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Dirk Wiedner- On behalf of the LHCb Collaboration. LHC b COMMISSIONING and operation. Physics at the LHC 2010. LHCb Commissioning . CALORIMETERS. Trackers. VErtex LOcator. MAGNET. MUON Detector. RICHes. Outline. HARDWARE installation. The LHCb Experiment Commissioning before Beam

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lhcb commissioning
LHCb Commissioning

CALORIMETERS

Trackers

VErtex LOcator

MAGNET

MUON Detector

RICHes

Outline

HARDWARE installation

  • The LHCb Experiment
  • Commissioning before Beam
  • pp collisions 2009/10
  • Conclusions

TRACKER detectors

Dirk Wiedner on behalf of LHCb

lhcb detector
LHCb Detector

pp Collision December 2009

BEAM2

BEAM1

[zy]

[zx]

Muon

Calorimeters

(ECAL, HCAL)

MAGNET

4 Tm

RICH2

Tracker

(IT,OT)

Acceptance:

15‐250 mrad (V)

15‐300 mrad (H)

 1.9 < η < 4.9

Vertex

(VELO)

RICH1

p

p

Tracker Turicensis

(TT)

p

p

Dirk Wiedner on behalf of LHCb

b j k
B+ J/Ψ K+

Dirk Wiedner on behalf of LHCb

trigger strategy
Trigger Strategy

L0 (up to 1 MHz)

Muon trigger

Calorimeter trigger (electron, photon, hadron)

HLT: computer-farm running full reconstruction

L0 confirmation and vertexing

Up to 2 kHz output

Dirk Wiedner on behalf of LHCb

detector calibration commissioning steps
Detector Calibration: Commissioning Steps

WITHOUT Beam

Test pulse (LED, pulsing systems and radioactive source)

Calorimeters time aligned ~ 1ns

Each Muon half-station internally aligned ~ 3 ns

No relative time alignment between different sub-detectors

Commissioning with Cosmics (started spring 2008)

Detector acceptance and trigger optimized with respect to the interaction point

~ 4 M events collected

Sub-detector relative time alignment

WITH Beam

LHC injection test (started September 2008)

TED Runs: Beam2 dumped on the injection line beam stopper 350 m downstream LHCb

Particles coming from behind the detector and not centered (8 mrad [H] and 12 mrad [V])

Time alignment between sub-detectors ~1 ns

Spatial alignment

Beam-gas interactions

WITH Collisions

450 GeV fills (2009)

3.5 TeV fills (2010)

2008 cosmics data

OUTER TRACKER

MUON

CALORIMETERS

Dirk Wiedner on behalf of LHCb

slide7

Proton-proton collisions

Dirk Wiedner on behalf of LHCb

slide8

Velo

Velo sensors all powered

With 450 GeV beams we could not fully close the Velo

. . . but we see where the beams are

Dirk Wiedner on behalf of LHCb

slide9

Velo

Velo closed for the first time on 1. April

Closing procedure now takes routinely < 15 minutes

Stability in (X; Y ; Z) : (10; 4; 10) μm

PV resolution for track multiplicity of 25

x: ~16 μm

y: ~15 μm

z: ~90 μm

Dirk Wiedner on behalf of LHCb

slide10

Silicon trackers

TT and IT fully operational

Signal to noise ratio as expected

Alignment ongoing

Residual width is 65μm

See Tracking and alignment in LHCb by Florin MACIUC

Dirk Wiedner on behalf of LHCb

outer tracker
Outer tracker

Outer tracker

Drift tubes with TDC

Fully operational

Time and space alignment on a good track

Resolution 276 μm

Drift-time space relation determined

Dirk Wiedner on behalf of LHCb

tracking
Tracking  Λ

~65  μb-1

See Tracking and alignment in LHCb by Florin MACIUC

  • The masses of the reconstructed Λ in agreement with the PDG values
  • Tracking without VELO: tracking detectors were well calibrated at the start-up !
  • Now using full tracking power, including VELO
  • Tracking in good shape for charm and beauty physics

M(Λ) = 1115.74 ± 0.01 MeV/c2

σ = 2.83 ± 0.15MeV/c2

M(ΛPDG) =1115.68 MeV/c2

Dirk Wiedner on behalf of LHCb

riches
RICHes

~65  mμb-1

Preliminary

RICH1

See LHCb particle ID by Philip XING

Kaon ring

Preliminary

RICH2

Kaon ring

With

RICHes

PID!

