 596161, end at location 596784 (I*4 addr.) *****
> **** Low energy neutron xsec not found for some media 0 1 ****
>
>
>
> I am use Linux version FLUKA: Version of Fluka2002 for Vax, Vms operating system
> Any help will be appreciated!
>
>
>
> *--------------------- My Job ---------------------
> TITLE
> Neutron-spectra after a target for 25 MeV electrons
> DEFAULTS ICARUS
> * 25 MeV Electron Beam
> BEAM -0.025 0.0 0.0 0.0 0.0 0. ELECTRON
> * Beam Starts at Point (0,0,-1) in Z - Direction
> BEAMPOS 0.0 0.0 -1.0 0.0 0.0 0.0
> *
> GEOBEGIN
> 0 0 Target
> *---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
> * A Large Box for the Black Hole
> RPP 1 -999999. 999999. -999999. 999999. -999999. 999999.
> RPP 2 -888888. 888888. -888888. 888888. -888888. 888888.
> * cylinder
> ZCC 3 0.0 0.0 0.2
> * xy-planes for z-regions
> XYP 4 0.0
> XYP 5 0.5
> *
> END
> *-reg-----or-----or-----or-----or-----or-----or-----or-----or-----or
> * Blach Hole: reg 1
> NU1 0 +1 -2
> * Outer Vacuum: reg 2
> VAK 0OR +2 -3OR +2 -5OR +2 +4
> * Target: reg 3
> Tan 0 +3 +5 -4
> *
> END
> GEOEND
> *---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
> *MATERIAL 73.00 180.948 16.654 26.0 0.4094 0.TANTALUM
> *MATERIAL 92.0 238.0 18.95 26.0 0. 238U
> *---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
> *MATERIAL 0.0 0.0 2.51 26.0 0.0 0. U238+C
> *COMPOUND -0.637 6.0 -0.363 18.0 U238+C
> *---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
> * Assign Materials to Regions: non Assigned are Blackhole
> * Vakuum in Zone 2
> ASSIGNMA 2.0 2.0
> * Target Mat. in Zone 3
> ASSIGNMA 18.0 3.0
> *
> *LOW-MAT 6 6.0 -2.0 293.0 CARBON
> *LOW-MAT 18 92.0 238.0 293.0 238U
> *---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
> *
> * Photo-nuclear Interactions on for Target Mat.
> PHOTONUC 1.0 0.0 0.0 18.0 18.0
> *
> PART-THR -1.0E-3 1.0 2.0 1.0 0.0
> PART-THR -1.0E-3 10.0 39.0 1.0 0.0
> *
> * Discard muons
> DISCARD 10. 11.
> EVENTYPE 1.
> * Scoring
> USRBDX -1. 8.0 71.00 3.0 2.0 1. Tgout_Hn
> USRBDX 0.1 .1960E-01 7. &
> USRBDX -1.0 8.0 71.00 3.0 2.0 1. Tgout_Ln
> USRBDX .1960E-01 .1000E-13 72. &
> USRBDX -1.0 1.0 71.00 3.0 2.0 1. Tgout_p
> USRBDX 0.1 .1E-03 20. &
> USRBDX -1.0 7.0 71.00 3.0 2.0 1. Tgout_g
> USRBDX 0.1 .1E-03 60. &
> *
> *---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
> RANDOMIZ 1.
> START 200 . .1E+09
> STOP
>
>
>

-- 
Alberto FassÚ
CERN-EP/AIP, CH-1211 Geneve 23 (Switzerland)
Phone: (41 22) 767 2398    Fax: (41 22) 767 9480   Alberto.Fasso@cern.ch


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