I’m fairly new to Geant4, and so far, I have been able to calculate the gamma spectrum for thermal neutrons incident on a GAGG detector. Now, I need to determine the neutron fluence as a function of neutron energy using GAGG, but I’m not quite sure how to proceed.
I would truly appreciate any guidance on the following:
What would be the best approach to track and score neutron fluence in Geant4?
Which classes or commands should I use to obtain the neutron fluence spectrum?
Are there any built-in tools or example codes that might help with this task?
Any advice, resources, or insights you could share would mean a lot to me. Thank you in advance for your time and help!
Can you say a little more about GAGG (I’m not familiar with that).
But basically, in your sensitive detector ProcessHits, you have to count the neutrons in and out. Fluence is defined as the number of particles that enter a sphere of unit cross-sectional area. It can be shown that this is equivalent to the track length per unit volume. So sum the track lengths (position at exit - position at entry) and divide by the volume of your detector. (This ignores neutrons that interact. If that’s an issue, create a small test volume where you want to measure the fluence.)
The neutron fluence is defined by you, so you can trivially record the energy of the neutrons when they are produced, or when they hit your detector.
I need to determine the neutron fluence and a function of neutron energy using GAGG
So are you simulating scintillation, measuring the pulse height spectrum, and you want to use that to measure neutron fluence? That is less of a Geant4 question, and more of a deconvoluting the light yield per neutron, scattering effects, etc. But you can start by comparing the incoming neutron energy spectrum with the resulting pulse height spectrum