Frontier Physics at the LHC CMS Physics Week

Frontier Physics at the LHC - CMS Physics Week RPC CRAFT 08 -09 Analysis Results Raffaello Trentadue Università degli Studi di Bari, CERN On behalf of RPC group Bologna, 7 -11 September 2009

CRAFT 08 → CRAFT 09: RPC system The entire RPC system was successfully operated for the first time during CRAFT 09 Many improvements on the hardware reliability and on the run procedures between CRAFT 08 and CRAFT 09 enabled to study the Barrel working point and to improve the understanding of the forward part performance. Hardware grounding improved forward cooling circuit revised grid of sensors T - RH distributed around the detector improved monitoring capability of currents and T Technical Trigger Unit (TTU) successfully integrated and operated CCU ring stability improved CMS RPC group, 09 September 2009 Software I PVSS function extended to monitor full Endcap. DQM certification now available DQM historical plots implemented Additional analysis modules integrated in the Prompt Analysis 2

CRAFT 09: DCS and PVSS DCS proved to be stable. Almost ready to be controlled centrally. A Dedicated RPC Alarm display has been added to spot quickly new warning condition with major severity level CMS RPC group, 09 September 2009 3

CRAFT 08 → CRAFT 09: DQM Certification algorithms are run as part of the DQM histogram harvesting process. The certification decisions is determined per run (in the future per lumisector) based on input from DQM online , DQM offline, DCS, DAQ/RCMS. List of run of any interest for RPCs: https: //twiki. cern. ch/twiki/bin/view/CMS/RPClistof. Run. P 5 CRA FT 09 55% percent of the time working properly 14% of the events taken with non optimal detector conditions Information from RPC Efficiency is added here CMS RPC group, 09 September 2009 4

Detector Operation P 5 -CAF Shifter duties at PT 5 Check that the detector work safely (cooling, gas, smoke, DCS communication) Monitor the stability and the quality of data during the run: 3 shifters/ day at P 5 2 shifters/day at CAF (no night shift) 1 Shifter leader 24/24 5 experts on call 24/24 - Trend of current, temperature (every 8 hours) - Monitor the trigger rate and spikes - Check the data quality for each run (DQM) Shifter duties at CMS center Provide a fast feedback (run by run) to operation group concerning the detector performance thanks to the Prompt Analysis Tool - efficiency with the Stand. Alone track - Occupancy; - Cluster size - offline trigger performance; - Historical DQM: monitoring at the same time the hardware parameters (current, temperature and pressure) and the parameters coming from the analysis (efficiency, noise. cluster size, occupancy). CMS RPC group, 09 September 2009 5

Technical Trigger Unit The TTU has been commissioned and successfully used along CRAFT 09 RPC-HV scan results CMS RPC group, 09 September 2009 6

Current-Temperature monitoring along CRAFT 09 Barrel Tempereature of detectors was within the requirements. Still a few RE chambers almost at the threshold (23°). Endcap The current has been stable along the CRAFT 09 CMS RPC group, 09 September 2009 7

RPC Historical Plots 9300 V 9200 V CMS RPC group, 09 September 2009 9400 V Monitor of RPC distribution of bunch crossing, cluster size, efficiency throught Historical DQM. 8

CRAFT 08 → CRAFT 09: noise For most part of time the amount of masked strips is below 3%. A few runs had problems in the link system → more strips without data. Masking procedure improved in CRAFT 09. CMS RPC group, 09 September 2009 9

Efficiency CRAFT 08 Run 67647 9. 3 k. V 230 m. V CRAFT 09 Run 109578 9. 3 k. V 220 m. V Swapped Cables were corrected Few Single Gap Chambers Better Syncronization CRAFT-08 CMS RPC group, 09 September 2009 CRAFT-09 10

CRAFT 09: HV scan at Th = 210 m. V 8. 8 k. V → 9. 0 k. V → 9. 1 k. V → 9. 2 k. V → 9. 3 k. V → 9. 4 k. V → 9. 5 k. V CMS RPC group, 09 September 2009 11

CRAFT 09: HV scan Example of one barrel chamber HV scan for noise and efficiency at two different thresholds. Red Th. 210 m. V Green Th. 220 m. V At 9. 5 k. V and 210 m. V the noise level is still very low. CMS RPC group, 09 September 2009 12

CRAFT-09: working point HV working point The distribution of HV at 95% of plateau efficiency (knee) has the avarage value at 9. 2 k. V → the suitable HV working point is 9. 3 k. V. A slightly increase of efficiency is observed at 210 m. V. CMS RPC group, 09 September 2009 13

CRAFT 08 → CRAFT 09: muongraphy Improved statistics allows to have high resolution muongraphy CRAFT-08 CMS RPC group, 09 September 2009 CRAFT-09 14

Efficiency – Endcap efficiency working in progress Better skim of tracks to match the topology used for the synchronization. Some CSC-RPC synchronization mismtach needs to be understood 8. 8 k. V → 9. 0 k. V → 9. 1 k. V → 9. 2 k. V → 9. 3 k. V → 9. 4 k. V → 9. 5 k. V Improve the quality of the selected CSC segments used for the extrapolation. CMS RPC group, 09 September 2009 15

The STA extrapolation method The method propagates the Stand Alone Muon tracks through the RPC planes. For each layer the measurement corresponding to the closest DT or CSC Rec. Hit with respect the center of the Roll is considered. A measurement is defined as an object which contains both the fit position estimation and the propagation direction. Then the stepping helix propagator is used to extrapolate on the RPC Layer surface following up the magnetic field. DT Station RPC Layer CMS RPC group, 09 September 2009 16

The STA extrapolation method The residuals distributions for the STA method have a RMS lower than DT extrapolation one. The precision of the extrapolation is higher. The method is not affected by the poor quality of segments. CMS RPC group, 09 September 2009 DT extrapolation STA extrapolation 17

Efficiency with STA method The STA extrapolation method is sensitive to the Skim. Using the CSC skim the efficiency value reachs 83 % → compatible with the segment extrapolation method. Low efficiency still under investigation!!!!!!! Average barrel efficiency at HV = 9. 4 Average endcap RE+2 efficiency at HV = 9. 4 using CMS skim track reconstruction method Average endcap RE+2 efficiency at HV = 9. 4 using only cosmic RECO CMS RPC group, 09 September 2009 18

CRAFT 08: cluster size CMS RPC group, 09 September 2009 19

CRAFT 09: cluster size Cluster size vs High Voltage Cluster size dist at different th. 8. 8 k. V → 9. 0 k. V → 9. 1 k. V → 9. 2 k. V → 9. 3 k. V → 9. 4 k. V → 9. 5 k. V At 9. 3 k. V the cluster size is 2 strips. Moreover there is not change in the mean cluster size between thresholds 210 m. V and 220 m. V. CMS RPC group, 09 September 2009 20

Conclusions The full RPC system has been operated and monitored for the first time during the CRAFT 09. More information with respect to CRAFT 08 are available to study the RPC working point as function of threshold and High Voltage. The Barrel has been improved appreciably with respect to the CRAFT 08. Problem of swapped cable and geometry have been fixed. The low efficiency of the Endcap needs more investigations. Operation procedures at P 5 and CMS Centre are smooth and reliable for the LHC running. CMS RPC group, 09 September 2009 21

Endcap residuals Residuals considering the skimming produced for the CSCs study. A higher quality is selected since at least two CSC segments are required in the events. CMS RPC group, 09 September 2009 22