How can I normalize an Energy Spectrum by solid angle?

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ROOT Version: 6.18
Platform: Ubuntu
Compiler: Not Provided

Hello to everyone,

I have some energy spectra in the center of mass reference system and I want to normalized them by solid angle. But I don’t know how to that. Someone can help me?


Hi Elisabetta,

I suppose you have the energy spectrum as an (eta, phi) or (theta, phi) distribution, or can you have the data that creates the spectrum? Normalization in solid angle is traditionally \Delta\theta * \Delta\phi, i.e. the bin sizes in phi and theta. Or, instead of theta, eta - check with whoever asked you to normalize.

If the histogram is (theta, phi) and normalization is in (theta*phi) and you have equidistant bins then you can simply scale your histogram by \Delta\theta * \Delta\phi, else you can create a histogram with identical bin layout (TH1::CloneEmpty()) and you fill it with the area for each bin, then you divide your energy spectrum by that area histogram. Makes sense?