|Cesium atomic clock on a chip.
Sadly I don't actually have this device, it was only loaned to me for a day to photograph it. Normally cesium clocks are large things, like a breadbox, washing machine, or small car, depending on the model. This thing is in inch across, and most of that is just the mounting board, the clock itself is less than a quarter of an inch high and a sixteenth inch wide. In that minuscule space are contained a pair of radio antennas, a heating coil, and a glass ampule with cesium trapped inside.
This particular example is a demonstration model where the various parts are not wired up to the contacts on the supporting circuit board. This allows you to see the tower of components clearly
Thanks to James Burrus of NIST for arranging the loan of this fabulous device.
Acquired: 24 March, 2009
Text Updated: 24 March, 2009