NIST researchers Dan Barker, Steve Eckel, Jim Fedchak, Julia Scherschligt and their colleagues developed and tested a new method, known as the cold atom vacuum standard (CAVS), for measuring ultralow pressures.
Credit: NIST
A vacuum chamber is never perfectly empty. A small number of atoms or molecules always remain, and measuring the tiny pressures they exert is critical. For instance, semiconductor manufacturers create microchips in vacuum chambers that must be almost entirely devoid of atomic and molecular contaminants, and so they need to monitor the gas pressure in the chamber to ensure that the contaminant levels are acceptably low.
Now, scientists at the National Institute of Standards and Technology (NIST) have validated a new approach to measuring extremely low gas pressures called CAVS, for cold atom vacuum standard. They have established that their technique can serve as a “primary standard” — in other words, it can make intrinsically accurate measurements without first needing to be calibrated to reference pressure readings.
Having developed CAVS over the last seven years, NIST researchers recently put their technique through its most rigorous tests to date. Their new study, in the journal AVS Quantum Science, shows that CAVS results agreed with the traditional “gold standard” method for measuring low pressures, demonstrating that this new technique can make measurements with the same degree of accuracy and reliability.
Not only can CAVS make measurements as good as those in traditional pressure gauges, but it can also reliably measure the much lower vacuum pressures — a trillionth of the Earth’s sea-level atmospheric pressure and below — that will be required for future chip manufacturing and next-generation science. And its operation, based on well-understood quantum physics principles, means that it can make accurate readings “right out of the box ..
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