Spectral count defined

It is natural to compare the performance of an optimized spectrofluorometer with PMT detection and photon counting signal processing to a spectrofluorometer with IDA detection for routine quantitative measurements. Here the sum of the signals from a few diodes defines a spectral bandpass equivalent to that defined by a monochromator with PMT detection. With our system, some loss of detectability occurs in certain situations. 

An alternative option is to purchase a good quality commercial solar simulator. Various standards have been defined to evaluate the performance of solar simulators. The three main criteria are spectral matching, uniformity of irradiation, and temporal stability. The quahty with regard to each of these criteria is indicated by three consecutive letters. Table 3.5 shows the widely adopted American, European, and Japanese standards for these criteria. If a manufacturer conforms to all three standards, it is the strictest one that counts. For example, an ABB class solar simulator that conforms to aU three standards of Table 3.5 would have a spectral irradiance (W/m /nm) that deviates no more than —25% to +25% from the AM1.5G intensity within the entire wavelength range (usually 400-1,100 nm). The nonuniformity of the integrated irradiation intensity (W/m ) should be within 3% for every point inside the specified area (e.g., 2 x 2 in.), and the integrated irradiation intensity would vary less than 1% (rms) in time. A 2 x 2 in. class ABB solar simulator would do very nicely for almost all PEC studies. 

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