ULTRATRACE ANALYSIS OF CALCIUM WITH HIGH ISOTOPIC SELECTIVITY BY DIODELASER RESONANCE IONIZATION MASS-SPECTROMETRY

A resonance ionisation mass spectrometer for the ultratrace determinat ion of calcium isotopes is presented. It achieves high overall efficie ncy, ultra-high isotopic abundance sensitivity of more than 10(10) and complete suppression of isobars. The system can be used for isotope r atio studies on stable and long-lived trace isotopes with the final go al of radiodating via Ca-41-determination. For the different applicati ons optical one-, two-or three-step resonance excitation and subsequen t ionisation is applied using simple and inexpensive diodelasers. Addi tional mass analysis is accomplished in a commercial quadrupole mass s pectrometer. The experimental set-up and first results on synthetical and meteorite samples are described.