Investigations on atomic and oxide ion formation of plutonium and uranium in thermal ionization mass spectrometry (TIMS) for determination of 238Pu

A novel approach for the determination of 238Pu by thermal ionization mass spectrometry (TIMS) using interfering element correction methodology

“…Based on the experiments carried out for studying the ion source chemistry of U and Pu, using synthetic mixtures of U and Pu, it was observed that Pu/U amount ratio of about 5 is optimum [9]. This amount ratio does not affect the yield of Pu + ions and at the same time, one gets sufficient signal intensity of both the isotopes of U using UO + ion.…”

“…This IEC methodology can only be used if the evaporation and ionization characteristics of the two elements are distinctly different. Previously, we have studied the ion source chemistry of U and Pu using synthetic mixtures with Pu/U amount ratios of 2, 5 and 10 using a double filament assembly in TIMS, with an objective to optimize the filament heating conditions for the production of UO + and Pu + ions at two different sets of filament heating conditions [9]. These studies prompted us to investigate the possibility of first determining 238 U/ 235 U atom ratio in the sample by monitoring the intensities of ions at m/z 254 and 251, corresponding to 238 UO + and 235 UO + , respectively, at filament temperatures where PuO + is not formed.…”

A novel method for trace uranium determination in plutonium by thermal ionisation mass spectrometry

“…The mixture solutions were evaporated to near dryness and 2 L solution from this mixture was loaded on to the high purity rhenium filament in a double filament assembly [2]. The ionisation and vaporization filaments were heated to about 6 A and 2-2.4 A, respectively, to obtain sufficient UO + ion current without forming PuO + [2].…”

“…Previous studies [1][2][3] from our laboratory demonstrate the formation of atomic and molecular ions (M + and MO + ) using synthetic mixtures of U and Pu in different ratios. These studies [2] showed that it was possible to produce UO + ions in the absence of PuO + by using a multiple filament assembly heated under specific conditions.…”

“…These studies [2] showed that it was possible to produce UO + ions in the absence of PuO + by using a multiple filament assembly heated under specific conditions. These studies prompted us to further investigate the possibility of determining trace levels of U using * Corresponding author.…”