proton magnetometer

instrument which measures very small variations in the Earth's magnetic field

en-GB/ˈpɹəʊtɒn ˌmæɡnɪˈtɒmɪtə/
en-US/ˈpɹoʊˌtɑn ˌmæɡnɪˈtɑmɪtɚ/

الفئات:

magnetometer