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1/14/08 NTU, Taipei The CMS Detector 1 Paoti Chang National Taiwan University Workshop on LHC Physics and the Strategies for Discovery Taipei, Taiwan,

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Presentation on theme: "1/14/08 NTU, Taipei The CMS Detector 1 Paoti Chang National Taiwan University Workshop on LHC Physics and the Strategies for Discovery Taipei, Taiwan,"— Presentation transcript:

1 1/14/08 NTU, Taipei The CMS Detector 1 Paoti Chang National Taiwan University Workshop on LHC Physics and the Strategies for Discovery Taipei, Taiwan, Jan. 14, 2008

2 The CMS Detector2 1/14/08, NTU, Taipei Detector Requirement Good Muon identification;good dimuon mass resolution (~1% at 100 GeV); distinguish charge at 1 TeV. Good momentum resolution for charged tracks. Efficient triggering and off-line tagging on  and b-jets. Good EM energy resolution; good diphoton and dielectron mass resolution;  wide geometrical coverage;    rejection and efficient photon and lepton isolation Good missing-transverse-energy and dijet mass resolution  high-field solenoid, full-silicon-based inner tracking system and a homogenous scintillating-crystal-based electromagnetic calorimeter

3 The CMS Detector3 1/14/08, NTU, Taipei Overview of the CMS Detector

4 The CMS Detector4 1/14/08, NTU, Taipei Superconducting Magnet Special features: 1. Winding composed of four layers 2. Mechanically reinforced with aluminum alloy 3. Large dimension 6.2 m cold bore, 12.5m length,220-t mass

5 The CMS Detector5 1/14/08, NTU, Taipei Main parameters CMS decides to use lower field, 3.8T.

6 The CMS Detector6 1/14/08, NTU, Taipei CMS Barrel Yoke ready for coil and muon Detector

7 The CMS Detector7 1/14/08, NTU, Taipei Inner Tracking System Provide precise measurements of track trajectories and secondary vertices. L= cm  s   1000 particles from >20 inter. high granularity and fast response of electronics Keeping minimum amount of material 3 layers of pixel to reduce occupancy ( cm) 10 layers of silicon strip detectors (R ~ 1.1 m) endcaps: 2 disk pixel and 3 plus 9 strip on each side ⇕

8 The CMS Detector8 1/14/08, NTU, Taipei Overview of the tracker layout Acceptance |  |<2.5, 200 m 2 silicon area, 1440 pixel and strip modules. pixel: 100x150  m 2 ; Inner silicon: 10cm x 80  m; outer silicon: 25cm x 180  m

9 The CMS Detector9 1/14/08, NTU, Taipei Expected Hadron Fluence and Radiation Dose L = 500 fb , 10 years of LHC running Surface damage on readout chips  0.25  m CMOS chip (rad. hard) Increasing leakage current  low temperature -10  C to -27  C transient phenomena

10 The CMS Detector10 1/14/08, NTU, Taipei Pixel Detector Layout overview barrel support structure material budget 

11 The CMS Detector11 1/14/08, NTU, Taipei Barrel Pixel Detector Modules

12 The CMS Detector12 1/14/08, NTU, Taipei Forward Pixel Half cylinders Sketches of two types of FPix panels Sketch of of a plaquette mounted in a panel

13 The CMS Detector13 1/14/08, NTU, Taipei Status of Pixels

14 The CMS Detector14 1/14/08, NTU, Taipei Overview of Silicon Strip Detector

15 The CMS Detector15 1/14/08, NTU, Taipei Silicon sensor Active region 320  m sensors 500  m sensors

16 The CMS Detector16 1/14/08, NTU, Taipei Silicon Tracker Exploded views of a module of two sensors Inner Barrel and Endcap Three TIB modules in a shell

17 The CMS Detector17 1/14/08, NTU, Taipei Outer Silicon Tracker Each sector consists of 9 front petals and 9 back petals Endcap outer silicon strip detectors TOB wheel d = 2.3 m

18 The CMS Detector18 1/14/08, NTU, Taipei Rod an Petal Double sided rod Front and back panels for TEC

19 The CMS Detector19 1/14/08, NTU, Taipei Expected Performance Impact parameter in r Impact parameter in zTransverse momentum

20 The CMS Detector20 1/14/08, NTU, Taipei Electromagnetic Calorimeter The CMS ECAL consists of a hermetic homogenous calorimeter made of lead tungstate (PbWO 4 ) crystals in the central barrel part, ~7324 crystals in each of the two endcaps, and a preshower detector in front of the endcap crystals. Advantages of PbWO 4 : 1. high density (8.28 g/cm 3 ); 2. shorter rad. Length (.89 cm) 3. short Moliere radius (2.2 cm); 4. fast radiation decay time (80% of the light in 25 ns)  fine granularity, radiation hardness and compact calor.

