A 0.001 Per Cent Hall-Effect Probe

A magnetic-field measurement probe capable of a resolution of 0.001 per cent is described. The probe employs bifilar wound heating pads and a platinum resistance thermometer to maintain the temperature of its enclosure within 0.1°C. A thermistor-resistor network compensates for the effects of self-heating due to changing power dissipation in the control side of the sensitive element. The probe was calibrated and tested with nuclear magnetic resonance equipment. The results obtained are discussed.