Optimization of the conditions for simultaneous non-selective excitation of plutonium isotopes for isotope ratio measurements in resonance ionization mass spectrometry

Broadband non‐selective excitation of plutonium isotopes for isotope ratio measurements in resonance ionization mass spectrometry: a theoretical study

“…This is because of the dominating power broadening in each excitation step and also the large bandwidth of the excitation lasers. As reported earlier, the isotopes of plutonium nearly fall along the diagonal two‐photon ridge . The excitation efficiency along the diagonal two‐photon line is nearly invariant up to the resonance frequency position of the 238 Pu isotope (Table ) which is a clear indication of the indiscriminate excitation of all the isotopes under these excitation conditions when the lasers are tuned to the resonance of the 240 Pu isotope …”

“…Under these optimized conditions of the powers of the excitation lasers and bandwidths indiscriminate excitation could be achieved with minimal isotope bias. As discussed in the earlier study the optimized conditions for achieving high excitation efficiency of the resonant isotope do not guarantee that the yield of the off‐resonant isotope is also comparable, leading to a significant bias in the excitation of the off‐resonant isotope . With increase in the laser powers, the off‐resonant isotope also falls into the power‐broadened width of the transition; thereby comparable excitation efficiencies are feasible for both the resonant and the off‐resonant isotopes.…”

“…Therefore, it can be inferred that, for the first step even if the laser is tuned to the resonance of 240 Pu isotope, powers about seven times or greater than the saturation power of the first laser can cause appreciable ionization of the off‐resonant 238 Pu isotope. Hence, it has been concluded that low powers and smaller bandwidths are insufficient for non‐selective excitation and they need to be further increased …”

“…The present study was motivated by the need to arrive at conditions for the indiscriminate excitation/ionization of all the plutonium isotopes leading to very little isotope bias between the resonant and off resonant isotope. In the present work, the isotope bias between the resonant and the off‐resonant isotope has been further reduced compared with our previous work for the indiscriminate excitation of plutonium isotopes . Density matrix formalism has been used to investigate theoretically the excitation of plutonium isotopes via a three‐color resonant excitation scheme for the indiscriminate excitation of plutonium isotopes.…”

Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples

“…Mass spectrometric techniques such as TIMS [275], AMS [276][277], RIMS [97,278], and ICP-MS [64,[279][280][282][283] have also been used for the determination of Pu isotopes. During the last decade, the use of ICP-MS has gained a increased interest as an alternative to alpha spectrometry because of the good sensitivity, short analytical time and 239 Pu -240 Pu - 242 Pu isotopic information which are difficult to obtain through alpha spectrometry due either to overlapping peaks of 239 Pu at low levels (fg-pg range).…”