Message: Re: Optical Photons not getting reflected from Auminium. Not Logged In (login)
 Next-in-Thread Next-in-Thread
 Next-in-Forum Next-in-Forum

Feedback Re: Optical Photons not getting reflected from Auminium. 

Forum: Processes Involving Optical Photons
Re: Question Optical Photons not getting reflected from Auminium. (Ashwath Rao)
Re: Feedback Re: Optical Photons not getting reflected from Auminium. (Ashwath Rao)
Re: Feedback Re: Optical Photons not getting reflected from Auminium. (Athreya Shankar)
Re: Feedback Re: Optical Photons not getting reflected from Auminium. (Ashwath Rao)
Date: 04 May, 2012
From: Athreya Shankar <Athreya Shankar>

Hello Ashwath,

I have a question here: Why do you plot sum of photon energies per gamma event? Shouldn't the plot be number of photons produced per gamma event?

Regarding the reflective layer, to define a reflective surface, it is sufficient to set the properties that you want (either through logicalbordersurface or logicalskinsurface) to the surface that you want. For example, suppose you want to wrap your scintillator with an aluminium wrapper. Then you do not have to define an Aluminium layer. All you have to do is set the desired surface properties (dielectric_metal, polished, etc.) to the surface between the scintillator and the experimental hall. Please refer the Geant4 Application developer's manual for syntax regarding logical border surfaces, etc.

I use ROOT along with GEANT for data analysis like histogram plotting, etc.

Regarding the Compton effect, my guess is that, the problem is not the dimensions of the detector (I may be wrong). I have a couple of suggestions:

1. For a start, I would suggest you use a pre-defined physics list that satisfies your purposes, and register optical physics processes along with it. That way, you don't have to worry about what to include and exclude from the physics list.

2. As i said earlier, the energy deposited spectrum obtained from geant4 is an ideal spectrum that does not take into account the intrinsic resolution of the detector. So, plot a graph of energy deposited in the detector per gamma event, without involving optical photons (that is, directly retrieve energy deposited without using optical photons), and see if you get a very sharp peak at the energy of the gamma particle incident. Do not sum the energy deposited by the optical photons, as optical photons are produced in Geant without energy conservation.

Most likely you will get an ideal spectrum with a very sharp peak. To make the spectrum resemble a typical experimentally obtained spectrum, you have to "smear" the spectrum using a "detector resolution".

Hope this helps,

Regards, Athreya

 Add Message Add Message
to: "Re: Optical Photons not getting reflected from Auminium."

 Subscribe Subscribe

This site runs SLAC HyperNews version 1.11-slac-98, derived from the original HyperNews