FLUX MEASUREMENT FOR X-RAY PHOTOELECTRON-SPECTROSCOPY

A simple modification of a commercial aluminum anode x-ray source allows for the direct measurement of the x-ray flux. The modification involves a biased wire after the Al filter used to block the bremsstrahlung radiation. The current collected by this wire was measured to be logarithmic in bias voltage but linear in power supply setting. The collector wire was used to monitor the x-ray flux over a period of approximately 1 yr and shows the degradation of the flux due to anode contamination. Using the measured x-ray flux platinum photoelectron spectra were normalized to within 20% over a 1 yr period and to 2% over a 1 week period. (C) 1995 American Institute of Physics.