Author/Authors :
Liu، نويسنده , , J.B. and Qin، نويسنده , , Z.H. and Wu، نويسنده , , L.H. and CHEN، نويسنده , , C. and Zhuang، نويسنده , , B.A. and Chen، نويسنده , , Y.B. and Jin، نويسنده , , Y. and Liu، نويسنده , , R.G. and Ma، نويسنده , , X.Y. and Ma، نويسنده , , Loretta Y.Y. and Tang، نويسنده , , X. and Wang، نويسنده , , L. and Xu، نويسنده , , M.H. and Zhang، نويسنده , , G.F. and Zhu، نويسنده , , M.X. and Zhu، نويسنده , , Q.M.، نويسنده ,
Abstract :
A prototype of the BESIII drift chamber was tested with He / C 3 H 8 ( 60 / 40 ) gas mixture in a 1T magnetic field at the π -2 beam line of KEK 12 GeV PS. The drift distance–time relationship was extracted for various conditions. The performance of the chamber, such as the spatial resolution, the d E / d x resolution and the cell efficiency, was studied in detail. The d E / d x was measured as a function of β γ to calculate the particle separation power. Based on the test results, the operating voltage of the BESIII drift chamber is optimized to be 2200 V, resulting in a spatial resolution better than 110 μ m , a cell efficiency over 98%, a d E / d x resolution better than 5% and the 3 σ π / K separation at a momentum exceeding 700 MeV / c . These results confirm the validation of the physics design of the BESIII drift chamber.
Keywords :
BESIII , Drift chamber , Beam test , RESOLUTION
