lhc b commissioning and operation
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
Dirk Wiedner- On behalf of the LHCb Collaboration
LHCb COMMISSIONINGand operation
1
Physics at the LHC 2010
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 2
LHCb CommissioningOutline The LHCb Experiment Commissioning before
Beam pp collisions 2009/10 Conclusions
HARDWARE installation
MUON Detector
VErtex LOcator MAGNET
RICHes
CA
LO
RIM
ET
ER
S
TRACKER detectors
Trackers
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 3
LHCb Detector
Acceptance: 15‐250 mrad (V)15‐300 mrad (H) 1.9 < η < 4.9
p p
MAGNET 4 Tm
[zx]
Vertex(VELO)
Tracker(IT,OT)
Calorimeters(ECAL, HCAL)
MuonRICH2
RICH1
p p
Tracker Turicensis
(TT)
[zy]
BEAM1 BEAM2
pp Collision December 2009
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 4
B+ J/Ψ K+
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 5
Trigger Strategy
L0 (up to 1 MHz)
Muon trigger
Calorimeter trigger (electron, photon, hadron)
HLT: computer-farm running full reconstruction
L0 confirmation and vertexingUp to 2 kHz output
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 6
Detector Calibration: Commissioning Steps
2008 cosmics data
OUTER TRACKER
CALORIMETERS
MUON
WITHOUT Beam1. 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-
detectors2. 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 Beam3. 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
4. Beam-gas interactions
WITH Collisions5. 450 GeV fills (2009)6. 3.5 TeV fills (2010)
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 7
Proton-proton collisions
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 8
Velo sensors all poweredWith 450 GeV beams we could not fully close the Velo. . . but we see where the beams are
Velo
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 9
Velo
Velo closed for the first time on 1. AprilClosing procedure now takes routinely < 15 minutesStability in (X; Y ; Z) : (10; 4; 10) μmPV resolution for track multiplicity of 25
x: ~16 μmy: ~15 μmz: ~90 μm
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 10
TT and IT fully operational
Signal to noise ratio as expected
Alignment ongoingResidual width is 65μm
Silicon trackers See Tracking and alignment in LHCb by Florin MACIUC
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 11
Outer trackerOuter tracker
Drift tubes with TDCFully operationalTime and space alignment on a good trackResolution 276 μmDrift-time space relation determined
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 12
Tracking Λ 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 ± 0.15 MeV/c2
M(ΛPDG) =1115.68 MeV/c2
See Tracking and alignment in LHCb by Florin MACIUC
~65 μb-1
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 13
RICHes
Beam-Beam December 2009
RICH1
RICH2
Kaon ring
Kaon ring
Preliminary
Preliminary
RICH (Ring Imaging CHerenkov)o allow K-π identification from ~ 2 to 100 GeV
Particle IDentification with RICHeso orange points: photon hitso Continuous lines: expected distribution for
each particle hypothesis
With RICHes
PID!
See LHCb particle ID by Philip XING
~65 mμb-1
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 14
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/c2 agreement with the PDG value
σ= (6.06 ± 0.03) MeV/c2
π0 can be routinely monitored on-line
π0
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 15
Muon 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
Beam-Beam @ 3.5 TeV 2010
TRACKERs
CALORIMETERs
MUON
See J/Psi results from LHCb by Julien COGAN
Results and prospects for dimuon final states at LHCb by Justine SERRANO
J/Ψ
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 16
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
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 17
LHC/LHCb operation procedure
Fill sequence for physics fill in LHCb:NO_BEAM
INJECTION
RAMP
PHYS_ADJUST
PHYSICS
DUMP
End Of Fill
VELO Motion Control Coming to a screen near you!
LHC State LHCb State
Handshake
HV/LV State
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 18
Detector and Run Control
Run the LHCb detector as a whole from one consoleo All sub-detectors included and operationalo Detector readout with HLT1 selectiono Data storage at nominal 2 kHz
LHCb PVSS Global Console
LHCb Control Room
Detector operated with a unified control softwareo PVSS to control HW and SW
processes
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 19
Data Quality
Data managerAlarms and errorsChannel mapsOnline reconstructionTrigger control plotsProblem data base
Data quality shiftExpress streamReconstruction
Data quality groupStripping of all physics runsCategorization of runs
Ks
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 20
Luminosity
LHCb (In-) EfficiencySo far 14 nbarn-1
Luminosity will be measured at LHCb with beam gas
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 21
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…o J/ y from D or Bo mixing measurements in the D sector o search for CPVo Bs m m ; fs from Bs J/ y fo rare decays (D0mm) in the charm sectoro And more: CKM-γ, …
730 members15 countries54 institutes
LHCb collaboration
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
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 22
Thanks!
