I want to calculate the dose by photons in a BNCT facility. I checked the manual and saw that DOSE-EM is used to calculate the dose by electromagnetic radiation. I also read some discussion regarding this topic [1].
In my simulation, I calculated four quantities on the same sample:
gamdose: by DOSE-EM = 7.78e-9
totdose: by DOSE = 1.21e-8
phodose: DOSE + AUXSCORE photon = 1.8e-12
elecdose: DOSE + AUXSCORE electron = 4.77e-9
From that link that I attached before, the difference between gamdose and phodose may come from the EMFCUT: whether the dose is attributed to electron or the leading particle.
My question is, is it correct to calculate the photon dose by DOSE-EM? Actually, I want some confirmation because no one in the forum has brought this topic and I have never seen this on lectures.
1-in order to compare the different results, you should also indicate the uncertainty to be sure that the results are or aren’t compatible.
2-DOSE-EM accounts for the dose imparted by photon AND electron AND positron together.
3-In your input file there is no USRBIN/AUXSCORE for the electrons, therefore it’s not clear if you used this input to estimate your quantity #4 “elecdose”.
can you please comment on physis you want to estimate wit the dose delivereb by phonots.
I would say that DOSE-EM is the closest possible approximation, that can be achieved with FLUKA, nevertheless it is not that direct. As Amario wrote, DOSE-EM is combination of photon, electron and position energy deposition. This is due to dose diversity of dose deposition processes. In meaning of delivery of energy per mass, photons do not depose dose directly, but emits electrons by ionization and also induce photo nuclear reactions, product of which are then captured, which dissipates and absorbs energy.
Nevertheless if goal is to separate sources of radiation e.g. photons from neutrons, than selective transport threshold can be used.
For the uncertainty, I got around 1% so I’m sure they are all from different quantities. I have put the revised input as last time I upload the input which had been edited. Recently, I have run once more and I got the following:
gamdose (DOSE-EM) = 5.258e-9
totdose (DOSE) = 1.127e-8
elecdose (DOSE + AUXSCORE electron) = 4.314e-9
posidose (DOSE + AUXSCORE positron) = 9.432e-10
And as you said, the value in DOSE-EM corresponds to the sum of electron and positron dose (the “photon” dose is on the order of 10^-12). So, I think this one is solved.
I am simulating a beam shaping assembly for a BNCT facility, in which I have scored the neutron and photon spectrum. The photon spectrum spans up to 9 MeV, although the majority is below 1 MeV. The reference from IAEA says that I should measure the dose delivered by gamma rays when the neutron beam is on. The main objective is to quantify dose that is delivered not from neutron-boron reaction.
In reality, as you have explained, the “photon” dose is delivered by secondary electrons. In my case, the probability of photonuclear reactions is very small. So, I deduce that electronic shower alone is responsible for the dose calculated by DOSE-EM.
than yes, DOSE-EM is dose delivered by photons and secondary electromagnetic shower.
It separates target neutron/alpha dose deposition from secondary photon delivered dose. Discrepancy between photon dose (EM) and EL + POS dose is less than statistical error. In theory, there are “pure photon” absorption processes related to vibrational/rotational and Rydberg states excitation, but they are totally irrelevant for your case. Same as photonuclear processes below 9 MeV are negligible.