[Gate-users] Digitizer modules for PMT, and quantum efficiency of PMT?

[Paweł Kowalski]

Hello Amy,

> I have realized that I need to account for the quantum efficiency of the PMT
> when doing these simulations. Initially I thought that by changing the value
> for EFFICIENCY in the detection surface definition in the Surfaces.xml file
> would be sufficient. Is this true?

Yes. You should change the value of EFFICIENCY in Surfaces.xml, but if
you want to simulate a concrete photomultiplier, you should define the
efficiency in function of energy of photons. Each producer of
photomultipliers give this dependencies.

> Secondly, when searching for ways to simulate PMT output, the idea of using
> the digitizer came up frequently. Initially I shied away from using the
> digitizer because I did not understand how to incorporate it or what format
> the output would even be. Has anyone used the digitizer and its modules to
> recreate the output of a PMT? Such that it includes quantum efficiency, and
> each 'pulse' represents the number of photons detected for a given parent
> particle?  If so, what would the output look like? Would this be something I
> could use to generate a simulated spectrum?

I do not use the digitizer module but I think that the simplest way to
have voltage signals from photomultipliers is writing a script in C
and combine information from Hits about time of arrival of photons to
photomultipliers with information about shapes of signals from single
photons.

If you will have any better idea, please let me know.

Best regards,
Paweł Kowalski