Nuclear Spectroscopy: From Natural Radioactivity to Studies of Exotic Isotopes. Prof. Paddy Regan

Nuclear Spectroscopy: From Natural Radioactivity to Studies of Exotic Isotopes.

• Prof. Paddy Regan

• Chair of Radionuclide Metrology,

• Department of Physics

• University of Surrey, Guildford,

• &

• Radioactivity Group,

• National Physical Laboratory,

• Teddington

• [e-mail]

Outline of talk

• Elements, Isotopes and Isotones

• Alpha, beta and gamma decay

• Primordial radionuclides…..why so long ?

• Internal structures, gamma rays and shells.

• How big is the nuclear chart ?

• What could this tell us about nucleosynthesis?

Nuclei can also decay by  emission.. ejection of a 4He nucleus…. Depends (again) on binding energies & masses

Radioactive decays occur as a result of

• Radioactive decays occur as a result of

• conservation of mass/energy E=mc2

How do you measure the gammas? i.e., How do you see inside the nucleus?

Making a Radiological Map of Qatar

• Arabic Gulf state,

• Oil Rich (oil industry all around)

• To host World Cup (2022)

Characteristic gamma signatures can be used

• Characteristic gamma signatures can be used

• to measure emissions of radionuclides from

• ‘man-made sources’ such as Fukushima,

• Chernobyl, nuclear weapons tests…etc.

• Nuclear Fission fragments:
• 137Cs (T1/2 = 30 years)
• 131I (T1/2 = 8 days)
• Neutron-capture on fission products in reactors
• 134Cs (T1/2 = 2 years)

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.