Beam-Beam December 2009

  • RICH (Ring Imaging CHerenkov)
    • allow K-π identification from ~ 2 to 100 GeV
  • Particle IDentification with RICHes
    • orange points: photon hits
    • Continuous lines: expected distribution for each particle hypothesis

Dirk Wiedner on behalf of LHCb

calorimeter
Calorimeter
  • The calorimeters systems work very effectively, providing the principal trigger at LHCb
  • Time alignment now 1 ns
  • PS/SPD calibration using MIPs
  • ECAL Energy calibration ongoing. Need 50M events to achieve 1% with π0
  • <m> = (135.16 ± 0.02) MeV/c2agreement with the PDG value
  • σ= (6.06 ± 0.03) MeV/c2
  • π0 can be routinely monitored on-line

π0

Dirk Wiedner on behalf of LHCb

slide15
Muon

CALORIMETERs

TRACKERs

Beam-Beam @ 3.5 TeV 2010

See J/Psi results from LHCb by Julien COGAN

Results and prospects for dimuon final states at LHCb by Justine SERRANO

  • Muon system works very well
  • part of L0 trigger
  • Event with dimuons
    • Oppositely charged muon candidates from the interaction region
  • Time resolution in perfect agreement with expectation!
  • J/Ψ peak from dimuon events
    • 12.8 nbarn -1 of data

MUON

J/Ψ

Dirk Wiedner on behalf of LHCb

slide16

LHC/LHCb operation procedure

Fill sequence for physics fill in LHCb:

NO_BEAM

INJECTION

RAMP

PHYS_ADJUST Velo open

PHYSICS Velo closed

DUMP Velo open

End Of Fill

Dirk Wiedner on behalf of LHCb

slide17

LHC/LHCb operation procedure

LHC State

LHCb State

Handshake

HV/LV State

VELO Motion Control

Coming to a screen near you!

Fill sequence for physics fill in LHCb:

NO_BEAM

INJECTION

RAMP

PHYS_ADJUST

PHYSICS

DUMP

End Of Fill

Dirk Wiedner on behalf of LHCb

detector and run control
Detector and Run Control

LHCb PVSS Global Console

  • Run the LHCb detector as a whole from one console
    • All sub-detectors included and operational
    • Detector readout with HLT1 selection
    • Data storage at nominal 2 kHz
  • Detector operated with a unified control software
    • PVSS to control HW and SW processes

LHCb Control Room

Dirk Wiedner on behalf of LHCb

data quality
Data Quality

Data manager

Alarms and errors

Channel maps

Online reconstruction

Trigger control plots

Problem data base

Data quality shift

Express stream

Reconstruction

Data quality group

Stripping of all physics runs

Categorization of runs

Ks

Dirk Wiedner on behalf of LHCb

luminosity
Luminosity

So far 14 nbarn-1

Luminosity will be measured at LHCb with beam gas

LHCb (In-) Efficiency

Dirk Wiedner on behalf of LHCb

conclusions
Conclusions
  • LHCb detector is in good shape!
  • Cosmics data have been very useful for the commissioning of LHCb detector
  • First collisions were used to conclude commissioning
    • higher statistics are now used to fine tune calibrations
  • Intense physics program to fulfill (integrated luminosity ~1 fb-1 in 12-18 months) with many channels to look at…
    • J/y from D or B
    • mixing measurements in the D sector
    • search for CPV
    • Bs m m ; fs from Bs J/y f
    • rare decays (D0mm) in the charm sector
    • And more: CKM-γ, …
  • See also:
  • Status of and news from LHCb by Andrei GOLUTVIN (Imperial College)
  • Tracking and alignment in LHCb by Florin MACIUC
  • LHCb particle ID by Philip XING
  • LHCb first physics results by Olivier SCHNEIDER
  • Minimum bias physics at LHCb by Walter BONIVENTO
  • Charm physics results and prospects at LHCb by Joerg MARKS
  • J/Psi results from LHCb by Julien COGAN
  • Results and prospects for dimuon final states at LHCb by Justine SERRANO
  • Prospects for CP violation at LHCb by Geraldine CONTI

730 members

15 countries

54 institutes

LHCb collaboration

Dirk Wiedner on behalf of LHCb

thanks
Thanks!

730 members

15 countries

54 institutes

LHCb collaboration

Dirk Wiedner on behalf of LHCb

backup
Backup

Dirk Wiedner on behalf of LHCb

trigger
Trigger
  • Level0 hardware trigger 40 MHz  1 MHz
    • ~ 12 MHz visible interaction @ 2•1032 cm-2s-1
    • Search for high pT and ET candidates
      • e, γ, μ, hadron
    • Pile‐up veto
  • High Level Trigger 1 MHz  2 kHz
    • Software trigger
    • HLT1 1MHz  30 kHz
      • Confirms Level0 candidates
      • Vertex and tracker detectors
      • Impact parameter and lifetime cuts
    • HLT2 30 kHz  2kHz
      • Full detector information
      • Inclusive and exclusive selection

Dirk Wiedner on behalf of LHCb

lhcb experiment
LHCb Experiment

bb-bar production along the beam axis

  • Single-arm forward spectrometer dedicated to study b physics
    • bb-bar pairs produced with a high boost are highly forward or backward
  • 2009 run conditions(s1/2 = 900 GeV)
    • Integrated luminosity ~ 7 μb-1
  • Expected conditions next run 2010/11(s1/2 = 7 TeV)
    • Expected integrated luminosity ~1 fb-1 in 12-18 months
  • Nominal Conditions (s1/2 = 14 TeV; L = 2 1032 cm-2 s-1)
    • Integrated luminosity: 2 fb­1/107s

