Charge measurement on radiation silicon detectors with poor SNR

Recently I came across the problem of having to precisely measure the charge produced by a PIN detector from the RD50 FBK TI-LGAD production. As we know, PINs have no internal gain and since this one is from the TI-LGAD production it is only 45 micrometers thick. Thus, the signals are really small and the Landau distribution partially overlaps with the noise, making it very difficult to precisely perform the fit. Fortunately, I came across with a method to actually perform the fit, which is probably a common technique for those doing their PhDs on data analysis but it is the first time I apply such kind of technique to LGADs (or PINs actually) so I want to keep a record of it. I developed this method while characterizing the gain of the new Chubut 2 board (soon more info ’bout it) but it will be useful when dealing with irradiated LGADs as well, since they tend to loose the gain.

Full screen version here.