MAGNETIC FIELD MEASUREMENTS ELECTROMAGNET POWER SUPPLY Quantum Electronics Laboratory Faculty of Physics Adam Mickiewicz University in Poznań MAGNETIC FIELD MEASUREMENTS AND ELECTROMAGNET POWER SUPPLY Stanisław Niziński Goal: create project of autonomic system, controlling electromagnet and measuring magnetic field.

MAGNETIC FIELD SENSORS* MAGNETOMETERS B < 1 mT GAUSSMETERS B > 1 mT  Fluxgate  Induction Coil SQUID Magnetoresistive …  Hall Effect  Magnetoresistive  Magnetodiode Magnetotransistor … Hall effect sensor is the most common sensor used to measure high magnetic fields. *Macintyre, Steven A. "Magnetic field measurement."  ENG Net Base (2000). CRC Press LLC. Retrieved 29 March 2014.

Measuring magnetic field Special semicondiuctor Hall Sensors were applied, they have almost constant parameters in 2K - 300K temperature range. There are 5 Hall Sensors located at the measurement unit. It can measure magnetic field in X, Y, Z axes. To measure gradient, we need 2 sensors in one axis, so magnetic field gradient can be measured in X and Y axes only.

Measuring magnetic field external Hall sensor (H0) There is Hall sensor outside the electromagnet, calibrated to determine magnetic field inside the electromagnet during it’s work.

Power supply controller

Power supply controller software interruption every ≈100ms measure magnetic field is field in range? finish procedure YES NO 1. switch on heater 2. switch on power supply measure magnetic field increase current Is field big enough? NO YES 1. switch off heater 2. switch off power supply finish procedure

Measurement setup

Schematic of LabView measuring program

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