Calorimeter calibration -Initial calibration -Gain following -Archiving

Annealing from LED Only 30% of LED operational (readout?) Feb/MayFeb/Nov Annealing effect went on all the year 2-4% May->November

Effect /crate Feb8->13 Take LED with new system as soon as possible – will help to fix the initial calibration. Feb15-11 Feb12-8

Inner part Crate 16 Increased dispersion

Inital 2015 calibration Do the photoelectron test done for the initial calibration still possible ? To follow the evolution : even with partial LED system ( if stable) we should take LED events The annealing from fiber important and still goes on (4% May-November) The annealing from PMT (scintillators) smoother(2%)

To apply the occupancy method 80Hz minimum biais event needed Stable mu Calculate the occupancy rate ( see Irina Machkhilyan LHCb-INT note ) – Threshold determination – Calibrate the gain change vs occupancy value – LED can be used Magnetic field to be known Latest reference to be available Calculate / error and the present data gain change, propose gain change on channel where the change is above 2* the expected error. Produce a gain change file – To be translated in HV value Archive the changes – update the reference

Method & dependence For each cell calculate the occupancy ratio : -Threshold to be determined – Precision to be reached 1-2% -Many tests already done by Irina -At Orwell level (monitoring) ->in progress -Tested on raw files from plus..

On line implementation Online info & interference: – Trigger rate plot Spot stable behavior Select events on time basis Source Richard-Frederico – 80hz minimum biais – Magnetic field – – Reference to organize : 2 reference Up & Down At each change update the 2 reference file to the new HV setting Archive – Produce a file for HV On-line team Iouri

Testing & Time scale Adapt the analysis to use it on LED event for testing (if avalable) – Data selection – Calculation – Reference access and storing In parallel threshold determination Goal : this summer