Novel high-performance helium free precession (HFP) magnetometer is proposed for use in geomagnetic field measurements and magnetic geophysical exploration. We propose in Phase I to define a concept for a portable laser-pumped helium 3 magnetometer which has small size, high sensitivity and low power consumption. The key technical component is a miniature tunable near-infrared laser pump source developed by Polatomic for NASA use in a helium 4 space magnetometer. The laser pumping light and sensor read-out will be carried by optical fiber link between the sensor and the laser/electronics package. During Phase I we will assess the feasibility of the laser-pumped helium 3 magnetometer and optimize the laser pump source for pumping helium 3. The concept will be validated in Phase II with the design, fabrication and testing of a laser-pumped helium 3 magnetometer. In Phase II two sensors will be built in order to evaluate a laser-pumped helium 3 gradiometer. If technically feasible, the laser pumped helium free precession magnetometer would replace the proton free precession (PFP) magnetometer as the world standard. The HFP would provide continuous read-out and have sensitivity improved by more than an order of magnitude over the PFP.
