Detection of single atoms by resonance ionization spectroscopy

• Published in: Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 1987
• Subjects: Ice cap
• Online Access: http://dx.doi.org/10.1098/rsta.1987.0079; https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1987.0079

Rutherford’s idea for counting individual atoms can, in principle, be implemented for nearly any type of atom, whether stable or radioactive, by using methods of resonance ionization. With the technique of resonance ionization spectroscopy (ris), a laser is tuned to a wavelength that will promote a valence electron in a Z-selected atom to an excited level. Additional resonance or non-resonance photoabsorption steps are used to achieve nearly 100% ionization efficiencies. Hence, the ris process can be saturated for the Z-selected atoms: and because detectors are available for counting either single electrons or positive ions, one-atom detection is possible. Some examples of one-atom detection are given, including that of the noble gases, to show complementarity with accelerator mass spectrometry ams methods. For instance, the detection of 81 Kr by using ris has interesting applications for solar-neutrino research, ice-cap dating, and groundwater dating.