Christoph E. Düllmann (Mainz): No RIS(i)K(o) – No Fun

Optical spectroscopy of transuranics gives access to atomic and nuclear properties. Efficient isotope production schemes involving the two highest-neutron flux reactors on the American and the European continents - HFIR at Oak Ridge and the ILL reactor Grenoble - paired with nuclear chemical competences and high total efficiencies for actinide spectroscopy available in Mainz allowed pushing the limit to the heaviest macroscopically available isotopes, the ₉₈Cf - ₉₉Es - ₁₀₀Fm region. Complementary work using accelerator-produced isotopes up to ₁₀₂No performed at GSI Darmstadt has even allowed spearheading optical spectroscopy into the atom-at-a time realm. I will discuss the production, isolation, and characterization of such samples (containing as few as 10⁷ atoms), and how hyperfine, isotope shift, and Rydberg spectroscopy -performed at the RISIKO laser mass spectrometer in Mainz - allowed determining nuclear moments, nuclear charge radii, and ionization potentials. Using RISIKO as a laser mass separator supported obtaining the most stringent upper limit of the electron neutrino mass in the ECHo project led by Heidelberg University. Excursions to the superheavy elements that are in the focus of a broad research program at GSI Darmstadt, and to neutron star mergers that might or might not produce superheavies in Nature, will highlight links to other, related fields.