SELECTIVE RESONANCE IONIZATION OF ODD CALCIUM ISOTOPES USING LINEARLY POLARIZED LASERS

Abstract

Resonance ionization spectroscopy using narrow linewidth (~MHz) continuous wave lasers is an effective tool for element and isotope-selective measurements of trace radionuclides such as Calcium-41 (⁴¹Ca). In this study, triple (422.8 nm – 1034.7 nm – ~630 nm) and double (422.8 nm – ~390 nm) resonance ionization schemes of atomic Ca were developed, aiming for the separation of odd isotopes by (i) laser polarization-dependent selection rules, and (ii) large isotope shifts of odd Ca isotopes in the Rydberg levels. The measured ion yields of naturally occurring ⁴⁰Ca and ⁴³Ca were compared to estimate the separation factor of odd isotopes from ⁴⁰Ca. Our spectroscopic approaches could be a promising technique for the analysis of ⁴¹Ca in concrete waste from nuclear facilities, which will be investigated in the future.