CMS Pixel Detector Upgrade Neeti Parashar Purdue University

CMS Pixel Detector Upgrade Neeti Parashar Purdue University Calumet USA On behalf of the CMS Collaboration N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011

LHC: The Large Hadron Collider Jura mountains The LHC 27 km in circumference 8. 6 km across CMS Lake Geneva airport LHCb ALICE France ATLAS CERN main site Switzerland Ø 27 km ring, 1232 superconducting (1. 9 K) dipoles Ø p − p collider, 7 Te. V each beam Ø nominal luminosity 1034 cm− 2 s− 1, rate 40 MHz Ø study the known particles and their interactions, and look for new particles/interactions Ø Selection of 1 event in 10, 000, 000 (Higgs Boson) N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 2

Compact Muon Solenoid SUPERCONDUCTING COIL CALORIMETERS ECAL Scintillating Pb. WO 4 Crystals HCAL Plastic scintillator copper sandwich Total weight : 12, 500 t Overall diameter : 15 m Overall length : 21. 6 m Magnetic field : 4 Tesla IRON YOKE TRACKERs MUON ENDCAPS MUON BARREL Silicon Microstrips Pixels Resistive Plate Drift Tube Chambers (DT) Chambers (RPC) N. Parashar DPF 2011@Brown University, RI Cathode Strip Chambers (CSC) Resistive Plate Chambers (RPC) 9 -13 August, 2011 3

LHC Runs Ø Design Paramaters for data-taking Ø Proton-proton collisions Ø s = 14 Te. V, L=1034 cm-2 s-1 Ø Crossing rate 40 MHz (25 ns) Ø Lead-Lead Collisions Ø s = 5. 5 Te. V, L=1027 cm-2 s-1 Ø Data Taking in 2010 – 2011 Ø p-p collisions Ø √s = 7 Te. V Ø Long Physics Run Lpeak=1032 cm-2 s-1 Ø Pb-Pb collisions Ø Ended the first successful Heavy Ion Run: 6 Dec 2010 N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 4

Challenge Experimental and Technological Ø 1 billion proton-proton interactions per second Ø Bunches, each containing 100 billion protons, cross 40 million times a second Ø Large Particle Fluxes Ø ~ thousands of particles stream into the detector every 25 ns Ø large number of channels (~ 140 M ch) Ø ~ 1 MB/25 ns i. e. 40 TB generated per second ! Ø High Radiation Levels Ø radiation hard (tolerant) detectors and electronics Extreme requirements in several domains N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 5

CMS Pixel Detector Pixel Size: 150 x 100 μm Sensors: n-on-n Silicon, 260 -300 μm Bump-bonded to PSI 46 Read Out Chips (ROC) Ø Barrel Pixels (BPix) Ø Forward Pixels (FPix) Ø 3 layers at r=4. 3, 7. 2, 11. 0 cm Ø 48 M pixels, 11520 ROCs Ø 1120 Readout links Ø 4 disks at z=± 34. 5, ± 46. 5 cm Ø 18 M pixels, 4320 ROCs Ø 192 Readout links 100 cm 55 cm 30 cm N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 6

CMS Pixel Detector Ø 66 million channels Ø 1. 06 m 2 area Ø Provides precise vertexing and track-finding Ø 3 -hit (2 -hit) coverage for |η|<2. 1 (|η|<2. 5) N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 7

Modules of the Pixel Detector BPix has 768 modules Modules of the Barrel Pixel Detector FPix has 672 modules Panels of the Forward Pixel Detector N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 8

Barrel Pixel N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 9

Forward Pixel N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 10

Installation in CMS: July 08 9/15/2020 N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 11 11

Upgrade Ø SLHC: Upgrade of LHC, called Super-LHC Ø Phase I: L = 2 x 1034 cm-2 s-1 Ø Phase II: L = 1 x 1035 cm-2 s-1 1032 cm-2 s-1 1033 cm-2 s-1 1034 cm-2 s-1 1035 cm-2 s-1 CMS LHC SLHC Ø Challenges Ø Higher Occupancy Ø Radiation Damage N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 12

Upgrade Challenge 2016: start of high-luminosity LHC Phase 1 up to L = 2 x 1034 cm-2 s-1 Ø keep high hit detection efficiency Ø prevent data losses in ROC Ø e. g. for BPIX_1, losses are 16% (50 PU) and 50% (100 PU) Ø keep good track seeding and pattern recognition performance Ø assure 4 -hit coverage over all pseudorapidity acceptance Ø provide high track parameters resolution Ø reduce passive material in tracking volume Ø reduce radius of innermost layer Ø increase radial acceptance Ø radiation damage issue for late Phase 1 run luminosity challenges N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 13

The Upgraded Pixel Detector Ø Ø New Geometry New readout chip with enhanced features New cooling system based on two-phase CO 2 New powering system based on DC-DC converters 4 Layer Barrel and 3 Forward Pixel Disks N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 14

Barrel Pixel Upgrade present detector Ø Ø Ø 3 cylindrical layers innermost layer R = 44 mm outermost layer R = 102 mm 770 modules with 48 M pixels half modules at half-shell boundary total layer 1 mechanics (support + cooling pipes + C 6 F 14) ~ 400 g N. Parashar upgraded detector Ø Ø Ø 4 cylindrical layers innermost layer R = 39 mm outermost layer R = 160 mm 1200 modules with 80 M pixels only one module type (8 x 2 ROCs) total layer 1 mechanics (support + cooling pipes + CO 2) ~ 100 g DPF 2011@Brown University, RI 9 -13 August, 2011 15

