A method for calibrating and/or testing a liquid scintillation counter using an electronic test source, the method comprising: (a) generating, from a pulse light emitting diode of the electronic test source, a plurality of emulated radioactive event test pulses, wherein each emulated radioactive event test pulse is of a kind selected from the group consisting of: a beta test pulse having a light pulse shape that emulates a light pulse shape produced by a scintillator as a result of radioactive decay of a beta emitter; an alpha test pulse having a light pulse shape that emulates a light pulse shape produced by a scintillator as a result of radioactive decay of an alpha emitter; and a gamma test pulse having a light pulse shape that emulates a light pulse shape produced by a scintillator as a result of radioactive decay of a gamma emitter, wherein the plurality of emulated radioactive event test pulses comprises at least one beta test pulse and at least one alpha test pulse; and (b) detecting, by one or more detectors of the liquid scintillation counter, the plurality of emulated radioactive event test pulses; wherein: the plurality of emulated radioactive event test pulses comprises at least one gamma test pulse, and the method comprises calibrating one or more discriminators of the liquid scintillation counter based on (i) detection of the at least one alpha test pulse and/or the at least one beta test pulse and (ii) detection of the at least one gamma test pulse. (a) generating, from a pulse light emitting diode of the electronic test source, a plurality of emulated radioactive event test pulses, wherein each emulated radioactive event test pulse is of a kind selected from the group consisting of: a beta test pulse having a light pulse shape that emulates a light pulse shape produced by a scintillator as a result of radioactive decay of a beta emitter; an alpha test pulse having a light pulse shape that emulates a light pulse shape produced by a scintillator as a result of radioactive decay of an alpha emitter; and a gamma test pulse having a light pulse shape that emulates a light pulse shape produced by a scintillator as a result of radioactive decay of a gamma emitter, wherein the plurality of emulated radioactive event test pulses comprises at least one beta test pulse and at least one alpha test pulse; and a beta test pulse having a light pulse shape that emulates a light pulse shape produced by a scintillator as a result of radioactive decay of a beta emitter; an alpha test pulse having a light pulse shape that emulates a light pulse shape produced by a scintillator as a result of radioactive decay of an alpha emitter; and a gamma test pulse having a light pulse shape that emulates a light pulse shape produced by a scintillator as a result of radioactive decay of a gamma emitter, (b) detecting, by one or more detectors of the liquid scintillation counter, the plurality of emulated radioactive event test pulses; wherein: the plurality of emulated radioactive event test pulses comprises at least one gamma test pulse, and the method comprises calibrating one or more discriminators of the liquid scintillation counter based on (i) detection of the at least one alpha test pulse and/or the at least one beta test pulse and (ii) detection of the at least one gamma test pulse. the plurality of emulated radioactive event test pulses comprises at least one gamma test pulse, and the method comprises calibrating one or more discriminators of the liquid scintillation counter based on (i) detection of the at least one alpha test pulse and/or the at least one beta test pulse and (ii) detection of the at least one gamma test pulse.