I am a beginner on fluka and I intend to calculate mass attenuation coefficients for a cylindirical glass composite (my target-in a RPP body (at the origin)) from a photon beam (20 cm away from the left side of the glass samples) towards to detection region (a cylindirical NaI detector with covered by MgO and Al).
In my input file, I will run this geometry from 100 keV to 15 MeV for 0.2 cm thick sample seperately for my each energy step. Should I run this geometry for different sample thickness with every energy step seperately as well?
I use USRTACK and USRBIN cards for scoring. I do not know what to put for NR, Nphi and NZ numbers?
In geometry tab, visuilasion is not clear.
Do I get output for I0 without glass sample in the geometry? input.txt (3.4 KB)
Could you please please control my input file for fixing before runing it.
Dear User,
I would suggest you severla improvements for your input file to get results needed to calculate mass attenuation coefficients. However, I will need some input for you to understed why are you using certain approaches.
Yes, to calculate coefficient for specific energies you have to run simulation for each energy. If you want to avoid programming I suggest you to set energz value using the DEFAULT card. Than you can run simulations for sevaral different energz values in parallel using various spawns in the Ran tab.
1.1) As you going to ran simulation for the wide range of energies concider to change target depth in a similar way to adjust it to the energy value.
What is the purpose of USRTRACK card in zour model? If you want to use Flair functions for visualisation of data, please save result as binaries (BIN) not ASCII (ASC) format. You can convert it after.
2.1) What is your purpuse to adjust thresholds levels in the physical model of Fluka usinf EMFCUT cards?
Thank you for your kind response. I am trying to calculate I/I0 transmission through the cylindiric NaI detector (7.62x7.62) dimensions with MgO and Al layers between 100 keV-15 MeV energies with different thicknesses. After finding I/I0, I am going to use Lambert–Beer law to find mass attenuation coeff.
Since I am a beginner, I decided to go with a simpler geometry and I designed an RPP glass sample (various thicknesses) with a photon beam for a specific energies (0.356, 0.662, 1.173 and 1.330 MeV) and use two Usrbdx card for the photon fluence scoring coming from the left to sample and the other one for the fluence leaving from the sample to the right region. However I still have errors around the regions that I defined and I could’t fix them.
I used the EMFCUT card with fudgem=1 for the secondary particles.
input2.txt (2.5 KB)
If you take a look to the input file I attached, I’d be grateful.
Dear Gulmen,
In this case, to measure I to I0, I would suggest, that you will score beam before and anfter target and evaluate the ratio. It is possible to use both USRBIN scoring to see beam ortogonal cross section or USRBDX to calculate photon flux through input and output surfaces of the target.
Also I would suggest, that the beam cross section will be significantly larger of soring area, to avoid geometry effect. Also it is up to your goals if you need EMFCUT card.
Otherwise, your model is functional, after you correct some minor errors:
define left region as: +spin +plane1, right as: +spin -plane2
Than distance between planes should be smaller, not larger that target area to overlap.
The last thing to correct is to set material density value for all oxides in your model.
I tried the regions like you indicated above but I still got errors in the viewports. They are just at the border of the spin at z=0 x=100 x=-100 and at the border of the spout.
So I changed the body. I used 4 infinite planes and I put my target at the intersection of those planes and I got errors at the XY planes shown on the x-z and y-z viewports. I still don’t understand why those errors on the XY-planes arise? And I got warning about multiple assignment for left and right regions although I just assiged these regions for once for each. And those regions are divided by the XY planes.
The other issue that you higlight is to chane the delta(x) and delta(y) from the BEAM card? Dou you mean I should increse those, like from 0.2 to 2 may be?
Dear Gulmen,
Try to take a look on my edition of your simulation number 2. I am not sure that it solves your task properly, but you can check how dose geometry works.
Yes, you may increse it like these or adjust to your need.
I did XY planes for -0.25 and 0.25 before then I got warning about target and planes are touching. Also still got viewport errors (around planes). That’s why I chose 0.26 for the planes. Still I couldn’t fix these viewport errors.
Would it be wrong If I run my input like this?
Dear Gulmen,
I see no errors in your input file.
Try to update geometry with reasonable zoom at each viewport. Also it can be usefull to create a new flair project and import your .inp file.