High efficiency laser resonance ionization of plutonium

Abstract

Three-step resonance photoionization spectra of plutonium have been studied with Ti:Sapphire lasers for the development of efficient laser ionization schemes for ultra-trace analysis of Pu isotopes by resonance ionization mass spectrometry. We observed eighteen intermediate excited states of even parity in the energy range 35568–36701 $${\text {cm}}^{-1}$$ cm - 1 , thirteen of them have not been previously documented, and a larger number of high-lying excited states and autoionizing states of odd-parity between 48238 and 49510 $${\text {cm}}^{-1}$$ cm - 1 . Three-color, three-photon ionization schemes via six intermediate states were evaluated under similar ion source operating conditions. This led to a highly efficient three-step scheme with an overall ionization efficiency of $$51.1 \pm 1.3\%$$ 51.1 ± 1.3 % , which is an order of magnitude improvement over the previously reported ionization efficiency for Pu.

Transuranium isotopes at ISAC/TRIUMF

“…Each option can provide a significant enhancement of ionization efficiency compared to surface ionization, though resonant ionization steps usually require lower laser intensities to saturate the transition with regard to non-resonant ionization. Plutonium has been an element of interest for RIS as soon as the concept was developed [10] and has been a topic of research ever since [11]. A variety of excitation schemes for different laser systems have been investigated yet many remained unpublished due to nuclear non-proliferation concerns.…”

New Developments in the Production and Research of Actinide Elements

“…Some trace analysis techniques rely on laser resonance ionization or light absorption and therefore also require a thorough knowledge of atomic structure. For resonance ionization spectroscopy (RIS) of actinides, the development of efficient excitation and ionization schemes is ongoing [97][98][99][100], and recent reports attest to advances in the use of spatially resolved secondary neutral mass spectrometry combined with RIS on sample atoms [96,101,102].…”

Ridge regression energy levels calculation of neutral ytterbium (Z = 70)

“…In recent years, with the development of photoionization detection technology, substantial progress has been made in the spectral analysis of complex atomic systems. [4][5][6][7][8][9][10][11] However, from the National Institute of Standards and Technology (NIST) Atomic Spectra Database, there is no systematic experimental data for high-Z elements, especially lanthanides and actinides. [12] On the one hand, the high cost of sample preparation and high radioactivity bring much inconvenience in the experimental measurement.…”