→ ~1012 bb­bar pairs per year

    • Large b cross section ~500 b, about 0.6% of total

Many B, D mesons to study

High background rate

  • Detector requirements
    • Highly selective trigger
    • Good particle identification
    • Good vertex reconstruction

b

θb

_

b

θb

b

_

LHCb Detector

b

BEAM2

BEAM1

Dirk Wiedner on behalf of LHCb

commissioning with cosmics
Commissioning with Cosmics

Muon raw hits acquired with the Calorimeter Trigger

 Muon and Calorimeter are in time for FORWARD tracks

M1

  • Dedicated Level0 trigger selection
    • Muon Trigger
      • Nominal coincidence of 5 stations  ~ 0 Hz rate
      • AND of the two last Muon stations  4 Hz rate
      • Central Muon station alone (M3)  60 Hz rate
    • Calorimeter Trigger
      • Higher Voltage to see MIP  ~ 10 Hz rate
    • No Vertex constraints
    • Open a time window of several bunch crossing centered on the triggered one
      • Time Alignment Event (TAE)
  • Start time alignment between sub-detectors
  • Start commissioning of basic Level0 trigger building blocks!
    • Calorimeters and Muon aligned ~ 3 ns for forward tracks
    • Improvement of Muon Detector internal time alignment
      • r.m.s time distribution from 9 ns (first cosmics 2008) to ~ 4 ns (last measurement 2010)

M2

M3

M4

M5

t (ns)

BACKWARD: not aligned

FORWARD: Time Aligned!

Dirk Wiedner on behalf of LHCb

ted run spatial alignment
TED run: spatial alignment

 VELO, Tracker Turicensis, Inner Tracker detectors  start of spatial alignment

  • Relative Alignment VELO –Tracker Turicensis (TT)
    • expected uncertainty VELO-TT extrapolation: 300 μm
    • hit residual observed in TT: 500 μm
    • offset: 150-300 μm
  • Inner Tracker (IT) alignment ~ 15μm

TT

BEAM2

VELO

IT

Inner Tracker (IT)

BEAM2

Single TED shot

[mm]

Residual for relative Alignment VELO -Tracker Turicensis (TT)

Dirk Wiedner on behalf of LHCb

splash from beam1
Splash from Beam1

CALORIMETER

 Level0 trigger in nominal condition commissioned with BEAM1!!

 Acquired 5 consecutive bunch crossing centered on the trigger event

  • Beam1 on the Target Collimator Tertiary (TCTh)
    • Beam1: correct direction
  • Looking for Halo and splash events
    • Statistics to better align inner regions!

OUTER TRAKER

BEAM1

MUON

September 2008

time

+ 25ns

-50 ns

-25 ns

0 ns

+ 50ns

Readout of 5 bunch crossing centered on the trigger event

Dirk Wiedner on behalf of LHCb

beam gas interactions
Beam – Gas interactions

FORWARD

BACKWARD

  • Beam-Empty bunch crossing:
    • ~ 1 M interaction between beam and the residual gas in beam pipe
  • VErtex LOcator (VELO) reconstructs the interaction beam – gas
    • Retractable detector halves
      • open during injection (30 mm per side)
      • closed in stable beam condition (Ebeam > 2 TeV)

BEAM1 - GAS

BEAM2 - GAS

Beam1-Gas 11/2009: Triggered by Calorimeters OR Muon (rate ~ 5Hz)

Beam2-Gas 11/2009: Triggered by VErtex LOcator: backward silicon stations

VErtex LOcator

21 stations of Silicon strip detector

Dirk Wiedner on behalf of LHCb

beam gas interactions1
Beam – gas interactions

BEAM1

BEAM1

BEAM2

BEAM2

Beam - Gas [XZ] Plane; Crossing Angle

Blue: beam1 – empty

Red: empty - beam2

Green: beam1- beam2 vertex

x (mm)

  • VELO reconstructs the beams crossing angle using beam-gas interactions
  • Impact of LHCb dipole magnet
    • beams cross at 2 mrad angle in [xz] plane as expected at the full magnetic field @ 450 GeV

z (m)

Beam - Gas [YZ] Plane

Dirk Wiedner on behalf of LHCb

commissioning of daq chain
Commissioning of DAQ chain
  • FEST (Full Experiment System Test)
  • Raw-Monte Carlo events injected into the DAQ chain
    • inject @ 2kHz at the High Level Trigger input (limited by Monte Carlo injection)
    • generated 100 M minimum bias (14 hours)
  • Commissioning of:
    • run control
      • run HLT;
      • exercise control/configuration
    • HLT processing
    • online reconstruction and monitoring
      • Histograms relevant to understand problems
    • data storage; data quality
      • Procedure to give the green light
      • interaction with the GRID

Injector

DAQ network

FEST data flow

Data Acquisition Boards

LHCb detector data flow

High Level Trigger Farm

ONLINE and OFFLINE data Monitoring and Processing

1.9 kHz achieved steadily

Dirk Wiedner on behalf of LHCb

lhcb clock phase
LHCb clock phase

LHCb clock to LHC beam phase

temperature dependant

Seasonal and daily time walk

Beam pickup monitor phase measurement

Correction if drift >500ps

Dirk Wiedner on behalf of LHCb