C. Deplano#+#On#behalf#of#the#LHCb#Collabora4on# LHCb ...moriond.in2p3.fr/QCD/2010/SundayMorning/Deplano.pdf · (VELO) Tracker (IT,OT) Calorimeters (ECAL, HCAL) Muon RICH2 RICH1 p

C. Deplano -‐ On behalf of the LHCb Collabora4on

LHCb COMMISSIONING

1

LHCb Commissioning /24

LHCb Commissioning Outline   The LHCb Experiment   Commissioning Steps

o  Cosmics o  Beam: injection test

  Results from beam-gas interactions and firsts pp collisions

  Conclusions

3/14/10 Caterina Deplano -‐ Rencontres de Moriond QCD 2

HARDWARE installation

MUON Detector

VErtex LOcator MAGNET

RICHes

CA

LOR

IME

TE

RS

TRACKER detectors


LHCb Experiment


bb-bar production along the beam axis

b

_ b

θb

b

_ b

θb

  Single-arm forward spectrometer dedicated to study b physics o  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 year

o  Large b cross section ~500 µb, about 0.6% of total

Many B, D mesons to study

High background rate

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

LHCb Detector

LHCb Commissioning /24 3/14/10 Caterina Deplano -‐ Rencontres de Moriond QCD 4

[zy]

BEAM1 BEAM2

LHCb Detector Acceptance: 10‐250 mrad (V) 10‐300 mrad (H) 1.9 < η < 4.9

p p

MAGNET 4 Tm

[zx]

Vertex (VELO)

Tracker (IT,OT)

Calorimeters (ECAL, HCAL)

Muon RICH2

RICH1

p p

Trigger Tracker (TT)

pp Collision December 2009


Trigger 1.   Level0 hardware trigger 40 MHz 1 MHz

o  ~ 12 MHz visible interaction o  Search for high pT and ET candidates

•  e, γ, µ, hadron

o  Pile‐up veto

2.   High Level Trigger 1 MHz 2 kHz o  Software trigger o  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



Detector Calibration: Commissioning Steps


WITHOUT Beam

WITH Beam

1.  Test pulse (LED, pulsing systems and radioactive source) o  Each sub-detector individually Check of connectivity and mapping the dead/noisy channels Internal time/space alignment of each sub-detectors

2.  Commissioning with Cosmics (started spring 2008) o  Even if the cosmics rate related to the LHCb geometrical acceptance in a 100 m

underground cavern is < 1 Hz/m2, cosmics are still useful!

o  Cosmics cross 3 main detectors: Calorimeters, Muon and Outer Tracker (OT)   Start of time alignment among different sub-detectors   Start of the Level0 hardware trigger commissioning

3.  LHC injection test (started September 2008) o  Sub-detectors: Vertex (VELO) and Trackers (IT, TT), RICH2, Calorimeters, Muon   Start of spatial alignment   Continue time alignment among sub-detectors

4.  Beam-gas interactions and beams collision (started autumn 2009) o  All sub-detectors Tune calibrations and firsts commissioning results




WITHOUT Beam

WITH Beam





3.  LHC injection test (started September 2008) o  Sub-detectors: Vertex (VELO) and Trackers (IT, TT), RICH2, Calorimeters, Muon o  Start of spatial alignment   Continue time alignment among sub-detectors



Some results from Test Pulse


  The electromagnetic and the hadronic Calorimeters time aligned ~ 1ns o  Same electronics and same cable lengths

  Each Muon half-station internally aligned ~ 3 ns o  5 stations divided into two independent sides

(A and C)   No time compensation among the two sides   No time of flight compensation between

different stations

  No relative time alignment among different sub-detectors


Some results from Test Pulse


  The electromagnetic and the hadronic Calorimeters time aligned ~ 1ns o  Same electronics and same cable lengths

  Each Muon half-station internally aligned ~ 3 ns o  5 stations divided into two independent sides

