Summary:
A UCLA researcher in the Department of Physics has developed a novel method for creating high-bandgap materials doped with thorium-229, enabling the development of advanced nuclear clocks.
Background:
Thorium-229 is the only known isotope with a nuclear transition low enough to be measured using conventional optical techniques. The combination of high stability and subtle sensitivity to environmental conditions enables the development of nuclear clocks and next-generation sensor technologies. Current thorium-229 performance is limited by long cycle times, often requiring several minutes to conduct measurements. Additionally, detecting emitted photons requires complex optical systems and sensitive photon detectors. These limitations highlight the need for thorium-229-doped materials that provide a direct and measurable electrical current, eliminating reliance on complex apparatus and enabling broader applications in next-generation technologies.
Innovation:
Researchers at UCLA have developed a groundbreaking method for doping thorium-229 into a solid-state host material that is opaque to the emitted photons. This unique approach enables, for the first time, direct electrical measurement of the nuclear transition rather than relying on fragile optical detection methods. When the thorium-229 nucleus undergoes rapid decay (~10 microseconds), the energy is efficiently transferred to a nearby electron, generating a measurable electrical current. This process allows clock interrogation times that are eight orders of magnitude faster than the current state of the art, vastly reducing the complexity and cost of precision timing systems.
Unlike traditional nuclear clock designs that require elaborate photon detectors, cryogenics, or complex optical setups, the thorium-229–doped material directly produces an electronic signal that can be integrated into compact devices. This innovation opens the door to miniaturized nuclear clocks with unprecedented stability and robustness, holding transformative potential for applications in precision navigation, secure communications, sensing, and fundamental physics experiments. By combining nuclear-scale stability with chip-scale practicality, this UCLA innovation represents a paradigm shift in the future of timing and metrology.
Potential Applications:
● Timekeeping
○ Telecommunications
○ Data Networks
● Navigation
○ GPS-independent navigation for submarines, spacecraft, remote locations, etc.
● Geodesy/Gravity Sensing
○ Monitor sea levels, detect underground structures, map Earth’s geoid, etc.
● Sensing
○ Electromagnetic
○ Thermal
○ Chemical
○ Quantum
■ Fundamental physics research
● Quantum Devices
Advantages:
● Stability
● Miniaturization
○ Reduced device complexity
● Environmental sensitivity
Development-To-Date:
Initial conception
Related Papers:
[1] Description of the crystal based nuclear clock: Wade G. Rellergert, D. DeMille, R. R. Greco, M. P. Hehlen, J. R. Torgerson, and Eric R. Hudson
Phys. Rev. Lett. 104, 200802 – Published 20 May 2010
[2] Laser Excitation of the 229Th nuclear isomeric transition in a solid-state host
R. Elwell, Chrisian Schneider, Justin Jeet, J.E.S. Terhune, H.W.T. Morgan, A.N. Alexandrova, H.B. Tran Tan, Andrei Derevianko, and Eric R. Hudson
Phys. Rev. Lett. 133, 013201 (2024) – Published 2 July 2024
[3] 229ThF4 thin films for solid-state nuclear clocks
Chuankun Zhang, Lars von der Wense, Jack F. Doyle, Jacob S. Higgins, Tian Ooi1, Hans U. Friebel, Jun Ye, R. Elwell, J. E. S. Terhune, H. W. T. Morgan, A. N. Alexandrova,
H. B. Tran Tan, Andrei Derevianko, and Eric R. Hudson
Nature 636, 603 (2024) – Published 18 December 2024
Reference:
UCLA Case No. 2025-99Y
Lead Inventor:
Eric R. Hudson