Miniature magnetic resonance spectrometers

For the purpose of in-situ planetary exploration, such as chemical characterization of Martian surface materials by miniature instruments, we have developed miniature Magnetic Resonance Spectrometers (MRS) namely, Nuclear Magnetic Resonance (NMR) and Electron Paramagnetic Resonance (EPR) spectrometers at JPL. They are; Proton-NMR spectrometer for the detection of various forms of water, i.e., free water or adsorbed water in soil or rock pores, or chemically bound water in minerals; Iron-NMR (/sup 57/Fe-MMR) for the characterization of magnetic phase minerals; EPR spectrometer for the detection of oxidant radical species in the soil, oxidation states of paramagnetic ions and chemical characterization of volatiles, e.g., carbonates, sulfates, by detection of color centers in solid or icy matrices. For these spectrometers, resonance is observed by scanning radio (NMR) or microwave (EPR) frequency at a fixed magnetic field provided by a small permanent magnet assembly. Each of the MRS is developed in two configurations; the conventional configuration with samples placed inside the MRS (internal detection mode), and the other by placing the MRS over a sample surface (external detection mode). The external detection mode does not require complex sample handling procedure and it is particularly suitable for selection of samples by a rover for planned Mars sample return missions. The miniature MRS are powered by 9 V batteries, and operated by a lap-top PC.