# Presentation: 604626

## The DØ Detector for Run II

**The DØ Detector for Run II**

- Levan Babukhadia

- SUNY at Stony Brook
- for the DØ Collaboration

## Physics Challenges  The Upgraded Tevatron

**Physics Challenges ******** The Upgraded Tevatron**

- Peak Lum. achieved over 2 1031 cm2s1
- Planned to reach Run 2a design
- by Spring 2003

- Physics goals for Run 2
- precision studies of weak bosons, top, QCD, B-physics
- searches for Higgs, supersymmetry, extra dimensions, other new phenomena
- require
- electron, muon, and tau identification
- jets and missing transverse energy
- flavor tagging through displaced vertices and leptons
- luminosity, luminosity, luminosity...

## Physics Challenges  The Upgraded Detector

- Upgraded Calorimeter electronics readout and trigger

- Added PreShower detectors, Central (CPS) and Forward (FPS)
- Significantly improved Muon System
- New forward proton spectrometer (FPD)
- Entirely new Trigger System and DAQ to handle higher event rate

**Physics Challenges ******** The Upgraded Detector**

## Calorimeters

- LAr in gap
-    2.3 mm

**Ur absorber**

- Readout Cell
- Cu pad readout on 0.5 mm G10 with resistive coat epoxy

- Drift time ~430 ns

- North End Cap

- South End Cap

- Central Cal.

**Calorimeters**

- Liquid Argon sampling
- uniform response, rad. hard, fine spatial segmentation
- LAr purity important
- Uranium absorber (Cu/Steel CC/EC for coarse hadronic)
- nearly compensating, dense  compact
- Uniform, hermetic with full coverage
- |****| < 4.2 (  2o), int ~ 7.2  (total)
- Single particle energy resolution
- e: ****/E = 15% / E  0.3%   : ****/E = 45% / E  4%

- 50k readout cells (< 0.1% bad)
- Fine segmentation
- 5000 pseudoprojective towers ( 0.1  0.1 )
- 4 EM layers, shower-max (EM3): 0.05  0.05
- 4/5 Hadronic ( FH + CH )
- L1/L2 fast Trigger readout 0.2  0.2 towers
- Fully commissioned

## Calorimeter Performance

- Three-jet event
- ETjet1 ~ 310GeV, ETjet2 ~ 240GeV
- ETjet3 ~ 110GeV, ET ~ 8GeV

- Z  ee employed
- for EM calibration

- ET from multijet data

**DØ Run 2 Preliminary**

- (ET)~7GeV

- Present performance
- of (ET) from incl.   di-electrons with at least one track match (mainly Z, Drell-Yan)

**Calorimeter Performance**

## Muon System

- _Fully commissioned_

-  Central and Forward regions, coverage up to  = ± 2
-  Three layers: one inside (*A*), two outside (*B*, *C*) the toroid magnets
-  Consists of scintillators and drift tubes
-  Central Proportional Drift Tubes (PDT’s)
-  6624 drift cells (10.1  5.5 cm) in 94 three- and four-deck chambers
-  Central Scintillation Counters
-  360 “cosmic ray” counters outside the toroid ( = 22.5)
-  630 “A” counters inside ( = 4.5),  = 0.1
-  Forward Mini Drift Tubes (MDT’s)
-  6080 8-cell tubes in 8 octants per layer on North and South side, cell cross-section 9.4  9.4 mm
-  Forward Scintillation Counters (Pixels)
-  4214 counters on the North and South side
-   = 4.5 matches the MDT sector size

## Muon System Performance

- Muon Timing

- Cosmic rays

- ’s from Collisions

- Timing cuts reduce cosmic bckg., could aid in detection of slow moving particles

- Z  +
- candidate

- Muon stand alone system

- Muon plus central tracking

- J/ invariant mass

- Matching of central tracks to ’s
- improves momentum resolution

***CHEP02 – 31******st****** International Conference on High Energy Physics, Amsterdam, 24 – 31 July, 2002***

- Levan Babukhadia

- ICHEP02 – 31st International Conference on High Energy Physics, Amsterdam, 24 – 31 July, 2002

## DØ Forward Proton Detector

-  Routinely insert pots during collisions
-  Recorded > 2 M elastic events with stand-alone DAQ
-  Working on integration of FPD with the rest of DØ
-  First diffractive+jet data by December

**DØ Forward Proton Detector**

-  Diffractive and elastic physics program
-  need special detectors at very small angles: FPD
-  FPD consists of 2 arms (outgoing proton and anti-proton)
-  18 Roman pots in 4 quadrupole and 2 dipole “castles”
-  From hits in scintillating fiber detectors installed in Roman pots
-  fractional energy lost by the proton and scattering angle
-  trigger on elastic, diffractive, double pomeron events

