Hello
are you makeing the particle start exactly on a boundary? if yes, this can
be the problem, try moving the starting point slightly.
Paola
> Dear FLUKA experts,
>
> As it is not possible to have geometry overlapping with the voxel cage
> in FLUKA, I ended up using phase space simulations to avoid the issue.
> In step one, I log the particles leaving the treatment nozzle.
> In step two, I continue simulating these logged particles from step 1
> using the source routine, and have them starting inside the voxel body.
>
> While the simulation runs and completes, and I also achieve identical
> results as for not using a phase space simulation (in this case I have
> to resolve to cropping the voxel body), there are a lot of outputs in
> the .err file stating the following:
>
> Geofar: Particle in region 4 (cell # 0) in position
> 2.910000000E+00 8.950000000E+00 -1.638000000E+01
> is now causing trouble, requesting a step of 1.000001378E+15 cm
> to direction -1.009910122E-01 7.409340598E-01 6.639409119E-01,
> error count: 0
> R2: 9.411195461E+00 R3: 1.889113549E+01 cm
> X*U (2D): 6.337475990E+00 X*U (3D): -4.537876147E+00 cm
> X*UOLD(2D): -1.526943017E+00 X*UOLD(3D): -1.724937373E+01 cm
> Kloop: 456154, Irsave: 1266, Irsav2: 1266, error code: -3
> Nfrom: 5000
> old direction 1.674280441E-01 -2.250456564E-01 9.598553550E-01,
> lagain, lstnew, lsense, lsnsct F F F F
> Particle index 7 total energy 5.600000000E-04 GeV Nsurf 0
> We succeeded in saving the particle: current region is n. 5 (cell
> # 0)
>
> As far as I can see, the position equals the start position of the
> particles. Region no 4 is the voxel cage. Region no 5 is the same region
> as where the particle starts.
>
> Is there an obvious reason for this to be happening? Shouldn't it be
> possible to start the particles within the voxel body?
>
> Best regards,
> Lars Fredrik Fjæra
> University of Bergen
>
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>
Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
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Received on Sun Jul 12 2020 - 17:22:35 CEST