Dear FLUKA experts,
While using the attached input in FLUKA, I got some confusing results. In this, I am using two ROTDEFINI cards, namely, rot 1 and rot 2. rot 1 is used to transform a detector (det) and rot 2 is used to transform the bodies (aw and bw). I am performing scoring using DETECT card (along with DETGEB) and USRBIN. The source is 662keV photons given using BEAM card.
I have the following problems:

When I introduced dx, dy and dz in ROTDEFINI card for rot1, my simulation finished with errors. However, it worked well when I used rotation alone in ROTDEFINI (implemented using transform directives) and dx,dy,dz using start/end translat directives.

For rot2: What geometry viewer shows in the attached ‘sample.flair’ file is precisely what I am intending to make. However, the same geometry can be obtained in two ways;
a) Define translations of dx =18 and dy=20 using start and end translat cards
b) Define dx=18 and dy=20 in ROTDEFINI cards with zero rotation. I need to make a rotation of these bodies in further studies. That’s why I kept the ROTDEFINI card even if its angle of rotation is zero in the attached file.
Both a) and b) show same geometry in the viewer. In both cases, the beam position was also the same. However, USRBIN and DETECT scoring turned out to be quite different. I am attaching the USRBIN superimposed on geometry for the two cases. Why are the BEAMPART distribution different although the geometry looks same?
It will be really helpful if someone can explain me the difference.
Regards
Charubala
sample.inp (3.0 KB)
sample.flair (7.6 KB)