730 members15 countries54 institutes
LHCb collaboration
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 23
Backup
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 24
Trigger1. Level0 hardware trigger 40 MHz 1 MHz
o ~ 12 MHz visible interaction @ 2•1032 cm-2s-1
o Search for high pT and ET candidates• e, γ, μ, hadron
o Pile‐up veto
2. High Level Trigger 1 MHz 2 kHzo Software triggero HLT1 1MHz 30 kHz
• Confirms Level0 candidates• Vertex and tracker detectors• Impact parameter and lifetime cuts
o HLT2 30 kHz 2kHz• Full detector information• Inclusive and exclusive selection
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 25
LHCb Experimentbb-bar production
along the beam axis
b
_b
θb
b
_b
θb
Single-arm forward spectrometer dedicated to study b physicso bb-bar pairs produced with a high boost are highly forward
or backward
2009 run conditions (s1/2 = 900 GeV)o Integrated luminosity ~ 7 μb-1
Expected conditions next run 2010/11 (s1/2 = 7 TeV)o Expected integrated luminosity ~1 fb-1 in 12-18 months
Nominal Conditions (s1/2 = 14 TeV; L = 2 1032 cm-2 s-1)o Integrated luminosity: 2 fb 1/107 s
→ ~1012 bb bar pairs per yearo Large b cross section ~500 b, about 0.6% of total
Many B, D mesons to study High background rate
Detector requirementso Highly selective triggero Good particle identificationo Good vertex reconstruction
BEAM1
BEAM2LHCb Detector
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 26
Commissioning with Cosmics Dedicated Level0 trigger selection
1. 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
2. Calorimeter Trigger• Higher Voltage to see MIP ~ 10 Hz rate
o 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!o 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)
FORWARD: Time Aligned!
BACKWARD: not aligned
t (ns)
M2
M3
M4
M5
M1
Muon raw hits acquired with the Calorimeter Trigger Muon and Calorimeter are in time for FORWARD tracks
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 27
VELO, Tracker Turicensis, Inner Tracker detectors start of spatial alignment
TED run: spatial alignment
Residual for relative Alignment VELO -Tracker Turicensis (TT)
IT
TT
VELO
Relative Alignment VELO – Tracker Turicensis (TT)o expected uncertainty VELO-TT
extrapolation: 300 μmo hit residual observed in TT: 500 μmo offset: 150-300 μm
Inner Tracker (IT) alignment ~ 15μm
BEAM2
BEAM2 Inner Tracker (IT)
Single TED shot[mm]
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 28
Level0 trigger in nominal condition commissioned with BEAM1!!
Acquired 5 consecutive bunch crossing centered on the trigger event
OUTER TRAKER
CALORIMETER
MUON
Splash from Beam1
-50 ns -25 ns 0 ns + 25ns + 50ns
BEAM1
Beam1 on the Target Collimator Tertiary (TCTh)o Beam1: correct direction
Looking for Halo and splash events Statistics to better align inner
regions!
time
Readout of 5 bunch crossing centered on the trigger event
September 2008
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 29
Beam – Gas interactions
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
Beam-Empty bunch crossing:o ~ 1 M interaction between beam and the
residual gas in beam pipe VErtex LOcator (VELO) reconstructs the
interaction beam – gas o Retractable detector halves
• open during injection (30 mm per side)
• closed in stable beam condition (Ebeam > 2 TeV) VErtex LOcator21 stations of Silicon strip detector
FORWARD BACKWARD
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 30
Beam – gas interactions VELO reconstructs the beams
crossing angle using beam-gas interactions
Impact of LHCb dipole magnet o beams cross at 2 mrad angle in [xz] plane as
expected at the full magnetic field @ 450 GeV
x (mm)
z (m)
Blue: beam1 – empty
Red: empty - beam2
Green: beam1- beam2 vertex
Beam - Gas [YZ] Plane
BEAM1 BEAM2
Beam - Gas [XZ] Plane; Crossing Angle
BEAM1 BEAM2
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 31
High Level Trigger Farm
Data Acquisition Boards
ONLINE and OFFLINE data Monitoring and Processing
Injector
FE
ST
da
ta flo
w
LHCb detector data flow
DAQ network
Commissioning of DAQ chain
Commissioning of:o run control
• run HLT;• exercise control/configuration
o HLT processingo online reconstruction and
monitoring• Histograms relevant to understand
problems
o data storage; data quality • Procedure to give the green light• interaction with the GRID
1.9 kHz achieved steadily
FEST (Full Experiment System Test) Raw-Monte Carlo events injected into the DAQ chain
o inject @ 2kHz at the High Level Trigger input (limited by Monte Carlo injection)o generated 100 M minimum bias (14 hours)
LHCb commissioning and operation7 June 2010 Dirk Wiedner on behalf of LHCb 32
LHCb clock phase
LHCb clock to LHC beam phase temperature dependant
Seasonal and daily time walk
Beam pickup monitor phase measurementCorrection if drift >500ps
-2.50-2.00-1.50-1.00-0.500.000.50
[ns]