Hello
1) USRBDX: the code crashes because the minimum and maximum energy values
are both set to zero. This results in a division by a zero-value interval.
It is true, the manual states that the max value is set by default
equal to the beam one, but in case of an "ISOTOPE" beam, there is no beam
energy to refer to.
We'll protect this condition and amend the manual.
If you enter a value for the max energy (what(1) of
the continuation card), it will work. You can always check the URSBDX (and
other) settings in the .out file.
2) Indeed, the code crashes because of too many geometry errors. This is
due to small, but dangeous enough, mismatches between the "basic" cell and
the lattice ones:
the rotations defining the lattices are given in fixed format, filling the
10-digit field: this causes a difference between positive and
negative rotations. More than this, the overall width of the basic
cells, defined by two planes input with full precision, does not
match exactly the rotation steps.
There are different ways out: either use a more "round" angular step, to
avoid variations of the last available digit, and
adjust correctly the basic planes. Or, use free format for the rotations
to keep full precision. Or, use the native Fluka expressions, that keep
the double-precision down to the interpreting routines.
(I tried the first, by hand, it works)
regards
Paola
On Tue, 2 Jun 2020, Bartkoski,Dirk Alan wrote:
>
> I have a model that utilizes Iodine 125 seeds in a Gamma-Knife type geometry
> to produce a localized dose. I have modeled this in FLUKA with a row of
> collimating holes which has been replicated using LATTICES. I simulate the
> multiple simultaneous seeds by simulating each individual seed location and
> combining the results.
>
>
>
> I have two problems:
>
>
>
> 1) I am trying to score the photon current passing into the interior of
> my irradiator from the collimating holes. Implementing the USRBDX card to do
> one-way Current scoring causes the simulation to fail with
>
>
>
> Program received signal SIGFPE: Floating-point exception - erroneous
> arithmetic operation.
>
>
>
> I have been unable to identify the error.
>
> If I run the simulation with only USRBIN scoring it runs just fine.
>
>
>
> 2) When I use a seed location in one of the lattice regions, I get lots
> of
>
>
>
> Geofar: Particle in region 29 (cell # 5) in position -3.055184254E+00
> 6.866332986E+00 -3.308096656E+00
>
> is now causing trouble, requesting a step of 1.675802152E+03 cm
>
> to direction -2.521430795E-02 -7.443458025E-01 6.673181887E-01, error
> count: 0
>
>
>
> type errors. From what I understand this is lattice related and probably
> numerical precision related.
>
>
>
> I am at a loss as to how to fix these issues. I have attached my .flair
> (made with Flair3) and my input file.
>
>
>
> Any suggestions would be greatly appreciated.
>
> ___________________________________________________________________________
> ____
>
> Dirk A. Bartkoski, Ph.D.
>
> Research Scientist | Division of Radiation Oncology
>
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>
> T. Boone Pickens Tower (FCT8.5007)
>
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>
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>
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>
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>
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Received on Thu Jun 04 2020 - 20:01:51 CEST