Quantitative X‐ray spectrometric analyses with a cold cathode tube attachment

Abstract

A CGR cold cathode tube for X‐ray anlysis of very light elements has been attached to a sequential Siemens XRF spectrometer. Economic consideraions justify a rapid changeover attachment rather than the purchase of a separate spectrometer which can be applied to a few elements. The essential conceppts developed for successful integration of the attachment with the spectrometer are described. An automic activated alumina trap system to remove backstreaming oil vapours was incorporated with the existing vacuum logic. The current stabilization circuit of the generator was redesigned in order to acheive quantitative analyses. The developed attachment has competitive applicability to the quantitative analyses of magnesium and lighter elements. For magnesium the cold cathode tube achieves a large deduction in both matrix absorption effects and high order spectral interferences when compared with a typical chromium tube.

X-ray spectrometry

“…A sequential simplex procedure for deconvolution is described in a separate paper (139). Russ (140) has broadened the scope of frame c with a different fluorescent yield expression to extend the energy range beyond [1][2][3][4][5][6][7][8][9][10][11][12] keV, and a different standardization procedure to allow different geometries and, if desired, no standards. He has also included the use of peak/background ratios to deal, at least partially, with finite particle size.…”

“…As mentioned above, electron columns of all descriptions with applied voltages up to 1 MeV (2) are now being used for excitation. The combination of X-rays and electrons represented by cold cathode X-ray tubes, usually windowless, is having some revival of interest (3)(4)(5), probably because of the continuing inadequacy in one way or another of almost every method devised for light element analysis. The conversion of either a scanning (6,7) or a transmission (8) electron microscope into an X-ray tube by insertion of a suitable target is also not an entirely original suggestion but the potential gain in signal-to-noise ratio is worth the reminder.…”

“…On the other hand, suggest that for medium atomic number elements, the cross-section maxima occur in the 20-50 MeV range. The use of argon ions up to 3 MeV is pointed out by Heitz et al (20) to induce preferentially X-ray emission below 3.2 keV and therefore to give enhanced ©…”