Progress of ultra trace determination of technetium using laser resonance ionization mass spectrometry.

Laser resonance ionization mass spectrometry (RIMS) represents one of the most sensitive and selective techniques for ultra trace determination of long-lived radioisotopes. The isotope (99g)Tc constitutes a specific candidate of high relevance concerning its environmental behavior as well as fundamental research applications. Based on the recent precision determination of the ionization potential of technetium by laser resonance ionization, refined resonant optical excitation pathways have been derived for analytical determination of ultra trace amounts of (99g)Tc by laser mass spectrometric approaches. The state of the art and the specifications of RIMS-based ultra trace determination for (99g)Tc, leading to a level of detection of ε ≈ 3 × 10(-4) atoms (3 µBq), are reported.

Time profile of ion pulses produced in a hot-cavity laser ion source.

The time spreads of Mn ions produced by three-photon resonant ionization in a hot-cavity laser ion source are measured. A one-dimensional ion-transport model is developed to simulate the observed ion time structures. Assuming ions are generated with a Maxwellian velocity distribution and are guided by an axial electric field, the predictions of the model agree reasonably well with the experimental data and suggest that the ions are radially confined in the ion source and a substantial fraction of the ions in the transport tube are extracted.

Emittance characterization of a hot-cavity laser ion source at Holifield Radioactive Ion Beam Facility.

The first investigation of the transverse emittance of a hot-cavity laser ion source based on all-solid-state Ti:sapphire lasers is presented. The emittances of (63)Cu ion beams generated by three-photon resonant ionization are measured and compared with that of the (69)Ga and (39)K ion beams resulting from surface ionization in the same ion source. A self-consistent unbiased elliptical exclusion method is adapted for noise reduction and emittance analysis. Typical values of the rms and 90% fractional emittances of the Cu ion beams at 20 keV energy are found to be about 2 and 8 pi mm mrad, respectively, for the ion currents of 2-40 nA investigated. The emittances of the laser-produced Cu ion beams are smaller than those of the surface-ionized Ga and K ion beams.