A chamber composed of precision Mylar drift tubes

The design of a drift chamber composed of three layers of thin-walled (0.125 mm) precision Mylar tubes is described. Twenty six chambers of this type with areas from 1 × 1 to 2.5 × 2 m2 comprising 4392 drift tubes have been produced for experiments at the 70-GeV accelerator at the Institute for High Energy Physics. The chamber design, the assembling procedure, and test results are presented.