Nuclear Spectroscopy: From Natural Radioactivity to Studies of the Most Exotic Isotopes. Department of Physics University of Surrey, Guildford, & Radioactivity Group, Teddington p.regan@surrey.ac.uk
Outline of talk Elements, Isotopes and Isotones Primordial radionuclides…..why so long ? Internal structures, gamma rays and shells. How big is the nuclear chart ? What could this tell us about nucleosynthesis?
286 combinations of protons and neutrons are either stable or have decay half-lives of more than 500 million years. - What are the limits of nuclear existence…i.e. how many different nuclear species can exist?
N/Z ratio changes for stable nuclei from ~1:1 for light nuclei (e.g., 16O, 40Ca) to ~1.5 for 208Pb (126/82 ~ 1.5) - How does nuclear structure change when the N/Z ratio differs from stable nuclear matter?
Accelerator facility at GSI-Darmstadt
A few physics examples….
Evidence for nuclear shell structure….. energy of 1st excited state in even-even nuclei….E(2+).
Summary Radionuclides (e.g. 235U, 238U, 232Th, 40K) are everywhere. Radioactive decays arise from energy conservation and other (quantum) conservation laws. Characteristic gamma ray energies tell us structural info. The limits for proton-richness in nuclei has been reached. Neutron-rich nuclei are harder to make at the extremes, but we are starting to be able to reach r-process radionuclides. - Does the nuclear shell model remain valid for nuclei with ‘diffuse neutron skins’ ?
Dostları ilə paylaş: |