Measurement device for minimizing external magnetic disturbance

摘要

Provided is a ΔE measuring device minimizing external magnetic disturbance, more particularly, a ΔE measuring device measuring a change (ΔE) in elastic modulus under a magnetic field by removing a bias effect by the earth's magnetic field and a magnetic tool and device and using a magneto acoustic resonance method. With the ΔE measuring device, a space minimizing external magnetic disturbance using three-axis Helmholtz coils is provided and the ΔE measuring device having a plurality of coil structures is inserted into the space, thereby making it possible to minimize external magnetic field disturbance.

主权项

1. A change in elastic modulus (ΔE) measuring device minimizing external magnetic disturbance, comprising:
three-axis Helmholtz coils arranged in x, y, and z axis directions to remove the earth's magnetic field; a three-axis magnetic sensor installed at the center of the three-axis Helmholtz coils to measure magnetic fields formed in the three-axis Helmholtz coils; a second power supply unit supplying offset current offsetting the measured magnetic fields to the three-axis Helmholtz coils according to the measured magnetic fields; a variable direct current (DC) magnetic field applying coil inserted into and seated in the three-axis Helmholtz coils; a frequency variable alternate current (AC) magnetic field applying coil inserted into and seated in the variable DC magnetic field applying coil; a magneto acoustic resonance signal detecting coil inserted into and seated in the frequency variable AC magnetic field applying coil and having a sample inserted thereinto and seated therein, the sample corresponding to an object to be measured; a signal generator applying an AC current signal to the frequency variable AC magnetic field applying coil; a first power supply unit applying a DC current signal to the variable DC magnetic field applying coil; a signal measuring unit measuring a magneto acoustic resonance frequency detected in the magneto acoustic resonance signal detecting coil; and a calculating unit calculating an elastic modulus using the magneto acoustic resonance frequency and commanding the second power supply unit to supply the offset current.