Method for determining an effective lifetime τ of the minority charge carriers of a doped semiconductor substrate by measurement of photoluminescent radiation under quasi-static measurement conditions, comprising the following method steps: A application of electromagnetic excitation radiation to the semiconductor substrate in order to generate photoluminescent radiation in the semiconductor substrate, the variation in the intensity of the excitation radiation over time being periodically modulated in such a way that the generation rate G of charge carrier pairs in the semiconductor substrate as a result of the excitation radiation has a maximum and a minimum during an excitation period and at least the relative variation in the generation rate over time G(t) being determined by means of time-dependent measurement of the intensity of the excitation radiation, B time-resolved measurement of the intensity of the photoluminescent radiation emanating from a measurement region of the semiconductor substrate, the variation in the intensity of the photoluminescent radiation over time Φ (t) being measured at least during an excitation period, C determination of the effective lifetime τ of the semiconductor substrate on the basis of the measurement of the time difference between the maximum of the generation rate G(t) and the maximum of the intensity of the photoluminescent radiation Φ (t) , wherein the method steps A and B are executed, in respect of the excitation intensity, in a first measurement configuration which is selected in such a way that low-injection conditions are present in the semiconductor substrate, and in step C the effective lifetime τ of the minority charge carriers at the maximum excess charge carrier density Δ n max achieved during an excitation period is determined. A application of electromagnetic excitation radiation to the semiconductor substrate in order to generate photoluminescent radiation in the semiconductor substrate, the variation in the intensity of the excitation radiation over time being periodically modulated in such a way that the generation rate G of charge carrier pairs in the semiconductor substrate as a result of the excitation radiation has a maximum and a minimum during an excitation period and at least the relative variation in the generation rate over time G(t) being determined by means of time-dependent measurement of the intensity of the excitation radiation, B time-resolved measurement of the intensity of the photoluminescent radiation emanating from a measurement region of the semiconductor substrate, the variation in the intensity of the photoluminescent radiation over time Φ (t) being measured at least during an excitation period, C determination of the effective lifetime τ of the semiconductor substrate on the basis of the measurement of the time difference between the maximum of the generation rate G(t) and the maximum of the intensity of the photoluminescent radiation Φ (t) , wherein the method steps A and B are executed, in respect of the excitation intensity, in a first measurement configuration which is selected in such a way that low-injection conditions are present in the semiconductor substrate, and in step C the effective lifetime τ of the minority charge carriers at the maximum excess charge carrier density Δ n max achieved during an excitation period is determined. wherein the method steps A and B are executed, in respect of the excitation intensity, in a first measurement configuration which is selected in such a way that low-injection conditions are present in the semiconductor substrate, and in step C the effective lifetime τ of the minority charge carriers at the maximum excess charge carrier density Δ n max achieved during an excitation period is determined. <EOS>