Precise and accurate uranium isotope analysis by modified total evaporation using 1013 ohm current amplifiers

This study presents analytical advances in thermal ionization mass spectrometry for uranium isotope analysis involving minor isotopes. The potential of 10(13) ohm current amplifiers for detecting minor isotope ion beams down to the 10 kcps range during modified total evaporation analyses is assessed on sub-microgram U loads, which is one order of magnitude less material than typical. Sub-aEuro degrees to aEuro degrees precision and accuracy may be achieved for uranium isotopic ratios in the 10(-5) to 10(-4) range. This is 1.2-2.9 times better than expected from scaling down the performance achieved on microgram loads using 10(12) ohm current amplifiers.