Among the various nuclides released by the accident at Fukushima Daiichi nuclear power station, nuclides that do not radiate γ-rays are called "difficult-to-analyze nuclides". It is important to identify the origin of these nuclides in the environment. Analysis of these nuclides requires analytical methods with both micro-imaging and isotopic detection. Our mass-imaging instrument has a high lateral resolution and higher ionization selectivity using resonance ionization using two lasers with different wavelengths. Optimization of the wavelength for resonance ionization using a stable Cs compound was performed, and a real environmental particle containing radioactive Cs was analyzed. Isotope images of three kinds of Cs were successfully obtained without interfere from Ba isotopes for the first time. We developed such an imaging technique using a time-of-flight secondary ion mass spectrometry and wavelength tunable Ti:Sapphire lasers for resonance ionization of target elements without mass interference. This is called resonant laser ionization sputtered neutral mass spectrometry.
Miyashita et al. (Fri,) studied this question.