H C A L 11 th International Conference on Advanced Technology and Particle Physics Villa Olmo (Como - Italy), October 5 - 9, 2009 THE PERFORMANCE OF THE CMS HADRON CALORIMETER with COSMIC MUONS Vasken Hagopian Florida State University/ Note Dame University For the CMS Hadron Calorimeter Collaboration 15 October th International Conference, COMO, Italy

H C A L CERN in Geneva, Switzerland CMS Test Beam 25 October th International Conference, COMO, Italy

H C A L HCAL Detector Performance In 2008 about 300 million cosmic muons were recorded with the 3.8 tesla magnet on called CRAFT (Cosmic Run At Four Tesla) and another 3 million cosmic muons at Zero field (CRUZET). OUTLINE Calibration using ’s Time alignment Electronic noise 35 October th International Conference, COMO, Italy

H C A L The CMS Detector HF HOHB HE 45 October th International Conference, COMO, Italy

H C A L End Cap & HO 55 October th International Conference, COMO, Italy

H C A L STATUS OF HCAL HCAL has various sub-systems: Barrel HB. End Cap HE. Outer calorimeter HO. Forward HF, Very forward CASTOR AND ZDC. This presentation covers only HB, HE and HO. HCAL IS NOW COMPLETELY ASSEMBLED IN CMS. Portions of each subsystem was tested and calibrated in the CERH H2 test beam. 65 October th International Conference, COMO, Italy

H C A L HADRON CALORIMETER FEE are locations of Front End Electronics. Right end of beam line is the intersection point. ECAL modules are inside HCAL and the combined information of ECAL and HCAL determines the hadron energy. IP 75 October th International Conference, COMO, Italy

H C A L COSMIC MUONS 300 million cosmic muons were taken with the CMS magnet on in 2008 and a similar number with the magnet off. In Sept 2008, for a few days LHC circulated 450 GeV/c beam. We observed beam gas events and later the beam was stopped by collimators 150 m from CMS. These “splash” events were used for timing. 85 October th International Conference, COMO, Italy

H C A L Calorimeter Calibration Procedure for calibration: Calibration using both ECAL and HCAL. Step 1 is in the test beam (2006 for HB, HO, HF and 2007 for HE). Using electrons, pions and muons. Radioactive wire sourcing of each tile (HB and HE) before lowering CMS into cavern. Cosmic muons for final calibration before LHC beam. 95 October th International Conference, COMO, Italy

H C A L Cosmic muon energy Cosmic ’s. p = 7 to 300 GeV/c. Not energy corrected 105 October th International Conference, COMO, Italy

H C A L Cosmic muon energy Left: Cosmic momentum distribution Right: Energy loss (dE/dx) vs. p and comparison to expected value 115 October th International Conference, COMO, Italy

H C A L Calibration constants refined using 2008 data. Barrel only data: Pµ = GeV/c. Signal corrected for path length and momentum to 25 GeV/c. Mean response for HB+/HB- is in good agreement 125 October th International Conference, COMO, Italy

H C A L First LHC Beam in 2008 “Splash” Event Wed, 10 Sept “Splash” events observed when beam (450 GeV, 4  10 9 p) struck collimators 150m upstream of CMS Halo muons observed on (uncaptured and captured) started passing through CMS Data-taking with LHC beam. 135 October th International Conference, COMO, Italy

H C A L LHC Beam: Beam Gas Energy Deposit in HE HCAL Endcap: un-captured and RF-captured circulating beam 145 October th International Conference, COMO, Italy

H C A L HCAL Electronic Noise Data Box (RBX) and HPD RBX Noise: noise hits in multiple HPDs in a RBX 40GeV < E < 420GeV HPD Noise: noise hits in only one HPD in a RBX ion feedback (nhits < 10 ) below 40 GeV discharge (nhits>=10) above 420 GeV 155 October th International Conference, COMO, Italy

H C A L Fake Missing Transverse Energy in CRAFT Data 5 October th International Conference, COMO, Italy 16 Algorithms are off line software that reduce the contribution due to noise.

H C A L Timing alignment Laser distribution aligns to a few nsec. Front end electronics can delay time in 1 nsec steps. Time (start) of event depends on event energy. Final alignment adjustment using “splash” events. Time alignment now is about 1 nsec. 175 October th International Conference, COMO, Italy

H C A L Timing Corrections using “Splash” Events 5 October th International Conference, COMO, Italy 18

H C A L Time Filtering 5 October th International Conference, COMO, Italy 19

H C A L SiPM 5 October th International Conference, COMO, Italy 20

H C A L HO Upgrade 215 October 2009 HO measures energy leakage from barrel calorimeter. No direct calibration. Equalization using ’s. Most HPD noise is in HO as axes are not aligned well with magnetic field direction. Investigating SiPM as replacement of HPD’s.

H C A L Other tests HCAL is very stable in time and energy during operation. Zero suppression is effective in reducing data to less than 20% occupancy for nominal luminosity. Splash events confirmed calibration constant that give uniform energy. 5 October th International Conference, COMO, Italy 22

H C A L Physics of CMS Standard model breaks down at E ~ 1 TeV New physics is expected at TeV scale. Dark matter search is critical; Calorimeter required to measure missing energy. Discoveries should revolutionize particle physics and cosmology & provide window to physics at unification scale. 235 October th International Conference, COMO, Italy

H C A L Conclusion HCAL assembly and installation completed. Now initial calibration complete. Final calibration with collisions. CMS will soon start taking data Already working on upgrade for increased luminosity. Scintillators will be damaged and other components will have reduced effectiveness. 245 October th International Conference, COMO, Italy