Cylindrical proportional chambers of the PIBETA setup

The design and characteristics of two-coordinate multiwire proportional cha mbers are described. The chambers were produced at the Laboratory of Nuclea r Problems, JINR (Dubna), for the PIBETA spectrometer (PSI, Switzerland). C hambers of 120- and 240-mm diameters and 350- and 580-mm lengths, respectiv ely, are made as self-supporting constructions with a small amount of matte r in the radial cross section. Coordinate information is obtained by record ing and processing the signals from the anode wires and strips. The strips are located on the inner and outer cylinders at an angle to the wire. The a ccuracy of determining the Z-coordinate is <200 mu m. The PIBETA spectromet er was installed on the pi(+)-beam at the PSI, and the first session of dat a acquisition was conducted.