Re: [fluka-discuss]: Dose in Vacuum using USRBIN DOSE-EQ?

From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>
Date: Thu, 28 Jul 2016 21:57:00 +0200

Dear Cillian,

dose and dose equivalent are two well distinct quantities (as clearly reminded
in the manual): the first is deposited energy per unit mass, the second is
particle fluence weighted by various sets of conversion coefficients. So it's
pretty normal that dose eq. is not null in vacuum (contrary to dose: energy is
not deposited in vacuum, but one can find particles there) and does not rigidly
reflect dose.

Best regards

Francesco

**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. ++41 22 7678962
fax ++41 22 7668854

On Tue, 26 Jul 2016, Cillian Murphy wrote:

> Dear Fluka experts,
> My name is Cillian Murphy,
> I'm doing radiation shielding simulations at EAC, Cologne for my Masters
> research.
>
> I've noticed something odd about some of my results using USRBIN. I'm
> plotting DOSE, ENERGY, and DOSE-EQ for a large rectangular space around my
> target region. I'm simulating protons, neutrons and heavy ions from GCR,
> Solar wind and SPEs. The strange thing that I've noticed is that DOSE-EQ
> gives a distinctly non-zero value for deposition in the vacuum surrounding
> the target region, surely as with DOSE this result should be 0 everywhere in
> vacuum?
>
> One other thing that I've noticed and am curious about though I don't think
> it's wrong is that DOSE and DOSE-EQ do not produce directly comparable
> results (aside from the odd deposition in vacuum), the results are of very
> similar order and are very similar to look at, however they do not match as
> well as I had initially expected though I now suspect that this is due to
> differing radiation weighting factors for the secondaries. I feel it's
> better to be safe than sorry so I thought I'd confirm this while I'm writing
> anyway.
>
> I hope that you can explain these details for me or point out where I'm
> going wrong.
> I'll attach one of the odd outputs as well as including my most recent .inp.
> I'm using Flair in case that could somehow be responsible. This is also a
> WIP I've only just started producing meaningful results after struggling for
> some time to get FLUKA working properly, I'll be refining most aspects of
> the simulation over several iterations.
>
> Thank you for your time,
> Cillian
>
>
> investigate.inp:
>
> TITLE Habitat Shield Simulation 
>
> * Set the defaults for precision simulations
> DEFAULTS                                                            
>  PRECISIO
> GEOBEGIN                                                            
>  COMBNAME
>     0    0          
> SPH BLKHLBND   0.0 0.0 0.0 100000.
> SPH SIMLNSPH   0.0 0.0 0.0 10000.
> RCC HABWLOUT   0.0 -250.0 0.0 0.0 500. 0.0 550.
> RCC HABWLLIN   0.0 -250.0 0.0 0.0 500.0 0.0 500.
> XYP PLNDIVDR   0.0
> SPH TSTSPHR1   160. 0.0 300.0 50.
> SPH TSTSPHR2   300.0 0.0 -250. 50.
> SPH TSTSPHR3   -400.0 0.0 200. 50.
> SPH TSTSPHR4   -180.0 0.0 -400.0 50.
> XZP TSTBNDY1   250.0
> XZP TSTBNDY2   -250.0
> SPH TSTSPHR5   0.0 0.0 0.0 50.
> XYP SURFLINE   0.0
> SPH LUNARBND   0.0 0.0 0.0 5000.0
> END
> BOUNDARY     5 -BLKHLBND
> VACUUMAR     5 +BLKHLBND -(+HABWLOUT +TSTBNDY1 -TSTBNDY2) -(-HABWLOUT
> -SURFLINE +TSTBNDY1 -TSTBNDY2 +LUNARBND )
> HABSHILD     5 +HABWLOUT -HABWLLIN
> HABATMSP     5 +HABWLLIN -TSTSPHR1 -TSTSPHR2 -TSTSPHR3 -TSTSPHR4 -TSTSPHR5
> TSTSPHR1     5 +TSTSPHR1
> TSTSPHR2     5 +TSTSPHR2
> TSTSPHR3     5 +TSTSPHR3
> TSTSPHR4     5 +TSTSPHR4
> TSTSPHR5     5 +TSTSPHR5
> LUNRSURF     5 -HABWLOUT -SURFLINE +TSTBNDY1 -TSTBNDY2 +LUNARBND
> END
> GEOEND
> *BEAM            -0.1       0.0       0.0       0.0       0.0        
>  PROTON
> BEAM           -0.02       0.0       0.0    1500.0     600.0       1.0PROTON
> BEAMPOS          0.0       0.0   -1000.0
> * SiO2 (quartz)
> * The density of SiO2 may vary from 2.3 - 2.5 g/cm3 depending on the
> * method of preparation. Under ion bombardment, the surface density
> * will change towards an equilibrium value of about 2.37.
