Hi Sasha, in the link https://halldweb1.jlab.org/talks/2011-3Q/ADC%20spectra%20and%20Time-walk%20corrections_files/ you show an ADC spectrum of a paddle PMT: adc_l_par_nottrig.gif. what is the HV of the PMT set at and what type of ADC are you using? cheers, Beni