Isc/G linearization

In the flash-tests measurements, the different irradiances are obtained by filters. The accuracy of the relative efficiency measurement is directly linked to the accuracy of the filter: an error of 1% on the filter calibration leads to an error of 1% in the relative efficiency.

This graph shows the ISC / G ratio, from these measurements.

We can see that the values are fairly well aligned, except at 100 W/m² which shows an overperformance of nearly 4%. This has a big impact on the low-light adjustment, by pulling the low-light efficiencies up.

We can evaluate irradiance measurement errors by assuming that Isc is approximately proportional to irradiance. The Linearize Isc/G button will adjust the GRef of each measured point to achieve a perfectly linear Isc/G ratio. In this example, this will define a GRef of around 104 W/m² for the first point.