Laser spectroscopy provides model-independent measurements of nuclear ground and isomeric state properties. These include measurements of the nuclear spin, magnetic dipole and electric quadrupole moments and the mean-square charge radii. Such quantities provide a stringent test of shell model calculations, a sensitive probe of single-particle effects and changing collectivity. For high resolution spectroscopy, the collinear beams technique continues to evolve and remains the most prevalent and versatile. This has long been applied at ISOLDE, where high yields of isotopes far from stability are available.
At IGISOL IV, JYFL, thin foil targets and a greater variety of reactions enable enhanced production in some cases. Extraction from the point of production in the target takes place in under a millisecond regardless of the physical and chemical properties.
While necessary technical developments frequently take place, the first laser spectroscopy of nobelium presented several challenges for the field. A move had to be made away from ISOL facilities, to in-flight production at GSI. For the spectroscopy, the atomic structure was not already known. A very different approach therefore had to be taken.