A full-size multi-wire drift chamber prototype for the CSR external-target experiment

This study reports on the design, simulation, construction, and testing of a full-size prototype of the multi-wire drift chamber for the CSR external-target experiment. The multi-wire drift chamber array incorporates drift cells of three different sizes: 8 × × 8 mm ² 2 , 10 × × 10 mm ² 2 , and 15 × × 15 mm ² 2 . Simulation studies were carried out to compare their electron drift time spectra, R-T relations, and position resolution. The prototype was constructed based on the design of the multi-wire drift chamber closest to the target. Since the beam passes through the center region of the multi-wire drift chamber, the prototype features a special beam avoidance design. The design ensures that the detector is sensitive to reaction products while remaining unresponsive to heavy ion beams. The size of the prototype is 930 × × 1660 mm ² 2 , comprising 960 drift cells. Testing was conducted with dedicated electronics. An energy resolution of 22% was achieved for the ⁵⁵ 55 Fe source; the track residuals were approximately 300 μ m for the cosmic rays; the detection efficiency of each layer exceeds 96% for the cosmic rays.