Evaluation of low-count spectra without binning

When evaluating spectra measured by single-channel method, the usual approach is to re-sort them into some suitable energy bins and then to add together the items falling into one bin. Then a theoretical spectrum shape is fitted into this data set thus determining the wanted physical parameters. Such an approach, however, unavoidably suffers from a systematical error which, moreover, may not be easily estimated. To do away with this error, we suggest a method which avoids the binning at all.