I am currently working on calculating the neutron energy spectra resulting from 215 MeV protons impinging on a iron target. Specifically, I am interested in obtaining the Fluence(cm^-2 sr^-1 per primary) as a function of energy within an angular range of 0–15°.
To achieve this, I am using USRTRACK to score the fluence within the region and USRBDX to score the fluence at boundary. However, the resulting spectra do not show the expected high-energy neutron fluence peak, which is typically observed, as described in Scoring_II_Differential_spectra for forward angle, slide 13. The peak is either missing or significantly suppressed in my results.
I have attached the input file for your reference. I would greatly appreciate any guidance on how to resolve this issue and ensure that the high-energy component is correctly captured.
thank you for your question and for the input file, but is this the same input you used to obtain the plot you are showing?
The doubts I have relate to:
You are interested in the neutron spectrum coming from a 215 MeV proton beam impinging on a Fe target. But in the input, the proton has an energy of 250 MeV and the target is made of Cu.
With USRTRACK you cannot score the double differential distribution of neutrons. You can do it with the use of USRBDX as you are already correctly doing.
In the plot you show, the title says proton ion 215MeV on tissue target, so is this a neutron or proton spectrum?
Looking at the example in the scoringII lesson, in slide 13, a spectrum of HAD-CHAR is shown (therefore clearly not including neutrons) for a proton beam of 3.5 GeV impinging on a water+Al+Pb target. I don’t think you should use this as guidance for your results.
I suggest to try the exercise related to the scoringII lesson to understand the settings needed to obtain your desired quantities and the different approaches you can use.
