Determination of90Sr in environmental samples with resonance ionization spectroscopy in collinear geometry

1994

A new, fast technique for trace analysis of the radioactive isotopes89Sr and90Sr in environmental samples has been developed. Conventional mass separation is combined with resonance ionization spectroscopy in collinear geometry, which provides high selectivity and sensitivity. In addition, a chemical separation procedure for sample preparation has been developed. The described technique was used to determine the90Sr content in ≈ 870 m3 air samples collected near Munich during and shortly after the Chernobyl reactor accident in April 1986. The content of90Sr was measured to be 1.4 mBq per m3, corresponding to 1.6 × 109 atoms of90Sr per sample. This value is in good agreement with the results…

Fast, low-level detection of strontium-90 and strontium-89 in environmental samples by collinear resonance ionization spectroscopy

1993

Environmental assessment in the wake of a nuclear accident requires the rapid determination of the radiotoxic isotopes 89Sr and 90Sr. Useful measurements must be able to detect 108 atoms in the presence of about 1018 atoms of the stable, naturally occurring isotopes. This paper describes a new approach to this problem using resonance ionization spectroscopy in collinear geometry, combined with classical mass separation. After collection and chemical separation, the strontium from a sample is surface-ionized and the ions are accelerated to an energy of about 30 keV. Initially, a magnetic mass separator provides an isotopic selectivity of about 106. The ions are then neutralized by charge exc…

Trace Analysis of the Radionuclides90Sr and89Sr in Environmental Samples I: Laser Mass Spectrometry

1995

Spurenbestimmung der Radionuclide90Sr und89Sr in Umweltproben I: Laser-Massenspektrometrie

1995

Lifetime measurements of highly excited Rydberg states of strontium I

1993

Lifetimes of Rydberg states of the triplet-series 5s ns3S1 withn = 19–23, 35 and 5s nd3D3 withn = 18–20, 23–28 in the spectrum of neutral strontium have been determined. Observation of the exponential decay after excitation by a pulsed laser in a fast atomic beam and subsequent state-selective field ionization was employed. The lifetimes of the states of the3S1-series show the expectedn*3 dependence on the effective principal quantum number, while the3D3-series is disturbed by configuration mixing. Furthermore, state re-populations induced by black-body radiation have been observed.

Hyperfine structure in 5s 4d 3 D ?5snf transitions of87Sr

1993

The hyperfine spectra of the 5s4d3D1-5s20f, 5s4d3D2-5s23f, and 5s 4d3D3-5s32f transitions of87Sr (I=9/2) have been measured by collinear fast beam laser spectroscopy. The structure in the upper configurations is highly perturbed by fine structure splitting that is of comparable size to the hyperfine interaction energy. These perturbations can be adequately treated with conventional matrix diagonalization methods, using the 5s-electron magnetic dipole interaction terma5s and the unperturbed fine structure splittings as input parameters. Additionally, hyperfine constants for the lower 5s4d3D configurations, including theA- andB-factors and a separation of the individuals- andd-electron contri…

Trace determination of 90Sr and 89Sr in environmental samples by collinear resonance ionization spectroscopy

1995

Collinear resonance ionization spectroscopy has been developed as a sensitive technique for fast trace detection of 90Sr and 89Sr in the environment. A detection limit for 90Sr of 107 atoms in the presence of 1017 atoms in the presence of 1017 atoms of stable Strontium has been achieved, while the applicability of the method has been demonstrated on real world samples. After collection and chemical separation, strontium is surface ionized, accelerated to 33keV and mass separated. The ions are neutralized and the emerging fast atoms interact with an argon ion laser beam (γ=364 nm) in a quasi‐collinear geometry. Optical excitation starts from the long‐lived 5s4d3 D2 state of strontium, which …