99Tc in stars, reactors, and nuclear medicine

Abstract

The roles of 99gTc in stars and in nuclear fission reactors and that of 99mTc in nuclear medicine that were studied using neutrons provided from accelerators are reported. In addition to the critical role of 99gTc in stars, we also describe the roles of related light nuclei such as 16O, and experimental studies on keV-neutron capture cross sections of these light nuclei that were performed using keV neutrons provided from a 3.2-MV Pelletron accelerator are reported. The keV-neutron capture cross section of 99gTc, that is important in studies on the nucleosynthesis of 99Tc in stars and on the nuclear transmutation of long-lived nuclear wastes produced in fission reactors, were measured. The cross sections of both light nuclei and 99gTc were measured using a neutron time-of-flight method with a ns-pulsed neutron source from the 7Li(p,n)7Be reaction and with an anti-Compton γ-ray NaI(Tl) spectrometer. The measurements reported here were compared with the values of recent worldwide evaluated nuclear data libraries.We proposed a method of producing 99mTc from the 100Mo(n,2n)99Mo reaction, and performed a 99mTc production experiment using a natMo sample and MeV neutrons from the natC(d,n) reaction by 40 MeV deuterons at a cyclotron. Calculations for the 99mTc production with an enriched 100Mo sample were also performed, and calculated results were compared with the experimental results. Moreover, the thermoseparation of 99mTc from 99Mo was discussed. As a result, it was shown that 99mTc prepared by the thermoseparation using 99Mo produced by the 100Mo(n,2n)99Mo reaction can be a promising substitute for the fission product 99Mo.