> MATERIAL                            2.32                              SiO2
> COMPOUND         2.0    OXYGEN       1.0   SILICON                    SiO2
> * Titanium dioxide Ti_O2
> *
> MATERIAL                            4.26                              TiO2
> COMPOUND   -0.400592    OXYGEN -0.599408  TITANIUM                    TiO2
> * Aluminum Oxide (alpha)
> * The density of aluminum oxide will vary by 5% according to the
> * method of preparation.
> MATERIAL                            3.98                              Al2O3
> COMPOUND         2.0  ALUMINUM       3.0    OXYGEN                    Al2O3
> * Ferric oxide Fe2_O3
> *
> MATERIAL                             5.2                              Fe2O3
> COMPOUND   -0.300567    OXYGEN -0.699433      IRON                    Fe2O3
> * Ferrous oxide Fe_O
> *
> MATERIAL                             5.7                              FeO
> COMPOUND   -0.222689    OXYGEN -0.777311      IRON                    FeO
> MATERIAL         25.                7.21                            
>  MANGANES
> * Manganese Oxide (MnO)
> * Material added by Cillian Murphy 08/06/16 to define lunar regolith
> simulant materials for radiation shielding simulations.
> MATERIAL                            5.43                            
>  MANGOXID
> COMPOUND         1.0  MANGANES       1.0    OXYGEN                  
>  MANGOXID
> * MgO (Magnesia)
> * Material added by Cillian Murphy 08/06/16 to define lunar regolith
> simulant materials for radiation shielding simulations.
> MATERIAL                            3.58                            
>  MAGNESIA
> COMPOUND         1.0  MAGNESIU       1.0    OXYGEN                  
>  MAGNESIA
> * Calcium oxide Ca_O
> *
> MATERIAL                             3.3                              CaO
> COMPOUND   -0.285299    OXYGEN -0.714701   CALCIUM                    CaO
> * Sodium monoxide Na2_O
> *
> MATERIAL                            2.27                              Na2O
> COMPOUND   -0.258143    OXYGEN -0.741857    SODIUM                    Na2O
> MATERIAL         19.               0.862                            
>  POTASSIU
> * Potassium oxide K2_O
> *
> MATERIAL                            2.32                              K2O
> COMPOUND   -0.169852    OXYGEN -0.830148  POTASSIU                    K2O
> MATERIAL         15.                1.82                            
>  PHOSPHO
> * P2O5 (Phosphorus Pentoxide)
> *
> MATERIAL                            2.39                            
>  PHOSPNTO
> COMPOUND         2.0   PHOSPHO       5.0    OXYGEN                  
>  PHOSPNTO
> MATERIAL                            1.98                              JSC1A
> COMPOUND      -42.95      SiO2     -1.57      TiO2    -14.53     Al2O3JSC1A
> COMPOUND       -11.5     Fe2O3     -7.52       FeO     -0.17  MANGOXIDJSC1A
> COMPOUND       -8.64  MAGNESIA     -9.11       CaO      -2.6      Na2OJSC1A
> COMPOUND       -0.71       K2O     -0.65  PHOSPNTO                    JSC1A
> ASSIGNMA    BLCKHOLE  BOUNDARY
> ASSIGNMA      VACUUM  VACUUMAR
> ASSIGNMA       JSC1A  HABSHILD
> ASSIGNMA         AIR  HABATMSP
> ASSIGNMA       WATER  TSTSPHR1
> ASSIGNMA       WATER  TSTSPHR2
> ASSIGNMA       WATER  TSTSPHR3
> ASSIGNMA       WATER  TSTSPHR4
> ASSIGNMA       WATER  TSTSPHR5
> ASSIGNMA       JSC1A  LUNRSURF
> USRBIN           10.      DOSE      -21.    1000.0     300.0  
>  1000.0BXBLKDOS
> USRBIN       -1000.0    -300.0   -1000.0      255.      255.      255. &
> USRBIN           10.    ENERGY      -22.    1000.0     300.0  
>  1000.0BXBLKENG
> USRBIN       -1000.0    -300.0   -1000.0      255.      255.      255. &
> USRBIN           10.   DOSE-EQ      -23.    1000.0     300.0  
>  1000.0BXBLKDEQ
> USRBIN       -1000.0    -300.0   -1000.0      255.      255.      255. &
> * Set the random number seed
> RANDOMIZ         1.0
> * Set the number of primary histories to be simulated in the run
> START       1000000.
> STOP
>
>

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Received on Thu Jul 28 2016 - 23:38:25 CEST

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