FLUX MEASUREMENT FOR X-RAY PHOTOELECTRON-SPECTROSCOPY

A simple modification of a commercial aluminum anode x-ray source allo ws for the direct measurement of the x-ray flux. The modification invo lves a biased wire after the Al filter used to block the bremsstrahlun g radiation. The current collected by this wire was measured to be log arithmic in bias voltage but linear in power supply setting. The colle ctor wire was used to monitor the x-ray flux over a period of approxim ately 1 yr and shows the degradation of the flux due to anode contamin ation. Using the measured x-ray flux platinum photoelectron spectra we re normalized to within 20% over a 1 yr period and to 2% over a 1 week period. (C) 1995 American Institute of Physics.