14 DAY TRIAL // A nuclear isomer is a metastable state of an atomic nucleus caused by the excitation of one or more of its protons or neutrons or both. It occupies a higher energy state than the corresponding non-excited nucleus, called the ground state. The nuclear isomer will sooner or later release the extra energy and decay into the ground state.
Radioactive decay is the process in which unstable atoms lose energy by emitting radiation in the form of particles or electromagnetic waves. This decay, or loss of energy, results in an atom of one type, called the parent nuclide transforming into an atom of a different type, called the daughter nuclide. For example: a carbon-14 atom (the "parent") emits radiation and transforms into a nitrogen-14 atom (the "daughter.")
This is a random process on the atomic level, in that it is impossible to predict when a particular atom will decay, but given a large number of similar atoms, the decay rate, on average, is predictable.
Now, Livermore researchers have moved one step closer to being able to turn on and off the decay of a nuclear isomer.
Turning the decay on and off is key to using isomers as high-energy density storage systems such as batteries.
They studied an isomer of Thorium-229, unique in that its excitation energy is near optical energies, implying that one day scientists may be able to transition Th229 nuclei between the ground and isomeric states using a table-top laser.
Firstly, they needed to perform an accurate determination of the isomer's excitation energy above the ground state. In the most recent research, Livermore scientists, along with colleagues from Los Alamos National Laboratory and NASA Goddard Space Flight Center, have made the most accurate measurement of this energy difference using an indirect technique.
The next step will be to use a laser or a synchrotron tuned to the exact energy of the spacing between the two levels and observe the transition from the ground state to the isomeric state.
Once laser excitation has proven possible, helping an excited level decay (and thus give off energy) that can be tackled.
The reason this isomer has been a fascination for scientist for decades is the fact that it could lead to new scientific applications and technology breakthroughs.
Among them are: a quantum many-body study, a clock with unparalleled precision for general relativity tests, a superb qubit (a quantum bit) for quantum computing and the testing of the effects of the chemical environment on nuclear decay rates. Isomers also may serve as a battery for storing large amounts of energy.