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None Energy-dependent refractive index not simulated properly 

Forum: Processes Involving Optical Photons
Date: 26 Feb, 2016
From: Paola Ferrario <Paola Ferrario>

Hi, I'm finding a strange behaviour for optical photons propagating in a medium with refractive index dependent on the photon energy. My optical photons have an energy of 7 eV and propagate in the medium with one step of 25 mm. The time it takes for each photon to cover the step is step->GetDeltaTime(), is that correct? If I multiply this time for the speed of light in vacuum and divide for the distance (25 mm) I expect to find the refractive index geant4 is using to propagate the photon, is that correct? I find the correct refractive index if I set it constant for every energy of the photons, but I find a wrong one if I specify a dependence on the energy.

Specifically, I'm defining the following values for RINDEX:

Energy (MeV) refr index

1e-06, 1.36904

2e-06, 1.37846

3e-06, 1.39552

4e-06, 1.4229

5e-06, 1.46631

6e-06, 1.5399

6.2e-06, 1.56114

6.4e-06, 1.58587

6.6e-06, 1.61513

6.8e-06, 1.6505

7e-06, 1.69447

7.2e-06, 1.75124

7.4e-06, 1.82865

7.6e-06, 1.94333

7.8e-06, 2.13902

8e-06, 2.58866

8.2e-06, 7.06537

8.21e-06, 9.97887

and I get n = 3.44, while I would expect something near 1.7. If I define RINDEX = 1.7 for every energy in that range, I obtain n = 1.7 from the time of the step.

I'm a bit puzzled, what could be going on?

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1 Disagree: Re: Energy-dependent refractive index not simulated properly   (Gumplinger Peter - 26 Feb, 2016)
(_ None: Re: Energy-dependent refractive index not simulated properly   (Paola Ferrario - 26 Feb, 2016)
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