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## Re: One energy emission

Forum: Processes Involving Optical Photons
Re: One energy emission (Davit Mayilyan)
Date: 26 Aug, 2011
From: Gumplinger Peter <Gumplinger Peter>

 > 1. How can I configure wls so that after emission there be not a > spectrum of energies, but photons of one exact energy. You have to give the photon spectrum at, at least, two spectral points. > G4double PhotonEnergy[nEntries] = { 2.73*eV,3.0*eV}; These points can be as close together as you like to make them, for example: const G4int nEntries = 2; G4double PhotonEnergy[nEntries] = { 2.730*eV,2.731*eV}; G4double EmissionFib[nEntries] = {1.,1.}; ({ 1.0, 0.0} will NOT work as you expect) The '1' is a relative strength; e.g. you are not required to give the spectral intensity in absolute terms. It is not possible to have photons of only 'one exact energy' in the mathematical sense. ```> What is the max value that can be instead of 1.0? Can it be infinitly > large number? ``` Why would you want to specify a spectral intensity point with an infinitely large number? That's unphysical - but yes, the largest number you specify for the relative intensity can be larger than one (so long as the numbers you give are in the correct relation to each other and where you don't have any emission the spectrum goes to zero. Please, be reminded that for now the intensity sampling between spectral points is linear. You get improved sampling by specifying the spectrum at better more than less points. > 2. In the wls example, in the PrimaryGeneratorAction.cc there is a > sampledEnergy variable. What does it do? Assuming that you uncomment the line: //particleGun->SetParticleEnergy(sampledEnergy); the code would sample 'sampledEnergy' from the WLS spectrum you specified for PMMA and would launch an optical photon with that energy.

1 Re: One energy emission   (Davit Mayilyan - 31 Aug, 2011)
 to: "Re: One energy emission"
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