--- *Lars Fredrik Fjæra* On Mon, Oct 17, 2016 at 11:34 AM, Franz Siegfried Englbrecht < Franz.Englbrecht_at_physik.uni-muenchen.de> wrote: > Dear Lars, dear FLUKA Users, > > I want to adress only the question of 'So where are these CORRFACT cards?' > > You can, on a linux machine, adress the ASCII content of the binary .vlx > file by typing 'strings FILE.vlx'. There you will find the automatically > generated cards. > > Best, > Franz > > > > Quoting Lars Fredrik Fjæra <lfj049_at_student.uib.no>: > > Dear FLUKA users, >> >> I have two problems I want to address. >> >> First, is there an error in the Flair Dicom/Voxel tab? The unit range on >> the far left specifies Hounsfield units "less than" (<), however, when I >> was using artificial CT-scans, I noticed that Flair applies materials >> according to units of "less or equal" (<=). As an example, I have the >> following defined: >> >> < Unit Material Crho_min Crho_max >> 1000 HU<1000 0.9810 1.0168 >> 1100 HU<1100 0.9852 1.0144 >> >> In my CT scan I have only two Hounsfield units, HU=1000 and HU=-1000. >> Using >> the HU=1000 as an example, it should, according to Flair, be assigned the >> material called HU<1100 considering that 999<HU1000<1100. However, the HU >> of 1000 gets assigned the material HU<1000. This then means that the unit >> specification in Flair should be (=<). I have also noticed that this was >> the case in previous versions in Flair referring to for example the image >> in the manual. I have also attached images of my voxel/geometry setup to >> further illustrate the problem. The same also happens for my HU=-1000. It >> gets assigned the material HU<-1000 specified with the unit <-1000, where >> it really should be assigned the material HU<-1010. >> >> Next problem. I really miss a proper explanation/documentation of the >> stopping power calibration in the voxel tab. Performing the density >> calibration (Crho_min and Crho_max) is straight forward and works >> perfectly. I am however struggling with dE/dx calibration. First off, it >> is >> specified that the dE/dx correction are relative corrections. Relative to >> what? According to the manual, "dE/dx is applied relative to the >> correction >> of density (negative WHAT(1) in CORRFACT)". However, I was under the >> impression that if you perform the calibration in the .vxl file itself, >> you >> don't need any separate CORRFACT cards? The manual also states: >> "CdEdx_rel_min: relative correction factor on dE/dx for the minimum unit >> in the range CdEdx_rel_max: relative correction factor on dE/dx >> for the maximum unit in the range". So then I wonder, is the correction >> applied to the density corrections? I.e. If I have rho = 1, and Crho_max = >> 1.5 and CdEdx_rel_max = 1.5, the effective density for the stopping power >> will be 2.25? >> Further, from the FLUKA course slides about medical application, there is >> a >> sentence that states "FLAIR automatically appends the CORRFACT cards >> calculated taking into account the calibration curves provided by the user >> at the end of the .vxl file." So where are these CORRFACT cards? >> And to add to all this, I have been playing around with the CdEdx_rel_min >> and CdEdx_rel_max, just trying to change them to see if I can obtain some >> difference in the simulated ranges for Bragg peaks. However, I can apply >> whatever value to CdEdx_rel_min and CdEdx_rel_max, and still obtain >> exactly the same curves. I've even tried to obtain an error in my >> simulations by setting the CdEdx_rel_min and CdEdx_rel_max beyond the >> range [2/3,3/2], however the simulation runs fine. I did the same thing >> for >> the Crho_min and max, where I successfully obtained an error. So it seems >> that FLUKA doesn't even take into account my input to CdEdx_rel_min and >> CdEdx_rel_max. On the other hand, I am perfectly able to apply >> corrections >> using regular CORRFACT cards. Can someone please explain thoroughly how to >> properly use CdEdx_rel_min and CdEdx_rel_max? >> >> Thank you! >> >> --- >> *Lars Fredrik Fjæra* >> > > > >
(image/png attachment: Flair_unit_specification.png)
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