21 The CMS Detector21 1/14/08, NTU, Taipei CMS-PbWO 4

22 The CMS Detector22 1/14/08, NTU, Taipei Layout of the CMS ECAL Barrel: |  | < fold in  2x85 fold in   crystal size:  front: 22x22 mm 2  back: 26x26 mm 2  length: 230 mm  25.8 X 0 Endcap: 1.479< |  | < unit = 5x5 crystals. crystal size: front: 28.62x28.62mm 2 back: 30x30 mm 2 length: 220 mm 24.7 X 0

23 The CMS Detector23 1/14/08, NTU, Taipei ECAL Modules Module of 200 crystals Barrel supermodule (1700 crystals )

24 The CMS Detector24 1/14/08, NTU, Taipei ECAL-Barrel

25 The CMS Detector25 1/14/08, NTU, Taipei Preshower Detector 1.653<|  |<2.6; total length 20 cm. Twp parts: lead radiators and silicon strip sensors. Taiwan involvement: NCU: 1/4 silicon sensors NTU: System Motherboards

26 The CMS Detector26 1/14/08, NTU, Taipei Calibration and Resolution channel-to-channel variation: use lab. measurements on light yields and photo-dio. response.  5% in barrel and 10% in endcap Beam test  0 /  →  in data; w →e. Laser Monitor system Energy resolution

27 The CMS Detector27 1/14/08, NTU, Taipei Performance of a typical 3x3 crystals

28 The CMS Detector28 1/14/08, NTU, Taipei Status of ECAL Endcaps & Preshower Preshower: testing micro modules, motherboards and preparing to install in April

29 The CMS Detector29 1/14/08, NTU, Taipei Longitudinal View of the CMS Det. HCAL Barrel HCAL EndcapHCAL Forward

30 The CMS Detector30 1/14/08, NTU, Taipei HCAL Barrel (HB) The HB consists of two half-barrels, each of which contains 18 wedges. Each wedge corresponds to 4  sectors. The absorber consists of a 40-mm thick front steel plate, mm-thick brass plates, mm-thick brass plate, and a 75-mm-thick steel back plate. Half barrel wedge 16  5.82 I at 90  and 10.6 I at  =1.3

31 The CMS Detector31 1/14/08, NTU, Taipei The HCAL Tower Segmentation Plastic scintillators

32 The CMS Detector32 1/14/08, NTU, Taipei Endcap Calorimeter (HE) Yoke Close to magnet, non- conducting absorber has to be used. C26000 cartridge brass 

33 The CMS Detector33 1/14/08, NTU, Taipei HCAL Endcaps HE Wedges Scintillator Tray

34 The CMS Detector34 1/14/08, NTU, Taipei Forward Calorimeter Situate at |  | = 5 Detect particles through its Cherenkov light. Require good EM response (electrons). Serve as luminosity monitor Methods: zero counting and average E T per tower

35 The CMS Detector35 1/14/08, NTU, Taipei Expected Performance Jet energy resolution

36 The CMS Detector36 1/14/08, NTU, Taipei Muon System Identify muons, measure momentum and trigger muon events. The muon system consists of three types of gaseous detectors: 1. four layers of drift tubes in |  |< cathode strip chamber covering |  | to resistive plate chambers 6 layers in barrel and 3 in endcaps ( |  | < 1.6 )

37 The CMS Detector37 1/14/08, NTU, Taipei Layout of Drift Tube Chambers One of the five wheels. 60 chambers in the first three layers and 70 in the last. One layer is inside the yoke, one is outside, and the other two are embedded within the york.

38 The CMS Detector38 1/14/08, NTU, Taipei Sketch of Drift-Tube Cell Top and bottom plates are grounded. The voltages applied to the electrode are +320V for wires, V for the strips and V for the cathode. Gas: 85% Ar + 15% CO 2

39 The CMS Detector39 1/14/08, NTU, Taipei Installation of MB1 on Wheel 2 Each DT chamber is made of 3 (or 2) superlayers, each of which is made of 4 layers of rectangular drift cells.

40 The CMS Detector40 1/14/08, NTU, Taipei Quarter view of the CMS Detector

41 The CMS Detector41 1/14/08, NTU, Taipei Layout of a CSC & a Schematic View of a Single Gap 7 trapezoidal panels forming a 6 gas gaps. Gas: 40% Ar + 50% CO % CF 4 HV: kV

42 The CMS Detector42 1/14/08, NTU, Taipei Resistive Plate Chamber Advantage: tagging the ionizing time much shorter than 25  s  good for triggers Gas: 96.2% C 2 H 2 F % C 2 H % SF 6

43 The CMS Detector43 1/14/08, NTU, Taipei Schematic Layout for Barrel RPC r-  view

44 The CMS Detector44 1/14/08, NTU, Taipei Layout for Endcap RPC

45 The CMS Detector45 1/14/08, NTU, Taipei Expected Performance

46 The CMS Detector46 1/14/08, NTU, Taipei Status of the Muon System 1.DT muons: a. Install tower electronics b. Test and commission 2. CSC a. All chambers and electronics are installed. B. Do more tests.

47 The CMS Detector47 1/14/08, NTU, Taipei Summary After so many year hardwork, majority of the detector and electronics are installed and commissioned. Problems and difficulties are foreseen before collisions. Tight schedule for Endcap ECAL and Preshower. Keep testing and looking forward to LHC physics.

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