A quantitative and comparative study of radionuclidic and chemical impurities in water samples irradiated in a niobium target with Havar vs. niobium-sputtered Havar as entrance foils.
Enriched and natural abundance water samples were irradiated in a niobium (Nb) chamber target with Havar and Nb-sputtered Havar foils. Irradiations were performed with 17.5MeV protons at currents from 35 to 100microA lasting for 1-2.5h. Radionuclidic and chemical (cationic) impurities were determined via gamma spectroscopy and ICP-MS, respectively. Anionic impurities were evaluated by ion chromatography. Impurities in water samples irradiated with the Havar-Nb foils were much lower than the samples irradiated with an unmodified Havar foil. No significant differences were observed in the impurity levels between samples of H(2)(18)O-enriched and natural abundance water. Radionuclidic impurities were observed to decrease after 3-4 irradiations on a fresh Havar entrance foil, and reached a constant value for subsequent irradiations with the same integrated current. For targets covered with Havar foil, radionuclidic impurities were found to be proportional to the beam-integrated current regardless of the beam power and, unexpectedly, dependant of the beam power when using a Havar-Nb foil.
Edmonton PET Centre, Cross Cancer Institute, Alberta Cancer Board, Edmonton, AB, Canada. Miguel.Avila-Rodriguez@utu.fi
Miguel A
MA
Avila-Rodriguez
John S
JS
Wilson
Steve A
SA
McQuarrie
D000497:Alloys / Q000737:chemistry*; D005462:Fluorine Radioisotopes / Q000737:chemistry* / Q000528:radiation effects; D009556:Niobium / Q000528:radiation effects*; D011868:Radioisotopes / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000528:radiation effects*
D000497:Alloys; D005462:Fluorine Radioisotopes; D011868:Radioisotopes; D014874:Water Pollutants, Chemical; D009556:Niobium; D014867:Water