Magnetic field sensors (IMAGE) University of Colorado at Boulder Caption Artist's depiction of a new strategy for measuring the direction of magnetic fields by exposing a cell containing roughly a hundred billion rubidium atoms to a microwave signal. Credit Steven Burrows/JILA Usage Restrictions Use with credit only License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.