Microgradient Cesium Magnetometer Development.
Abstract
A series of preliminary tests have been performed with the laboratory demonstration model of the optically-pumped cesium microgradient magnetometer. Additional tests were conducted in earth's magnetic field at an outdoors site which was isolated from large scale magnetic disturbances. The smallest change in differential magnetic field between the two sensors was 19 nanogauss. Since the separation of the sensors is 1.5 feet, the threshold gradient is 13 nanogauss/foot. This threshold was most likely determined by the electronic test equipment which was between 12 and 15 feet from the sensor. The magnetic field gradients from this equipment also limited the transverse relaxation time of the cesium resonance to about 5 msec. The signal-to-noise ratio at the outputs of the self oscillating cesium magnetic resonance circuits was 85 dB. The theoretical sensitivity for these values of signal-to-noise and relaxation time is 5 nanogauss which at the 1.5 foot spacing corresponds to a gradient of 3.3 nanogauss/foot. Test operation in an improved magnetic environment with the test equipment further from the sensor should demonstrate a threshold approaching the goal of 1 nanogauss/foot.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1974
- Accession Number
- ADA006596
Entities
People
- Donald S. Bayley
- James H. Simpson
- Lincoln Ferriss