Laser resonant photoionization detection of traces of the radioactive isotope 221Fr in a sample
Andreev S. V., Letokhov V. S., Mishin V. I.
The hyperfine splitting oftheZ)2 line of the isotope22'Fr (TU2 = 4.8 min) has been measured. The ionization potential of the francium atom has been refined: Ej <4.154 eV. The experiments were carried out at a francium flux of 8 χ 102 isotopes/s from the sample. The sensitivity of the detection of Fr in a sample is 104 atoms.