THE GAS MONITORING OF THE BESIII DRIFT CHAMBER

Two monitoring proportional counters (MPCs), installed at the inlet and outlet of the gas system of BESIII drift chamber (DC), were used to monitor the operation of the BESIII DC successfully and effectively as reported in this paper. The ratio of G(out)/G(in) (full energy photoelectron peak position of (55)Fe 5.9 keV X-ray in inlet MPC as G(in) and outlet MPC as G(out)) is used as the main monitoring parameter. The MPC method is very useful for the gas detector system.