(A and C)   No time compensation among the two sides   No time of flight compensation between

different stations

  No relative time alignment among different sub-detectors

FORWARD Cosmics tracks

Firsts Cosmics 2008: Muon and Calorimeter Not time aligned ~ 20 ns

MUON

CALORIMETER Trigger by Calorimeter

t (ns)

t (ns)




WITHOUT Beam

WITH Beam




o  Cosmics cross 3 main detectors: Calorimeters, Muon and Outer Tracker (OT)   Start of the Level0 hardware trigger commissioning   Start of time alignment among different sub-detectors

3.  LHC injection test (started September 2008) o  Sub-detectors: Vertex (VELO) and Trackers (IT, TT), RICH2, Calorimeters, Muon o  Start of spatial alignment   Continue time alignment among sub-detectors



Commissioning with Cosmics   Challenging because of the detector geometry

Low statistic for inner regions! o  Detector acceptance and trigger optimized with respect to the interaction point o  ~ 4 M events collected


Cosmic on Calorimeters display

2008 cosmics data; No first muon station M1!

OUTER TRACKER

CALORIMETERS

MUON   Only 3 sub-detectors involved Outher Tracker,

Calorimeters and Muon

Inner tracker too small Vertex detector and Trigger

tracker too far

RICHes out of time acquisition window


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 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

Start time alignment between sub-detectors




WITHOUT Beam

WITH Beam





3.  LHC injection test (started September 2008) o  Sub-detectors: Vertex (VELO) and Trackers (IT, TT), RICH2, Calorimeters, Muon Continue time alignment among sub-detectors   Start of spatial alignment

4. Beam-gas interactions and beams collision (started autumn 2009) o  All sub-detectors Tune calibrations and firsts commissioning results


LHCb

Commissioning with Beam: TED run   TED Runs (Transfer line External beam Dump)

o  Beam2 dumped on the injection line beam stopper 350 m downstream LHCb

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

  Shots every 48 seconds o  several 103 events acquired

•  10 particles/cm2 in the center of shower •  Vertex: 0.1 particles/cm2

•  Muon ~ 70 candidates per shot

  Rough time alignment among sub-detectors ~2 ns


TED run 8/24/2008 A/C side not aligned

A side C side

Improvement for the central Muon station M3 from TED run

correction 2008 2010

TED run 2/18/2010 Few holes! Good uniformity!

A side C side

x (cm)

x (cm)

y (c

m)

y (c

m)


VELO, Trigger Tracker, Inner Tracker detectors start of spatial alignment

TED run: spatial alignment

Residual for relative Alignment VELO -Trigger Tracker (TT)

IT

TT

VELO

  Relative Alignment VELO -Trigger Tracker (TT) o  expected uncertainty VELO-TT

extrapolation: 300 μm

o  hit residual observed in TT: 500 μm o  offset: 150-300 μm

  Inner Tracker (IT) alignment ~ 15μm

BEAM2

Inner Tracker (IT)

Single TED shot [mm]


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 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




WITHOUT Beam

WITH Beam





3.  LHC injection test (started September 2008) o  Sub-detectors: Vertex (VELO) and Trackers (IT, TT), RICH2, Calorimeters, Muon   Start of spatial alignment   Continue time alignment among sub-detectors



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  ~ 80 k 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) •  open @ 15 mm beam-gas and beam-beam 2009 runs VErtex LOcator

21 stations of Silicon strip detector

FORWARD BACKWARD


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 Beam - Gas [XZ] Plane; Crossing Angle

BEAM1 BEAM2 BEAM1 BEAM2


pp collisions: calorimeter

Electromagnetic Calorimeter (ECAL) reconstructs π0 signal

o  <m> = (133 ± 3) MeV/c2 agreement with the PDG value

o  σ= (11 ± 4) MeV/c2


Beam-Beam very first data: 23 November 2009

Mγγ (MeV/c2)

Now π0 can be routinely monitored on-line

  Recorded ~ 7 μb-1 of integrated luminosity of minimum bias triggers with all sub-detectors operational  ~ 260 k pp collisions @ 450 GeV (beam-gas subtracted)  Luminosity measurement (Vladislav talk’s)


pp collisions: 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 !

