The influence of the conversion of pump light of wavelengths below 400nm into pump light with a central wavelength of 500nm in a Europium doped quartzglass pump chamber has been investigated. The results are compared to the ones from an undoped quartzglass. The measurements resulted in a reduction of the slope efficiency by a factor of two for the doped quartzglass compared to the undoped one. Furthermore, the pump-pulse lengths around 80μs lead to a decrease in the slope efficiency compared to pump-pulse lengths above 100μs.