In the summer of 2023, the School of Applied and Engineering Physics purchased and installed a BlueFors LD250 cryostat with support from Cornell Engineering’s James R. Meehl Equipment Fund, part of a generous gift from David Meehl ’72, MBA ’74.
A cryostat is an instrument that can maintain samples at incredibly low temperatures. When operating, the temperature inside the cryostat hovers just above 0 degrees Kelvin, which is equivalent to absolute zero, or minus 273 degrees centigrade. It manages to achieve these cold temperatures by cyclic compression and expansion of helium and by using the heat of mixing isotopes of helium—He-3 and He-4—to cool the system to a base temperature of around 10 millikelvin, or .0010 degrees kelvin. Housed in the basement of Clark Hall, the Meehl cryostat became available to users in October 2024, after Rachael Cohn, Ph.D., was hired as cryostat manager in August 2024.
“The facility encourages collaborative projects that enhance the quantum science efforts at Cornell,” said Cohn, who is responsible for all aspects of the cryostat: scheduling, budgeting, and maintaining, as well as assisting users with loading samples or performing measurements. “For example, one of our users is researching how qubits—which are the quantum analog of bits in a classical computer—can lose the information that is encoded in them. Understanding these loss mechanisms can help minimize that loss and make quantum computers more efficient.”
Another researcher currently using the cryostat is investigating current-voltage characteristics of Josephson junctions (two superconductors separated by a thin, non-superconducting barrier) in order to determine key properties, such as critical current, that are essential to optimizing junction fabrication and understanding device performance in quantum circuits. And a third researcher is trying to improve the performance of transmon qubits, a type of superconducting qubit, by improving the quality of the materials used for making devices. Transmon qubits are a promising platform for quantum computing, but their performance is limited by device quality.
Researchers who are interested in learning more or scheduling time on the cryostat can visit the Meehl Cryostat website for more information.