Principle and Software Design of Helmhotz Coil Measurement System

Abstract：

This paper illustrates the measurement principle for constructing Helmhotz coil system by using the magnetic flux method, by which the magnetic parameters of a permanent block can be measured. Also, this paper gives the method of software design based on high precision integrator. If the size of Helmhotz coils is larger enough, the measurement errors coming from the deviations of the block positions can be ignored. With the flux measurement method, the magnetic flux variations between two sample points are not affected by the speed of the step motor, but only related to the space positions of the two sample points. So it reduces the errors coming from the motor vibrations and the speed changes effectively. Using this system, a permanent magnet block used for BEPC mini-β permanent quadrupole has been measured. At last, this paper gives detailed discussions on the system errors arising from the mechanical manufacture deviations and the mechanical installation deviations.