  Using full tracking power, including VELO (open 15 mm)

o  Accuracy will be further improved after complete alignment

M(Λ) = 1115.6 ± 0.2 MeV/c2

σ = 3.1 ± 0.2 MeV/c2

M(Λ PDG) =1115.7 MeV/c2

M(Λ) = 1115.6 ± 0.1 MeV/c2

σ = 1.4 ± 0.1 MeV/c2

M(ΛPDG) =1115.7 MeV/c2

For Prompt V0-production in inelastic pp-collisions see Mathias talk’s


pp collisions: 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 RICHes o  orange points: photon hits o  Continuous lines: expected distribution for

each particle hypothesis

With RICHes

PID!


pp collisions: muon


Event with dimuons o  Oppositely charged muon

candidates from the interaction region

Time resolution in perfect agreement with expectation! Beam-Beam @ 450GeV pilot run 2009

[yz] [yz]

TRACKERs

CALORIMETERs

MUON TRACKERs

CALORIMETERs

MUON


Conclusions


  LHCb detector is in good shape!   Cosmics data and the initial LHC accelerator operation have been

very useful for the commissioning of LHCb detector   Beam‐induced events and the first collisions were used to conclude

commissioning; high statistics will be 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  Bs µ µ ; φs from Bs J/ψ φ o  CP violation in Bsφγ o  mixing measurements in the D sector o  search for CPV and rare decays (D0->µµ) in the charm sector o  And more…

730 members 15 countries 54 institutes

LHCb collaboration

•  For Prompt V0-production in inelastic pp-collisions see Mathias talk’s •  For Luminosity measurement see Vladislav talk’s


Thanks!


730 members 15 countries 54 institutes

LHCb collaboration

25


Backup



M(KS) = 497.3 ± 0.2 MeV/c2

σ = 4.3 ± 0.1 MeV/c2

M(KS PDG) =497.7 MeV/c2

pp collision: tracking Ks


M(KS) = 496.9 ± 0.3 MeV/c2

σ = 11.0 ± 0.4 MeV/c2

M(KS PDG) =497.7 MeV/c2

  Using full tracking power, including VELO (open 15 mm)

o  Accuracy will be further improved after complete alignment

  The masses of the reconstructed KS in agreement with the PDG values   Tracking without VELO: tracking detectors were well calibrated at the start-up !

For Prompt V0-production in inelastic pp-collisions see Mathias talk’s


High Level Trigger Farm

Data Acquisition Boards

ONLINE and OFFLINE data Monitoring and Processing

Injector

FEST

data fl

ow

LHCb detector data flow

DAQ network

Commissioning of DAQ chain

  Commissioning of: o  run control

•  run HLT; •  exercise control/configuration

o  HLT processing o  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-MonteCarlo events injected into the DAQ chain

o  inject @ 2kHz at the High Level Trigger input (limited by MonteCarlo injection) o  generated 100 M minimum bias (14 hours)


Detector and Run Control Run the LHCb detector as a whole from

one console o  All sub-detectors included and operational o  Detector readout with a random trigger at

1 MHz o  Data storage at 2 kHz


LHCb PVSS Global Console

LHCb Control Room

Detector operated with a unified control software o  PVSS to control HW and SW processes

Documents

C. Deplano#+#On#behalf#of#the#LHCb#Collabora4on# LHCb ...moriond.in2p3.fr/QCD/2010/SundayMorning/Deplano.pdf · (VELO) Tracker (IT,OT) Calorimeters (ECAL, HCAL) Muon RICH2 RICH1 p