Re: The FLUKA result is just 10 times lower than analytic one?

From: Stefan Roesler (sroesler@mail.cern.ch)
Date: Fri Jun 08 2007 - 09:04:21 CEST

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    Hello Yuanjie Bi,

    I can confirm your FLUKA-result of 2.0406E+11Bq/cm^3. The 7Be production
    cross section predicted with the most recent FLUKA version is actually
    15mb.

    However, I cannot reproduce your analytical result: the saturation yield
    is 1.002E-7 7Be/primary, the beam intensity is 1.248E15 p/second and the
    built-up factor is (for tirr=42.72days) 0.4263. The product of the three
    factors divided by the volume of your region (foil) gives 2.0011E11
    Bq/cm^3.

    Regards
    Stefan

    On Mon, 4 Jun 2007, Yuanjie BI wrote:

    > Hi Fluka users,
    >
    > I am reserching the radioactivity of a thin carbon foil bombed by 100MeV proton.
    > The production of Be7 calculated by FLUKA is 2.03E+11Bq/cmc, but my analytic
    > result using the cross section of 13mb is 1.95E+12Bq/cmc.
    >
    > I have checked the input many times and can't find the reason,is my input file
    > correct ?
    >
    > By the way, how could I know the cross section used by FLUKA?
    >
    >
    > Many thanks for your help
    > Best regards
    >
    > Yuanjie Bi
    > -------------------------------------------------------------------------------
    > TITLE
    > C foil bombarded by 100MeV protons
    > GLOBAL 1.0 1.0
    > DEFAULTS NEW-DEFA
    > BEAM -0.1 0.5 0.8 PROTON
    > BEAMPOS 0.0 0.0 -0.0001
    > PHYSICS 3.0 EVAPORAT
    > PHYSICS 1.0 COALESCE
    > GEOBEGIN COMBNAME
    > 0 0 C foil inside vacuum
    > * Black body
    > RPP blkbody -500.0 500.0 -500.0 500.0 -500.0 500.0
    > * void
    > RPP void -100.0 100.0 -100.0 100.0 -10.0 100.0
    > * target
    > RPP target -1.0 1.0 -1.0 1.0 0.0 6.66D-05
    > END
    > * Black hole
    > BLKBODY 5 +blkbody -void
    > * Void around
    > VOID 5 +void -target
    > * Target
    > TARGET 5 +target
    > END
    > GEOEND
    > * ..+....1....+....2....+....3....+....4....+....5....+....6....+....7..
    > ASSIGNMA BLCKHOLE BLKBODY
    > ASSIGNMA VACUUM VOID
    > ASSIGNMA CARBON TARGET
    > LOW-NEUT 1.0
    > EMF EMF-OFF
    > DISCARD ELECTRON POSITRON PHOTON MUON+ MUON- PIZERO
    > LAM-BIAS 0.0002 CARBON PROTON NEUTRON 7.0INEALL
    > LOW-BIAS 73.0 72.0 0.85 VOID TARGET 1.0
    > RADDECAY 1.0 3.0 0.0 99999
    > IRRPROFI 3691008.0 1.248D+15
    > DCYTIMES 0.0 28800.0 86400.0 604800.0 2592000.0 10368000.
    > DCYSCORE 1.0 A A RESNUCLE
    > RESNUCLE 1.0 -21.0 TARGET 0.000266A
    > DCYSCORE 2.0 B B RESNUCLE
    > RESNUCLE 1.0 -22.0 TARGET 0.000266B
    > RANDOMIZ 1.0
    > START 1.D8 0.0
    > STOP
    >
    >
    > 

    -- 
___________________________________
Stefan Roesler
CERN, SC/RP
CH-1211 Geneva 23
Switzerland
Phone:  +41-22-7679891
Fax:    +41-22-7669639
E-mail: Stefan.Roesler@cern.ch
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