Hello,
I have a proton beam and an array of detectors (optical fibres, in this case) I want to know the number of protons from the beam that interacted with each optical fibre.
What is the best way to do this?
Thank you,
Duarte
Dear Duarte,
You can get the number of beam particle collisions at each detector (region) by means of the USRBIN card. Setting WHAT(1) = 2, the USRBIN will provide the number of nuclear reactions in each region per primary event. Then set WHAT(2) = BEAMPART or PROTON depending on whether you want to account for the primary proton interacting in the region only (BEAMPART) or any proton, including secondary protons from further interactions. You can store the results for all detectors in the same output file if the regions are defined consecutively. Please check the information related to USRBIN in the manual.
This configuration provides the number of nuclear interactions in a region. For other kind of interactions, for instance continuous energy loss in a region, there is no interaction built-in score.
If you need additional information, do not hesitate to come back to us.
Kind regards,
Marta
Thank you for your response, Marta,
Is it possible to get the number of protons that simply entered the region? By your answer I guess not… But, just to be sure…
Thank you once again,
Duarte
Dear Duarte,
Yes, you can get the number of protons entering each region by setting either the USRYIELD or the USRBDX card.
In both cases, you will be interested in the integral number in the scoring output file for each detector. Do not forget that the result is given per primary and per range of each of the variables involved, i.e., in order to extract the number of protons entering the region, take the integral and multiply it by your beam intensity and the range of each variable, which is written in the scoring output file as well.
As suggestions for USRYIELD you can set WHAT(1)=101 and for USRDBX use WHAT(1)=1, you can keep the default ranges for the variables. Then select the two regions in contact that define the boundary where you want to get the number of protons crossing that boundary. Once more, if you are only interested in the protons from the primary beam use WHAT(2)=BEAMPART instead of PROTON.
Kind regards,
Marta
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Dear Marta,
Thank you for your answers.
I have tried USRBDX and it works, thank you. But, USRYIELD always gives me an error in the simulation.
The .out file gives me:
Error: “path/fluka4-0.1/bin/fluka” executable returned RC=136
Do you have an idea why this happens?
Thank you,
Duarte.
Can you share your USRYIELD card? Most likely you have an input error.
Dear Duarte,
The problem seems to be the definition of the “kind” of quantity you are asking for. Now, you have selected the double differential cross section that needs the “material” definition. You can change it for “ d2 N / dx1 dx2” that is the plain double differential yield. You are also missing the “Name” of the detector in the card. Just for good practice, even if by default they will be taken from the beam definition card, specify the energy limits and sent “Nbins1=1”.
Kind regards,
Marta
Thank you, Marta
That solved it.
Kind regards,
Duarte