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Forum: Event and Track Management
Re: None Total Scintillation Events (Sean Jones)
Date: 02 May, 2007
From: Sean Jones <Sean Jones>

My compliments to Peter, the Gentleman that responded so quickly to my first post.

Here is a response to clarify the work I'm attempting to perform and a potential solution to my problem:

I am attempting to simulate the light capture efficiency of a phoswich detector.

In my output I am tallying optical photons that reach the Photomultiplier by events that undergo the transportation process at the PMT interface location, I believe I've narrowed it down to events with the energy column showing a value corresponding to that of the optical photon energy in eV (vice units of MeV for all other steps).

Where I get into trouble is that I have the following events that deposit energy in my output file.

LowEnCompt LowEnPhot eBrem eIoni msc

If I tally up the energy deposited by all of the events and multiply it by my scintillation yield, I would have an unreasonably low value for light capture efficiency (assuming I am properly counting photons that hit the PMT interface, I have reflectivity set to 0 and efficiency set to 1 for the PMT).

This lead me to look at what types of events I must add or subtract to get a dose value for to calculate the total number of photons generated. I am looking the possibilities for all types of events singularly. However, a type of interaction that yields a reasonable number does not apply to all simulations.

Because of this I came to think, it would seem to make sense that for beta particles, the sum of all msc events would yield the value for photons produced my the betas travelling through the medium. Where as for gammas, the sum of the LowEnPhot and LowEnCompt interactions would yield the value I am looking for.

I know I'm a neophyte to the code, and the GATE manual is unfortunately not written such a way that I could interpret the data output file for the scanner type of Sensitive Detector. I have referenced the GEANT4 manual as well, and what I believe I have in the data file is the time slice, the event ID, real event time, energy deposited, TrackLength, X, Y, Z, and process. I have fast analysis set on.

However, if energy deposited by all events is of concern, then Perhaps I am using the wrong column for energy deposited and mistaking it for something else.

What I am thinking now is that I may have mistaken TrackLength for energy deposited and energy deposited for remaining particle energy. Although that does leave me confused as to which column I have in the file for TrackLength. I will change the code I made to analyze the file and keep the thread updated as to my status.

Thank you all for reading. I suppose since I've recently learned C++, I will transition to using the whole framework for GEANT4 instead of utilizing it primarily through GATE.

Regards,

Sean

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