Scanner for automated high precision measurements of wire positions in wire chambers

We have developed a device to perform precise automated measurements of the relative wire separations in a planar wire chamber. The measurement scheme involves slowly passing the wire chamber through a laser beam directed onto a photodiode. The measured position of the chamber as a function of time is then correlated with the photodiode response to yield the relative wire positions with a mean accuracy of better than 10 μm (FWHM). The operational principles, system components, and results from our studies are discussed.