Expected rate with MU TRIGGER M4 and M5 (bi-gap in OR) Considering all the C side working

1. Contribution to the discussion abut next GC g.martellotti Expected rate with MU TRIGGER M4 and M5 (bi-gap in OR) Considering all the C side working - Rate of cosmics < 1 Hz. - Rate of accidentals in function of R (noise rate/physical channel) : 9.2x10-4(chan M4)x42(chan FOI)x25x10-9(ns)xR2 = 10-2xR2(Hz) R=3 Hz -> TRIG = 0.1 Hz R=10 -> TRIG = 1 R=100 -> TRIG = 100. From the noise rate measurements reported by Rafael, I got the impression that (at nominal low threshold) we could stay at the average level of R <  100 (is it possible to have a better estimate?) This seems to be at the limit of the capability/opportunity of our present DAQ system (ask Callot if this is still true or there is a progress)  I would propose to repeat a high statistics run CALO OR MU With Mu trigger in the “high threshold” condition used in the last GC (the muon tracking results indicate acceptable small inefficiencies) Such run is OK to verify the status of Muon detector with the full side C and to study L0 trigger and Calorimeter (once solved the large misalignment between Muon and Calo)

2. On the other hand it would be very interesting to run and study the detector in HV and threshold conditions approaching the nominal ones(*) . In fact, even if the results obtained in the last CG were at low statistics and still uncertain, they seem to indicate time misalignments relatively small but chamber time response very far from the nominal values (RMS  9 ns ?) We could run one (or more) stations in AND, and overcome the problem of accidentals rate. But this solution would give a poorer time resolution and it would introduce a further element in the game.  So (if Rafael and Davide will manage...) I propose to make a run with high statistics at about nominal threshold with TRIGGER CALO alone. L0Calo triggers on muons with reasonable efficiency (**). Does not introduce time bias, and illuminates also the M4 M5 inner region unlike the L0Mu. (*) The optimal setting of HV must be changed with the present gas mixture? (**) MU TRIGGER: 1 Hz, good triggers 0.45 Hz. Events with reconstructed tracks 49% = 0.22 Hz. TRIGGER CALO:  4 Hz. Events with reconstructed tracks 7.3% (Giacomo) = 0.29 Hz (consistent with different acceptances)