The determination of optical properties

Hi everyone.

I want to define the optical property of the scintillator. I don`t understand how to determine the FASTCOMPONENT and SLOWCOMPONENT array according to energy range.

How do I determine the value of the array, and what is the appropriate length of the array?

First, how many decay time constants does your scintillator have? If there is only one (or you don’t care about time of emission), you just need one of FASTCOMPONENT and SLOWCOMPONENT. (Note in Geant4 version 11 these become SCINTILLATIONCOMPONENT1,2,3.) It doesn’t matter which, but use the same pattern for all the material properties.

You can determine values of the array by digitizing the plot. The appropriate number of data points is that sufficient to reproduce the curve to the accuracy you desire.

Thank you, that helped me a lot.

there is only one component in the plastic scintillator that I need. I have read a lot of people’s question about FASTCOMPONENT. However, I still don’t understand what it really means. Decay time or Pulse Width(FWHM)? and How can I change the rise time of scintillator.

FASTCOMPONENT is the energy spectrum of the emitted opticalphotons. You can change the rise time wtih FASTSCINTILLATIONRISETIME.

This is documented here:

and there is a table of relevant properties: