Distinguish edep generated by different types of transportation and physics processes

Dear Fluka experts,
How can I distinguish energy deposition generated by different types of transportation or physics processes?
Input files have been uploaded. I scored the total edep within the TLD region, however, more interested in the edep composition of different physics processes.
For example:

  1. Energy deposited by collisionless electrons or bremsstrahlung photons (interaction with gold), no scattering occurred before they reaching TLD region);
  2. Energy deposited by bremsstrahlung photons produced by electron and pmma material;
  3. Energy deposited by other scattering photons.

Is there any similar mgdraw.f examples about this simulation. Any suggestions are appreciated.

input.inp (5.1 KB)

Dear @songhg19,

could you possibly provide more details about your study?
From the input, I see that you have a monochromatic 21 MeV electron beam that impinges on a 2 mm Au target. Downstream the target, there is a 40 mm PMMA block, which covers 3 TLDs made of Lif.

In the plot below, the electron and photon fluences out of the target and PMMA block are shown. As expected, out of the PMMA block, the electron fluence is highly reduced and it is dominated by photon fluence. Clearly “collisionless electrons” are highly unlikely.
Also, the other categories would be rather questionable as they are linked to transport thresholds and the complexity of the electrons and photons interaction mechanisms in each event.

In addition:

  • the body chamber_o has more than 8 characters.
  • in the USRBIN in unit 30, you are basically scoring ENERGY in vacuum
  • the scoring in the TLD regions is ambient dose (and not total energy as you mentioned)

Let us know if this can help

Dear Fluka expert,

I reconsidered and reedited my input file. The simulation, Like @luillo said, have a momonochromatic 21 MeV electron beam that impinges on a 1cm Au target. Downstream the target, there is a shielding module, consist of 40 mm PMMA block and Pb, Cu block. Within this module is 1 TLD made of LiF.
To get more data, dimension of TLD is rescaled.

Since highly energetic electrons generate Bremsstrahlung photons, I hope this module can as much as possible to stop electrons from depositing energy within the TLD, in the meantime, scoring the energy deposited by Bremsstrahlung photons generated by Au target.

I am trying to distinguish the contribution of photons if they are produced in different regions, namely the following 2 different processes:

  1. If a photon generated by Bremsstrahlung process of the primary electron and Au target, and the exact photon deposit energy within the TLD, without interactions with other material, then score the energy deposition within the TLD as edep1;
  2. If photons are generated elsewhere (for instance : PMMA), and also deposit energy within the TLD, score it as edep2.

I can not find similar examples. Could you please tell how to implement this thought?
Thanks in advance!
Here is my input and user routine :
input.inp (3.5 KB)
mgdraw_shh.f (16.9 KB)

Best regards,

Dear @songhg19,

the energy deposited in the TLD (and elsewhere!) is always deposited by electrons.
There is no energy deposited by photons unless they go below the transport threshold.

In particular, you can check that by filtering the energy deposited by photons in the TLD region with an AUXSCORE card (as in the USRBIN associated with unit 31 in the attached input file).
As said in my previous email, this depends on the transport cuts, which are 100 keV and 33 keV for electrons/positions and photons, respectively, for the default PRECISION, which - I think - are suitable for your application.
With the aforementioned transport cuts, the fraction of energy deposited in the TLD and attributed to the photons is ~0.01%.

The energy deposited by Bremsstrahlung photons entering the TLD without any interaction with other materials can be estimated with the usrmed.f to be activated by the MAT-PROP card (see how in the attached input file).
In the attached usrmed.f , all particles entering the TLD are killed, except the photons (IJ==7) of second-generation (LTRACK==2), which are Bremsstrahlung photons produced in Au target (where else otherwise?).
The fraction of energy deposited in the TLD by those photons is ~24%.

Of course, you can change the usrmed.f routine to kill the contribution of other particles at different boundaries. For example, the Bremsstrahlung photons exiting the Au target account for 44% of the total energy deposited in the TLD, while all photons exiting the Au target account for 98% of the total energy.

All that to stress what I had stated in my previous email:
For every single primary electron, Bremsstrahlung photons produced in the Au target will interact with different mechanisms in the other regions of your setup and, eventually, the energy deposited in the TLD is essentially due to electrons.

Hope this can help.

input.inp (5.7 KB)
usrmed.f (3.2 KB)

Dear @luillo

Thanks for your suggestions! This is more convenient than “two-step” method I am using.
As for my understanding, particles are killed (neither transported nor deposited !!!) if they mismatch the conditions :

IF ( LTRACK .EQ. 2 .AND. IJ .EQ. 7 )

I have 3 questions for your reply:

  1. Am I right about the understanding of command WEE = ZERZER , Neither transported nor deposited?
  2. Could you please explain more about the variable LTRACK? Dose it mean interaction times? Like the explanation in this post : Mgdraw.f on (n,p) reaction events?
  3. How to distinguish the primary particles and secondaries, which variable or user routine should we consider?

Again, thanks for your reply!

Best regards,

Dear @songhg19 ,

sorry for the belated reply.

Yes. It sets the particle weight to zero and when the thread returns to the routine which has called USRMED, the particle on the spot.

LTRACK is the generation number. It is incremented by one after any discrete process the particle may incur.
It is documented in include/trackr.inc.

Following the previous point, LTRACK=1 for a primary electron, while LTRACK=2 for a Bremsstrahlung photon produced by a primary electron.

Hope this could help.

Cheers, Luigi

Dear @luillo

Thanks for your help. Really appreciated!