Spectral changes of solar simulator xenon flash bulbs over lifetime and its effects on measurement uncertainty

The effects of lamp age on the spectral output of solar simulator xenon flash lamps and spectral output measurement uncertainty on the spectral mismatch are investigated. It is demonstrated that the spectrum of an older lamp set has a relatively lower blue and larger red content compared to a new set of bulbs. Measurements over the life-time of several sets of bulbs showed large unexpected variations due measurement uncertainty in spectral measurements themselves. The main influencing factors are investigated and a faulty temperature control is found to be the main source of uncertainty. It is shown that this alone can affect the mismatch calculation to a larger degree than the MMF would correct in itself.