Calo preparation for 2015 Goals: -Trigger stability -Good calibration for HLT2 processing -Improved calibration ( timing, e/gamma response) for all calo sub- detectors -Improved monitoring

Calibration workshop 8/10/2013 The hardware changes : – Damaged Ecal LED fibers will be changed -> improved gain monitoring (Iouri) – Exposed PMT will be replaced ( hundreds) The current calibration scheme for ECAL/PRS – Initial calibration from pi0 fine calibration (D.Savrina) using FMDST available ~ 4 weeks of data taking Minimum biais events. Low energy in PS ~ 80M events needed Iterative procedure The more precise method – Ageing effect corrected from e/p of tagged conversions 55 sets in 2013 (MNM) – Calibration from electron provide also calibration constant also for pre-shower. (O. Steinakin) available only after reconstruction. Analytic solution The current calibration scheme for Hcal – Ageing monitoring through LED response (2012) – PMT change when deviation above certain threshold – Controlled by Cs source run ( every TS) – Fine Hcal calibration on reconstructed data : M events needed to get a cell/cell calibration.

3Yu. Guz 2013/10/09 LED system: HCAL 2012 sum/sum ref, 56 central cells shutdown 137 Cs calibration TS1, 137 Cs calibration TS2, 137 Cs calibration TS3, 137 Cs calibration LED-based HV corrections (17) Cs calibrations (3) results of Cs calibrations at TS is used as a starting point, then LED-based corrections total of 4 Cs calibrations and 17 LED-based corrections Precision of LED corrections is limited by: annealing during TS (and faster ageing afterwards) - PMT rate effect – variation within fill (can be optimized by regrouping PMTs, to be LS1) uncertainty in the “plastic ageing” prediction – non linearity, annealing (the attempts to take the plastic ageing into account are visible)

Occupancy Method & dependence For each cell calculate the occupancy ratio : - Threshold to be determined – Precision to be reached 1-2% Irina Machkhilyan LHCb-INT Calo meeting presentations from Irina in each calo meeting since July

Occupancy ratio #fill dependence MagDownMagup - Depends upon the fill  Stable period in  to be used -Depends of the trigger type -> Minimum biais 85 Hz for 8 hours fill enough to reach a 1% precision - Magup/Magdown reference

Can be extended to Hcal Hcal / LED response Ecal/LED correlated to HV change

PRS case Determination of the integration range complicated By the scale change of the adc spectrum. Checked on data as well.

Method’s checks on 2012 data * Several run used to calculate the correction from occupancy. Bothpolarity Reference are in italic

Ecal E/p fit

Hcal Removing the Hcal HV change effect calculated from LED On raw Hcal fluctuation at 2% level. More investigation on PMTs affecting the trigger The accuracy of the method can be compared to the LED

PS Ecal corrected Ecal +PS corrected E/p for electrons -Ecal occupancy correction applied -Ecal & PS occupancy correction applied -Overcorrection when both are applied: -To be understood -Impact on L0 to be investigated but is expected to be small.

For Hz minimum biais needed ~ 300K /hour – 1 :1.5 % precision all over the calorimeter (10 hours) – 2 consecutive fill can be used – Choose stable  period – Raw information should be available for end of fill processing Built tools able to determine runs with stable mu 2 options – Correction table / cell – HV change – preferred will solve the trigger instability Cannot be reversed PMT HV curves used With new LED system the ageing amplitude can be monitored and used to cross check occupancy changes. Initial calibration needs other methods –  0 (Ecal) – Electrons (Ecal +PS)

Is it possible ? Need 85Hz of minimum biais event to calculate occupancy cell by cell ( occupancy farm ?) Analyse events only in mu stable condition Reference depends upon the magnetic field The PMT HV can be updated when the deviation > 2-sigma of its resolution Possible to check the agreement with LED measurement (Ecal & Hcal) This method had been used in November 2012 to update Ecal HV It will remove the ageing dependance from trigger Is it possible to fit with the new HLT1/HLT2 scheme It has to be completed by fine calibration To be checked in event replaying mode. ( 1st 2014 half)

Data quality controls Improved data quality to point wrong behavior: – On line (in investigation) : The possibility to use the 85 Hz mimimum biais event to check the pi0 mass reconstruction as done in the fine calibration: with or without iterative procedure – e/p per zone for conversion to become standard plots – Pi0 Mass /zone will also become standard DQ plots – e/p on hadronic charged tracks Current developement ( available in 2014) – Retuning of all corrections for electrons and pions – Clustering (2x2 investigate for the upgrade ) Initial precise calibration will come from pi0, electrons, hadrons: FMDST scheme still needed.

spares

2012 procedure Reference calibration from reconstructed  0 – Processing using the current calibration – Extract correction coefficient (Dasha) Need FMDST to be available Processing 2 weeks All 1 Reference used

Ageing trend general Lumi (pb -1 ) The correction are dominated by the higher flux in each zone. They correspond to higher ageing. HV change end of august ~1% /100pb-1 HV change: occupancy method End of November. Back to initial calibration. ~0.4%/100pb-1 Annealing effect : Christmas stop 4% annealing in average Fraction gain lost

E/p for electron (O.Steniakin) Fine calibration applied on already calibrated data

HCAL E/p calibration: track selection For all tracks from Rec/Track/Best : v find associated cells in HCAL, ECAL, PS laying at the track extrapolation; calculate E(HCAL), E(ECAL), E(PS)  using the CaloEnergyForTrack tool (Vanya) (AddNeighbors=1) v keep only tracks with E(HCAL)>0 v require isolation in HCAL (no HCAL cells associated with given track is shared with any other track); v keep only long tracks, -200<z<400mm v reject muons (tight and loose) v reject protons (by RICH): the HCAL responses to and differ, which distorts calibration v require E(ECAL) < 800 MeV && 0< E(PRS) < 20, to reject showers started much before HCAL The track position in HCAL is defined as the position of a cell with max energy deposition. v further refinement:  cut on p track : 7 GeV for all cells, somewhat higher for the innermost ones  (safety) cut on E(HCAL): 2.5 GeV for all cells, somewhat higher for the innermost ones Yu. Guz 2013/10/0919

HCAL response to hadrons, data More uniform than response to muons: ~4% RMS for both inner and outer (borders excluded). Yu. Guz 2013/10/0920