Electromagnetic calorimeter
upgrade for the di-jet
measurement in LHC-ALICE

Tatsuya Chujo
University of Tsukuba(for the ALICE Collaboration)

JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

Outline	
1. Introduc/on	  (Physics	  mo/va/on)	  2. Detector	  design	  3. Assembly	  procedure,	  status	  4. Detector	  performance	  – PS/SPS	  beam	  test	  (2010)	  – LHC10/LHC11	  data	  5. Summary	  &	  Plan	  JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

21.	  Introduc/on	
• Primary Goal: To study andcharacterize the properties ofhot, dense, deconfined matter(QGP) as produced in heavy ion
collisions at LHC.
• Energy loss of parton (ΔE) inhot and dense medium.
Powerful probe: d-jets– Importance of measurement of jetaxis, and medium response by lostparton energy.
– Large acceptance EMCal to detect
di-jet, with soft particle (<2 GeV/c)
and PID.
di-jet (quenched) event in
Pb+Pb √sNN = 2.76 TeV (CMS)JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

32. ALICE and DCal
EMCal
Lead-Scintillator
Sampling CalorimeterΔη = 1.4, Δφ =100o
APD Photosensor
11520 Towers

PHOS	  TPC

PWO	  crystal	  EMC.	  
220°	  <	  φ	  <	  320°,	  Δη	  =	  0.24	  Energy	  resolu/on	  ~3%//√E	

γ trigger.	  

Charged	  par/cles	  Δη	  =	  1.8.	  
Excellent	  momentum	  resoluBon.	  
Excellent	  PID	  and	  heavy	  ﬂavor	  tagging.	  

JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

4ALICE	  Dijet	  Calorimeter	  (DCal)	
•Extension of the acceptance of EMCal .

•Lead-scintillator sampling type EMC
with APD readout.
– EMCal: Δφ = 110°
– DCal: Δφ = 60° (on opposite side ofEMCalà good uniformity, less sys.
uncertainty)– Δη = 0.7 for both EMCal and DCal +PHOS– Energy resolution: ~10%/√E
•DCal
PHOS

Allow back-to-back hadron-jet, di-jet
measurements in ALICE, with R = 0.4 jetcone radius, up to pT ~ 150 GeV/c.

•Enhance jet, γ trigger capability.

JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)•Full energy scale for γ: 250 GeV.

5

DCal	  components	

JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

6DCal Readout

Preamplifier+APD

•
•
•••
•

4 6x6 cm2 towers/module
WLS fiber readout on 1cm grid
5x5 mm2 Hamamatsu and Perkin Elmer APDs
~4.5 photo-electrons/MeV at gain M=1
Operated at nominal gain M=30
Full scale Energy = 250 GeV
JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

7

Pressure (kg)Pressure (kg)station with pressure
3.	  Assembly	  procedure	 Press
monitoring system

JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

Time (for 1st 24 hr.)Time (for 2nd 24 hr.)

8Module check before shipping(Feb. 2011, Tsukuba)

Shipping prep. completed(Jul. 2011, Tsukuba)

Shipped to Nantes, France9(Jul. 2011, Tsukuba)

JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)SM	  assembly,	  APD	  gain	  calibra/on	  @	  LPSC	  Grenoble,	  France	SM assembly(Aug. 2011, Grenoble)

APD Gain dispersion
w/ cosmic ray (MIP):~ 2% for 384 ch.
APD gain (ch)JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

10EMCal/DCal	  PS	  Beam	  Conﬁg.	  

• PS beam period in T10 beamline August 2-16, 2010
– 0.5 GeV/c - 6 GeV/c

BeamFeµ-tag

Cherenkov

EMCAL
MWPCs (Grenoble)[8x8 towers,Eq. to SMA0RCU0]

Beam
Scintillators(Tsukuba~60ps)

January 27, 2011�JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

Beam Test, T.Awes

1111

EMCal/DCal	  SPS	  Beam	  Conﬁg.	  
• SPS beam period in H4 beamline August 23-30, 2010
– 6 GeV/c - 250 GeV/c e and h~25 m

Beam

EMCAL
MWPCs (Grenoble)
8x8 towers,
Eq. to SMA0RCU0Beam
Scintillators(Tsukuba)

January 27, 2011

�JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

Beam Test, T.Awes

1212

4. Detector Performance! 10.5%=!1.9%
EE
5.3!x =!1.5mmE• PS	  beam	  period	  in	  T10	  beamline	  August	  2-­‐16,	  2010	  – 0.5	  GeV/c	  -­‐	  6	  GeV/c	  • SPS	  beam	  period	  in	  T2-­‐H4	  beam	  for	  7	  days	  August	  23-­‐30,	  2010	  – 	  6	  GeV/c	  -­‐	  250GeV/c	  JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

13Invariant mass for π0 in p+p 7.0 TeV p+pand "Pb+Pb 2.76 TeV Pb+Pb

p+p

10% most central Pb+Pb
dNch/dη ~1600
JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

14Jet Measurements in 2.76 TeV Pb+Pb (LHC11)

L1 jet trigger

Jet energy with
EMCal + TPC
tracking• For	  2011	  run,	  all	  of	  EMCal	  is	  installed	  and	  trigger	  was	  in	  use.	  
JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

155.	  Summary	  and	  plan	• DCal in ALICE provides a powerful tool toinvestigate QGP through dijet and photon.
• All module production for DCal has been
completed (1,344 modules).
• SM assembly is on going at Grenoble, France.
• DCal will be installed in ALICE during the LHC
long shutdown (2012-2014), will be ready totake full energy 5.5 TeV Pb+Pb run.
• Detector performance for jet and gamma ispromising.
JPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)

16

ALICE-DCal Collaboration
China
Huazhong Normal University (CCNU), Wuhan
Finland
University of Jyvaskyla
FranceLPSC Grenoble, Subatech Nantes, IPHC Strasbourg
Italy
INFN Catania, LNF Frascati,Japan
Hiroshima University, University of Tokyo, University of Tsukuba,
Switzerland
CERN
USA
Lawrence Berkeley National Laboratory, Wayne State University, University ofHouston, University of Tennessee, Lawrence Livermore National Laboratory,
Yale University, Oak Ridge National Laboratory, Creighton University, Cal Poly
17San Luis Obispo, PurdueUniversityJPS 2012 spring meeting, Kwansei Gakuin Univ., March 26, 2012 (T. Chujo)