Development of Cylindrical Drift Chamber for COMET Phase-I

In the experiment, CDC Prototype II and III were stringed with φ 25µm and φ 30µm tungsten anode wire coated with gold, respectively. Three He-based gas candidates with iC4H10, CH4 and C2H6 were studied. For the setup, two scintillators were used as the trigger and four tracking chambers were used to reconstruct electron beam tracks in 3 dimension. The data was acquired by using four Belle II RECBE boards. With different setting of applied high voltage and signal threshold, the detector response with efficiency more than 95% and spatial resolution less than σ =200 µm for each prototype chamber were confirmed. The result of this experiment has lead us to finalize the parameters of the CDC in Phase-I. In this paper, the analysis method and result will be described in details.