Backscatter apparatus and method for measuring thickness of a continuously moving coated strip of substrate material

A backscatter thickness measuring apparatus for measuring the thickness of a coating on a strip of substrate material moving at a predetermined speed from a feed supply to a take-up location comprising:

• probe means for irradiating a portion of the coating on the strip of substrate material and detecting the backscatter radiation from such portion during a measurement period;
• counting and measurement means connected to the probe means for counting the backscatter radiation during the measurement period and determining the thickness of the coating of such portion in accordance with the backscatter count;
• means for positioning the probe means at a first position whereby the probe means is held adjacent the strip prior to the measurement period;
• means for stripping the probe means away from the moving strip of substrate material after the measurement period and returning the probe means to the first position prior to the commencement of a new measurement period.

A method utilizing backscatter apparatus for measuring the thickness of a coating on a strip of substrate material moving at a predetermined speed from a feed supply to a take-up location comprising:

• irradiating a portion of the coating on the strip of substrate material with a backscatter probe and detecting the backscatter radiation from such portion during a measurement period;
• moving the backscatter probe in adjacent stationary relation with such portion of the coating on the strip of substrate material during the measurement period;
• counting the backscatter radiation during the measurement period;
• and
• determining the thickness of the coating of such portion in accordance with the backscatter count.

A method of utilizing backscatter apparatus for measuring the thickness of a coating on a strip of substrate material moving at a predetermined speed from a feed supply to a take-up location comprising:

• irradiating a portion of the coating on the strip of substrate material with a backscatter probe and detecting the backscatter radiation from such portion during a measurement period;
• positioning the backscatter probe at a first position whereby the backscatter probe is held adjacent the strip prior to the measurement period;
• moving the backscatter probe in adjacent stationary relation with the strip of substrate material during the measurement period;
• counting the backscatter radiation during the measurement period;
• determining the thickness of the coating of such portion in accordance with the backscatter count;
• stripping the backscatter probe from the moving strip of substrate material after the measurement period;
• returning the backscatter probe to the first position prior to the commencement of a new measurement period.