Forward Pixel Upgrade present detector upgraded detector Ø 2 disks in each endcap Ø One ring per half disk Ø 3 disks in each endcap Ø Two concentric rings (inner and outer) for easy replacement Ø 672 modules with 45 M pixels Ø 672 modules with 18 M pixels Ø Module design specific for FPIX Ø Same module as barrel (8 x 2 ROCs) N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 16

Material Budget Reduction N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 17

Pixel Upgrade Performance N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 18

Vertex Resolution Improvement N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 19

Impact parameter resolution N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 20

b-tagging performance N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 21

Summary Ø LHC is working fantastic Ø CMS is working as expected Ø CMS Pixel Detector is efficient Ø CMS Pixel Detector Upgrade is in progress Ø WE ARE DOING GREAT PHYSICS DISCOVERIES ARE AROUND THE CORNER ! N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 22

BACKUP SLIDES N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 23

The LHC Design Parameters Nh = number of proton per bunch nb = number of bunches frev = rotation frequency (~ 11 Hz) F = crossing angle factor Rms transverse beam size =√εβ/γ εn = renorm. transverse emittance β* = optics at beam crossing (m) γr = relativistic factor Cost 3 G€ N. Parashar 3. 2 x 1014 p/beam 25 ns between crossing IP 1: ATLAS IP 5: CMS IP 2: ALICE IP 8: LHCb DPF 2011@Brown University, RI 9 -13 August, 2011 24

LHC and CMS operations Ø About 47 pb-1 delivered by LHC and ~43 pb-1 of data collected by CMS Ø Overall data taking efficiency ~92% at √s = 7 Te. V energy L≈ 2 x 1032 cm-2 s-1 L≈ 1027 cm-2 s-1 N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 25

Pixel Detector Efficiency Barrel: 99% 11400 out of 11520 ROCs operational PIXEL TRACKER Endcap: 96. 9% STRIP TRACKER 4185 out of 4320 ROCs operational PRE-SHOWER ECAL END-CAP ECAL BARREL HCAL FORWARD HCAL ENDCAP HCAL BARREL MUON-RPC MUON-DT MUON-CSC 90 91 92 93 94 95 ECAL 96 PRE 97 STRIP 98 PIXEL 99 HCAL ECAL MUON- MUONBARRE ENDCA FORW BARRE END- SHOW TRACK CSC DT RPC L P ARD L CAP ER ER ER Series 1 98. 5 99. 8 98. 8 99. 9 100 99. 9 99. 3 98. 9 99. 8 98. 1 98. 2 N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 100 26

Underground Cavern N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 27

CMS installation in the cavern N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 28

Elements of the Detector ECAL HCAL Magnet Tracker (Microstrip+ Pixel) Muon chambers N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 29

CMS Detector Closed N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 30

Pixel Readout Chip Ø PSI design, manufactured by IBM Ø 0. 25 μm process, ~1. 3 million transistors Ø 15840 ROCs, 4160 pixels/ROC Ø Automatic zero-suppression Ø Double column drain architecture Ø Hits buffered until trigger decision arrives Ø Single 25 ns-wide bunch-crossing readout Ø 40 MHz analog readout Ø Analog pulse height Ø Other info encoded in analog signal Ø e. g. hit pixel address in base-6 N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 31

Module Readout Ø On receiving a L 1 trigger, the Token Bit Manager (TBM) initiates a Chinese-whisper of “token bits” that instruct each ROC to send its hit data to the TBM Ø The signal from the TBM is electrical and analog. It encodes the ROC #, row and column and charge collected of each pixel hit Ø The electrical signal from the TBM is converted to optical by the Analog-Optical Hybrid (AOH) N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 32

Digitizer and Data Readout D A Q Ø Pixel Front End Driver (FED) digitizes analog signals given the level thresholds for decoding. Ø One crate of FED boards is controlled by one Pixel. FEDSupervisor application. Ø 3 crates for a total of 40 FEDs in Pixels. Ø FEDs send digitized data down S-Link cables to the Data Acquisition System (DAQ). Ø FED data may also be read out via VME by the Pixel. FEDSupervisor. Ø Diagnostic information N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 33

Controller Ø Control signals consist of Ø Clock & L 1 Trigger Ø I 2 C Commands for programming Ø Using I 2 C commands we can program various DACs on each ROC, set trim bits on each pixel and inject charges for calibration purposes. N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 34

Primary Vertex Reconstruction N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 35

Primary Vertex Resolution Ø Data Driven : 2 Vertex Method Ø Fit vertex with 2 separate sets of tracks Ø Look at differences between fit vertices Ø Cuts to equalize # tracks, select main primary Ø Use stand-alone Pixel Vertices along beam Ø Tracks within 10 sigma of pixel vertex Ø Agreement is encouraging N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 36

Neutral Kaon Reconstruction Ø Dual Gaussian Fit, no systematic included N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 37

Cascade Reconstruction Ø Low momentum and hits in the pixel N. Parashar DPF 2011@Brown University, RI 9 -13 August, 2011 38