Separation of manganese isotopes by resonance ionization mass spectrometry for 53Mn half-life determination

Abstract

We report on the production of ultra-pure samples of the long-lived radioisotope 53Mn for precision measurements of its half-life. Activated samples from a copper beam dump from PSI, which was irradiated with 590 MeV protons, were used for extraction of the manganese fraction. Following initial radiochemical purification, efficient three-photon laser resonance ionization of manganese inside a hot-cavity laser ion source was applied for subsequent isotope selection in a 30 keV high transmission magnetic mass separator. A new ionization scheme was developed and characterized for 53Mn implantation. In this way the isobar 53Cr and the Mn isotopes 54,55Mn are quantitavely removed, with a special focus on the radioactive 54Mn isotope. Microgram quantities of 53Mn were implanted into Al targets with an isotopic and isobaric purity of well above 103. An overall efficiency of the enrichment process of about 15% was demonstrated.