Cluster Reconstruction for the CSR External-target Experiment (CEE) Time Projection Chamber

The Cooler-Storage-Ring External-target Experiment(CEE) is a spectrometer to study the properties of nuclear matter at high baryon density region. The CEE time projection chamber, which uses the state-of-the-art SAMPA electronics read-out chips is the key sub-detector of CEE. Neighboring signals in the same pad row are first grouped together to form a 2-dimensional cluster. Then a hit is created for each cluster at the ADC weighted average signal position. A cluster may also be divided into two or more hits, when the signal ADC vs. time bin has a peak-valley-peak structure, in order to obtain better two-track separation ability. The performance of the algorithm, including 0.100/0.043 cm of hit resolution and 1.1/2.8 cm of double-track resolution in the x/y direction, is also presented.