2014 R&D 100 Winner
Superconducting Tunnel Junction (STJ) X-ray SpectrometerX-ray spectroscopy is widely used to determine the elemental and chemical composition of materials. However, Lawrence Livermore National Laboratory and STAR Cryoelectronics LLC’s Superconducting Tunnel Junction (STJ) X-ray Spectrometer offers more than 10 times higher energy resolution than current x-ray spectrometers based on silicon or germanium semiconductors. This higher resolution is made possible through the use of a superconducting sensor that excites 1,000 times more free charges than is possible in a semiconductor-based sensor. This allows for the clear separation of characteristic x-ray lines, even at low energies and in complicated multi-element samples. The team’s development of an automated liquid-cryogen-free cryostat allows for operation of the instrument at the required temperature of 0.3 K, and they solved acquisition time limitations by using up to 112 sensors on a single array. The improved precision of the STJ x-ray spectrometer over current technology, along with its ease of operation, will make high-accuracy x-ray fingerprinting available to non-expert users, including computer chip manufacturers, medical companies and forensics specialists.

X-ray spectrometer

Lawrence Livermore National Laboratory
STAR Cryoelectronics

Development Team

The Superconducting Tunnel Junction (STJ) X-ray Spectrometer Development Team
Robin Cantor, Principal Developer, STAR Cryoelectronics LLC
Stephan Friedrich, Principal Developer, Lawrence Livermore National Laboratory
Jan D. Batteux, Lawrence Livermore National Laboratory
Eddie J. Bencomo, STAR Cryoelectronics LLC
Matthew H. Carpenter, STAR Cryoelectronics LLC
Owen B. Drury, Lawrence Livermore National Laboratory
John A. Hall, STAR Cryoelectronics LLC
Simon E. Labov, Lawrence Livermore National Laboratory