High-accuracy teslameter with thin high-resolution three-axis Hall probe

• Published in: Measurement : journal of the International Measurement Confederation Vol. 98; pp. 407 - 413
• Main Authors: Popovic Renella, Dragana, Dimitrijevic, Sasa, Spasic, Sasa, Popovic, Radivoje S.
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.02.2017; Elsevier Science Ltd
• Subjects: Analog computers; Analog to digital conversion; Analog to digital converters; Calibration; Digital computers; Electronics; Gaussmeter; Hall effect; Hall probes; Linearity; Magnetic fields; Magnetic measurement; Measuring instruments; Sensors; Spatial resolution; Temperature sensors; Teslameter; Thin Hall probe; Three axis; Three-axis Hall probe; Touch screens; Three-axis Hall probe; Gaussmeter; Thin Hall probe; Teslameter; Magnetic measurement
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/j.measurement.2015.06.023

•The digital teslameter incorporates a 3-axis Hall probe that is only 250μm thick.•Single silicon chip with integrated horizontal and vertical Hall devices.•Measuring magnetic field vectors with the spatial resolution of 100μm.•Magnetic resolution of ±2ppm of the range; accuracy of 0.001% of the range.•Temperature coefficient is less than 5ppm/°C; and angular errors are less than 0.1°. The new digital teslameter system (also called Gaussmeter) incorporates a 3-axis Hall probe, analog electronics based on the spinning-current technique, 24-bit analog-to-digital converter, computer, and 7-digit touch-screen display. The Hall probe is a single silicon chip with monolithically integrated horizontal and vertical Hall magnetic sensors and a temperature sensor. The Hall sensor chip is encapsulated in a robust ceramic package, a version of which is only 250μm thick. The spinning-current eliminates most of the Hall probe offset, low-frequency noise, and the planar Hall voltage. The errors due to the Hall element non-linearity and the variations in the probe electronics temperatures are eliminated by a calibration procedure based on a three-variable second-order polynomial. The errors due to the angular errors of the Hall probe are eliminated by a calibration of the sensitivity tensor of the probe. These new developments resulted in a teslameter that can measure magnetic field vectors from about 1μT to 30T, with the spatial resolution 100μm, magnetic resolution ±2ppm of the range, the accuracy ±0.0001% of reading +0.001% of range, temperature coefficient less than 5ppm/°C, and angular errors less than 0.1deg.