Performance of 2 mm radius straw tube drift cells

The performance of a 128-channel test module made with straw tubes of 2-mm radius was studied in a test beam and with cosmic rays. Different gases were used, and for each one the time-to-distance relation and the hit efficiency were measured. Comparisons are made between results obtained using two different electronics readouts. The best solution, of 135 mu m, was obtained using 50% ethane, 50% argon and reading out the information with the TDCs (time-to-digital converters), at an operating voltage of 1750 V.<
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