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alcap-org / g4sim

Simulation toolkit based on Geant4 and ROOT
http://wuchen1106.github.io/g4sim/
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GeSpectrum Data vs MC: A Few Questions #40

Open AndrewEdmonds11 opened 9 years ago

AndrewEdmonds11 commented 9 years ago

So I have a plot of data (blue) vs MC (black) for all photons (i.e. no time bins): gespectrum_datavsmc_all

Obviously, the main difference is that there is a large hump in the data and a massive peak below 10 keV. Where does this hump come from? Is it just in the detector response or is it from backgrounds that aren't simulated in the MC?

Currently, my plan is to just plot above 10 keV since these photons aren't important and to find a way to subtract the hump. Is it OK to just do a fit to the hump and subtract it?

Also, John do you have the number of muons that the data corresponds to from the muSc counter? Is this the 3.9e8 that you show in elog:187?

jrquirk commented 9 years ago

The bump shows up in beam off. I think it's background. The peak at ~zero energies I imagine is a mixture of electronic noise and regular xray background, but honestly I haven't thought about it.

The number of muons is what you say, as this is the entirety of the Al50b dataset.

And for fitting the hump, I just used TSpectrum::Background. It gives a nice smooth BG spectrum. You might want to use more than the default 20 passes to get rid of some of some of the peaks in the BG. The shape I'm not sure what it is.