Researchers at NIST have developed a miniaturized magnetic sensor about the size of a grain of rice that can detect magnetic fields as small as 50 picoteslas. The sensor, which is about 100 times smaller than current atom-based sensors, is based on the principles of NIST’s chip-scale atomic clock. Potential applications include detecting unexploded ordnance, precision navigation, geophysical mapping, and medical instruments.
The sensor works by detecting changes in the energy levels of electrons in the presence of a magnetic field. A tiny sample of rubidium vapor is heated within a sealed cell, and light from a semiconductor laser is transmitted through the atomic vapor. Changes in the amount of laser light absorbed by the atoms indicate the presence of a magnetic field. The key advantages of the new sensor are its accuracy and sensitivity given its small size, compared to other magnetic sensing technologies like fluxgate magnetometers, SQUIDs, and magnetoresistive devices.
Source: https://www.nist.gov/news-events/news/2004/12/chip-scale-magnetic-sensor-draws-mini-clock-design
Keywords: Nuclear, Rubidium, Magnetic, Sensitivity, Metrology
