From noise to signal - a new approach to LHCb muon optimization

One has to exploit the LHCb muon detector at the lowest possible gas gain and operational voltage in order to minimize the charge accumulated during 10 years of the LHCb experiment keeping the aging effects as low as possible. The detector lifetime prolongation 1.5-2 times can be achieved following the optimization of the LHCb muon system proposed in this note. An optimization of the LHCb muon system assumes: minimization of the electronics thresholds and detector gas gain, a choice of the working point near the knee of the efficiency plateau at high enough efficiency at stabilization the signal-to-noise ratio during long-term data taking runs by gas gain stabilization. An efficiency of each chamber tuned once by a time alignment remains constant at the constant gas gain. Cluster size, cross-talks, multi-hits become constant and minimal at constant and minimal gas gain. It is shown in the note how to reconstruct the noise distribution in each chamber already installed in the pit and to measure precisely offset and the Equivalent Noise Charge ($ENC$) both of which specify the minimal electronics threshold. $ENC$ enlargement problem related to threshold increasing at high particle rates is discussed. $ENC$ monitoring for each physical channel of the system during the LHCb experiment is proposed in order to detect aging of the LHCb muon system at the earliest stage and make correction.