Search

Two ICP-MS methods were developed to measure the radiotoxic isotope 226Ra in brain tissues from a radium dial painter worker. The first method was a direct analysis of acid digested samples using quadrupole ICP-MS. The instrumental LOD of 226Ra was 0.1 ng kg−1. Polyatomic interferences at m/z 226 were investigated and Pb was identified from a polyatomic interferent in an in-house sample prepared from bovine brain, with a 226/208 formation ratio of 4 × 10−8. The quadrupole ICP-MS method was also used to measure levels of beryllium, strontium, and uranium. A second method was developed that included cation-exchange chromatography to separate 226Ra followed by analysis with sector field MC-ICP-MS. The instrumental LOD for the cation exchange method with MC-ICP-MS detection was 0.5 pg kg−1 (19 mBq kg−1). The measured concentrations of 226Ra in different brain regions ranged from 0.09–0.72 ng kg−1 (3.3–27 Bq kg−1) and radium was non-uniformly distributed in the brain. [ABSTRACT FROM AUTHOR]

In January 2006 the beryllium reflector and graphite wedge that contained the k0 INAA irradiation position were replaced at the University of Missouri Research Reactor. Prior to replacement the average values of the flux ratio, f, and the epithermal non-ideality factor, α, were 57.4 ± 4.5 and 0.039 ± 0.012. The values of f and α immediately after the beryllium and graphite wedge replacement were 39.4 ± 0.6 and 0.021 ± 0.002. Subsequent measurements indicate that the neutron spectrum hardened with time, possibly due to the buildup of the 6Li atom density to saturation. [ABSTRACT FROM AUTHOR]