A field-cancelling device was designed to protect the Scanning Electron Microscope (SEM) in room B18 of McNutt Hall from magnetic field interference. At high resolution, the magnified images were being distorted by 60 Hz magnetic fields in the room. The field-cancelling device is designed to operate over a range of 0 to 1 kHz and solve most of this problem.

The device has a set of X, Y & Z axis pick-up coils to detect magnetic fields. There are coils in matching X, Y & Z axes installed in the room around the SEM. The device takes the input of the pick-up coils and sends out an equal and opposite field through the coils around the room in order to cancel the interference. There is an indicator LED on the front panel of the device to show that it is working properly. The indicator will turn off if the magnetic interference is stronger than the box is able to cancel.

Magnetic Field Cancellation System for use with an Electron Microscope

Peter Sayers, Tonica Iglehart and Louise Kendrick

Peter, Louise and Tonica standing next to (and beneath) their magnetic field cancelling system