Material thickness measurement using magnetic information

A probe for a system for measuring a material thickness comprising a thickness monitor and a target, the probe comprising:

• an excitation coil for receiving an excitation waveform from the thickness monitor and generating an excitation field therewith;
• a field compensation coil for receiving the excitation waveform from the thickness monitor and generating a cancellation field therewith to cancel the excitation field at a predetermined location;
• and
• a magnetic sensor in the predetermined location for measuring a response magnitude of the target and transmitting a response signal to the thickness monitor.

A method of measuring material thickness utilizing a system comprising a thickness monitor, a probe, and a target, the method comprising the steps of:

• energizing an excitation coil in the probe to excite a response from the target;
• compensating for the effect of the excitation coil on a magnetic sensor of the probe by canceling the field gernerated at the location of the magnetic sensor;
• measuring the magnitude of the response of the target with the magnetic sensor;
• and
• determining the thickness of the material from the measured response.

A system for measuring thickness of a material comprising:

• a thickness monitor for generating an excitation waveform, receiving a response signal, and determining the thickness of the material;
• and
• a probe that is connected to the thickness monitor, the probe comprising an excitation coil, a field compensation coil, and a magnetic sensor,
• wherein the probe receives the excitation waveform with which the excitation coil generates an excitation field and the field compensation coil generates a cancellation field such that the cancellation field cancels the excitation field at the location of the magnetic sensor, the material is excited into exhibiting a response by the excitation field, and the magnitude of the response is measured by the magnetic sensor of the probe which in turn generates the response signal and transmits it to the thickness monitor.

A method of measuring material thickness utilizing a system comprising a thickness monitor and a probe, the method comprising the steps of:

• energizing an excitation coil in the probe to excite a response from the material, wherein the material has properties selected from the group consisting of electrical conductivity and poor electrical conductivity;
• compensating for the effect of the excitation coil on a magnetic sensor of the probe by cancelling the field generated at the location of the magnetic sensor;
• measuring the magnitude of the response of the material with the magnetic sensor;
• and
• determining the thickness of the material from the measured response.