**Dipole Castle**

## DØ Trigger System

_**Level 1**_
- Subdetectors
- Towers, tracks, clusters, ET
- Some correlations
- Pipelined

_**Level 2**_
- Correlations
- Calibrated Data
- Separated vertex
- Physics Objects e, , j, , ET

_**Level 3**_
- Simple Reconstruction
- Physics Algorithms

- Entire Trigger Menu configurable and downloadable at Run start
- Trigger Meisters provide trigger lists for the experiment by collecting trigger requests from all physics groups in the Trigger Board
- All past and present trigger lists are stored and maintained in the dedicated trigger database

## DØ Track and Preshower Digital Trigger

-  Implemented in ~100 digital boards with same motherboard and different flavors of daughter-cards with over 500 Xilinx Virtex FPGAs
-  Provides charged lepton id in Level 1 by finding tracks in 4.5 azimuthal trigger sectors of CFT
-  Helps with EM-id in Level 1 by reconstructing clusters of energy in CPS scintillator strips
-  Helps with Muon-id in Level 1 by sending 6 highest pT tracks to L1Muon in about 900ns
-  Helps with EM-id in forward regions || < 2.6 by reconstructing clusters of energy in FPS strips
-  Helps with charged lepton id in forward regions by confirmation in pre-radiator layers of FPS
-  Facilitates matching of preshower and calori-meter objects at quadrant level
-  Helps with displaced vertex id in Level 2 Silicon Track Trigger by providing the Level 1 CFT tracks for global SMT+CFT track fitting
-  Currently being commissioned

**DØ Track and Preshower Digital Trigger**

## Data Acquisition System

- ~250 kB/event

- Gathers raw data from the front-end crates following each Level 2 Accept
- Based on “off the shelf” components
- Single Board Computers (SBCs) read out Level 3 buffers: Intel 1GHz, VME based, dual 100Mb Ethernet, Linux OS
- SBCs send data to a Level 3 node over fast Ethernet switches according to instructions received from the Routing Master

- The routing Master program runs on an SBC in a special crate receiving data from the Trigger Framework
- Cisco Switch sends data to Linux Level 3 Farm nodes
- Event building and Level 3 trigger selections performed by 48-node Linux farm

## Level 1 and Level 2 Trigger Performance

- Rate (Hz)

-      Luminosity (10**30** cm-2s-1)

- central

- forward

- Level 1 Calorimeter Jet and EM trigger “turn-on”s

- Level 1 Muon trigger rate  dependence on Luminosity

- Level 2 Calorimeter Jet and EM trigger efficiencies

- Level 2 Muon trigger efficiency and rejection

- L2EM(1,10 GeV; EMF > 0.85)

- L2JET(1,10 GeV)

- Jet

- EM

## Level 3 Trigger Performance

- Offline EM ET (GeV)

- 15 GeV L3 EM Trigger Rej.~10 w.r.t. to L1 (10 GeV at L1)
- 12 GeV + shower shape cuts .OR. the above

- The 48-node Linux Level 3 farm working and selecting events, by triggering on Jets, EM objects, Muons, Taus

## DØ Detector Run 2b Upgrade

- Trigger Upgrade
- Upgrade L1 Track Trigger to narrow roads, improve Track-Cal. matching
- Upgrade L1/2 Cal. Trigger to use digital filter, isolation, shape cuts
- Incremental upgrades to Level 2, Level 3 Triggers and online system

- Present detector was designed for ~24fb1 integrated and ~21032 cm2s1 instantaneous Luminosity
- Run 2b goal ~15fb1 before LHC Physics
- Physics motivations: Higgs and Supersymmetry
- Exceeds radiation tolerance of existing Silicon detector
- Requires higher instantaneous luminosities, ~51032 cm2s1, trigger upgrades

- Silicon Upgrade
- Replace Silicon Detector with a more radiation-hard version
- New Silicon tracker with innermost layer at 1.78 cm (c.f. 2.71 in Run 2a)
- Maintain good pattern recognition coverage || < 2

## Summary and Outlook

- The DØ Detector for Run 2 is operating and collecting physics data
- Enormous progress over the past year in installation, integration, commissioning of the detector and understanding the data
- Performance of the Run 2 DØ detector is very encouraging
- all subdetectors are operating well
- software and computing systems are working well
- we are reconstructing electrons, muons, jets, missing ET, J/, W’s and Z’s and first results already presented at winter/spring and now at summer conferences
- We are working hard on what still needs to be done
- complete commissioning of Level 1 Track Trigger
- improve calibration and alignment
- integrate Level 2 Silicon Track Trigger later this year
- optimize detector, trigger, and DAQ performance
- continue working on Run 2b Upgrade Project
- We are on the way to exciting physics, first physics results coming soon, exciting years are ahead!