Optimization of an electron cold cathode tube for soft X-ray spectrometry

The electron cold cathode tube for soft X-ray spectrometry was optimized. T herefore, the use of different cathode materials (aluminium, titanium and s teel) was investigated with respect to the produced plasma and its discharg e conditions. The current/voltage characteristics for different materials a nd electrode distances were measured in dependence of the operating pressur e. In addition the intensities and spectral properties of the generated sof t X-rays of a steel sample were compared and the sputtered surfaces of the cathodes were analysed by scanning electron microscopy (SEM) and atomic for ce microscopy (AFM). It was found that aluminium cathodes yield high intens ities of analytical lines, while the discharge can hardly be kept stable. T itanium cathodes produce a stable discharge over a long period of time and are very suitable for practical work. (C) 2000 Elsevier Science B.V. All ri ghts reserved.