Straw chamber prototype for COMPASS tracker system

The construction principals for straw tube chambers with size 3 x 2 m2 for Large Area Tracker (LAT) of COMPASS experiment are presented. A prototype with 2 m straw tubes has been made assembled. See possibility mechanical deformation and his dimension. Laboratory tests of the prototype were performed. A good mechanical tolerance and stability of gas gain in longitudinal 2 m straw tubes was demonstrated. Also studying dependence of the tube lengthen with change of humidity and temperature. Bring results test of chamber prototype with size 600 x 800 mm make in CERN. (author)