Re: [fluka-discuss]: simulate 100kV X-ray generation

From: Vittorio Boccone <dr.vittorio.boccone_at_ieee.org>
Date: Sat, 3 May 2014 13:03:45 +0200

Dear Fred,
 the energy you have in the file is 40 keV not 100 keV.

From the setting point of view I would avoid the use the of the DEFAULT
EM-CASCA and rather go for PRECISO (in this case you also need to specify
the card EMFFLUO explicitly) and lower down the values acceptable for your
problem.

MULSOPT WHAT[4]-[6] control the single scattering option at the border. In
your particular case
I would rather have a safer.

*...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+...
MULSOPT 0.0 0.0 0.0 1.0 1.0 99999999.GLOBAL

In addition the resulting angular distribution might be smeared out by the
beam dimension

Vittorio


On Fri, May 2, 2014 at 6:23 PM, Fred Sun <y33sun_at_uwaterloo.ca> wrote:

> Dear FLUKA experts,
>
> I am trying to simulate a low energy electron beam (100 KeV) hitting a
> tungsten target to generate X-ray using single scattering mode. I need to
> get angular distribution and yield of photons.
>
> The problem is the angular distribution is incorrect. The correct angular
> distribution is butterfly shape in a polar coordinate system. But the
> result I got is a even distribution in a Cartesian coordinate system in
> USRYIELD.
>
> I put the input file below. Can anyone kindly give some suggestions? Did
> I missing some card? Or should I use the step size and mean free path?
>
> Thanks,
>
> Fred
> ----------------------------------------------------------------------
>
> TITLE
> 100KV
> * Set the defaults for precision simulations
> DEFAULTS
> EM-CASCA
> * Define the beam characteristics
> BEAM -4.E-5 0.01 0.01
> ELECTRON
> * Define the beam position
> BEAMPOS 0.0 0.0 -2.0 0.0 0.0
> MULSOPT 1. 1.
> GLOBEMF
> EMFCUT -1.E-6 1E-7 VACUUM TUNGSTEN
> PROD-CUT
> !arrow 0.0 0.0 -2.0 2. 500.
> 1.beam-a
> !arrow 0.0 0.0 2.0 &
> GEOBEGIN
> COMBNAME
> 0 0
> * Black body
> SPH blkbody 0.0 0.0 0.0 5.0
> * Void sphere
> SPH vac1 0.0 0.0 0.0 4.5
> * Void sphere
> SPH vac2 0.0 0.0 0.0 4.0
> * Cylindrical target
> RCC target 0.0 0.0 0.0 0.0 0.0 0.001 2.0
> END
> * Black hole
> BLKBODY 5 +blkbody -vac1
> * Void around
> VAC1 5 +vac1 -vac2
> * Void around
> VAC2 5 +vac2 -target
> * Target
> TARGET 5 +target
> END
> GEOEND
> * ..+....1....+....2....+....3....+....4....+....5....+....6....+....7..
> ASSIGNMA BLCKHOLE BLKBODY
> ASSIGNMA VACUUM VAC1
> ASSIGNMA VACUUM VAC2
> ASSIGNMA TUNGSTEN TARGET
> USRBIN 10. ELECTRON -21. 0.1 0.1 0.1e-bin
> USRBIN -0.1 -0.1 -0.1 100. 100. 100. &
> USRBIN 10. PHOTON -21. 0.1 0.1 0.1p-bin
> USRBIN -0.1 -0.1 -0.1 100. 100. 100. &
> USRYIELD 176. ELECTRON -31. VAC2 VAC1
> 1.0e-yield
> USRYIELD 180. 0.0 36. 100. 0.0 203. &
> USRYIELD 176. PHOTON -31. VAC2 VAC1
> 1.0p-yield
> USRYIELD 180. 0.0 36. 100. 0.0 203. &
> USRBDX 99. PHOTON -41. VAC2 VAC1 1.p-bdx
> USRBDX 1E-4 1E-7 1000. 6.28 0.0 3. &
> USRBDX 99. ELECTRON -41. VAC2 VAC1 1.e-bdx
> USRBDX 1E-4 1E-6 100. 6.28 0.0 3. &
> * Set the random number seed
> RANDOMIZ 1.0
> * Set the number of primary histories to be simulated in the run
> START 10000.
> STOP
>
> --------------------------------------------------
>
Received on Sat May 03 2014 - 13:03:45 CEST