Re: energy absorption coefficients

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User Domingo Granero wrote:

>> I am working in the field of Radiotherapy using G4.
>>   I have a technical problem in accessing information in G4
>>   that I don't know how to resolve it. 
>>   The question concerns the fact of how to access the photon 
>>   interaction coefficients in G4. 
>>   In our study we use variance reduction techniques to estimate kerma 
>>   in water. For this study we need the energy absorption coefficients 
>>   mu_en.
>>   Do you know how can we obtain this data in G4?
>> 
>>   Thanks in advance.
>>   --
>>

Each process (GammaConversion, Compton, PhotoEffect, Rayleigh) is treated independently. For each of them the input is cross section per atom and mean free path. Never G4 use the concept of total cross section nor interaction or absoption coefficients. Therefore to compute them, adds the individual cross sections or perfoms a simulation and extract it from a fit.