Scoring LET from secondary particles of carbon ion radiotherapy

Dear FLUKA experts,

I’m trying to score LET distribution of primary and secondary particles in a water phantom (with incident carbon ions).
I used fluscw.f and GETLET function to obtain the LET factor.
I found that when a secondary particle with ID<-6, AM(JTRACK) does not work. In this case, instead I used pheavy(-JTRACK) and tkheav(-JTRACK) to obtain the momentum and kinetic energy of the current particle. And then used


to obtain the LET factor.
I’d like to confirm whether the above treatment is correct.

Moreover, when I print ETRACK and PTRACK in this case (with JTRACK<-6), ETRACK is always equal to AMNHEA(-JTRACK), which is the mass of the current particle, and PTRACK is always zero.
I’m thinking that when dealing with heavy ions (JTRACK<-6), only JTRACK works to reveal the particle ID, and one should ONLY obtain the kinetic energy and momentum of the current particle from tkheav(-JTRACK),pheavy(-JTRACK). Is it correct?

plus, to my understanding, I also have to consider the case of JTRACK >200, here I only have to substitute JTRACK with J0TRCK and use the “normal” way as shown in the figure below

I have attached my .inp and fluscw.f files.

Thank you very much!

carbonPeak.inp (1.1 KB)
fluscw_carbon.f (5.1 KB)

Dear @kwlibuaa,

I suggest you have a look at this post where the different ion codes are explained.

Particularly in your case, the concerning ions are those with IDs ranging from -7 to -12, which are ions whose initial kinetic energy is below the threshold and are therefore transported in a last step where their energy is fully deposited. Hence, when retrieving its information about kinetic energy/momentum from tracker, you will read 0.

As you point out correctly, if you want to retrieve their mass, initial kinetic energy and momentum you can use the functions AMNHEA(-JTRACK), TKHEAV(-JTRACK) and PHEAVY(-JTRACK).

Lastly, the particle codes larger than 200 are only generalised particle codes for scoring purposes. You should not find these values in the tracker.

I hope this helps


1 Like

Dear Mario,

Thanks a lot for your explanation!