The LHCf detectors: zero degree calorimeters at LHC for cosmic ray physics Tsuyoshi Mase for the...

The LHCf detectors: zero degree calorimeters at LHC for cosmic ray physics

Tsuyoshi Mase

for the LHCf collaboration

Solar-Terrestrial Environment Laboratory,

Nagoya University

12 Mar. 2009 TIPP09 T.Mase 2

Outline

Motivation of the LHCf experimentHigh energy cosmic ray problem

hadron interaction model

LHCf detectorLocation

Discrimination the hadron interaction models

Design

Performance (SPS beam test and simulation)

Conclusion


Energy spectrum of cosmic rays

Engel, Nuclear Phys. B (Proc. Suppl.) 151 (2006) 437-461

Knee; acceleration limit of galactic CRs?

GZK cutoff; Propagation limit due to CMB


Cosmic ray composition by Auger

Xmax favors heavy primary

Anisotropy favors light primary (if accept AGN correlation)

interpretation strongly depends on the hadron interaction model

Confirmation of the various models using the LHC is important key for the cosmic ray physics.


LHC accelerator

The 14TeV center of momentum energy of the LHC will push the laboratory equivalent collision energy up to 10^17eV.

ATLAS / LHCfLHCb

CMS / TOTEM

ALICE


The LHCf collaborator

K.Fukui, Y.Itow, T.Mase, K.Masuda, Y.Matsubara, H.Menjo, T.Sako, K.Taki

Solar-Terrestrial Environment Laboratory, Nagoya University, JapanK.Yoshida Shibaura Institute of Technology, JapanK.Kasahara, M.Mizuishi, S.Torii

Waseda University, JapanT.Tamura Kanagawa University, JapanY.Muraki Konan UniversityY.Shimizu ICRC, University of Tokyo, JapanM.Haguenauer Ecole Polytechnique, FranceW.C.Turner LBNL, Berkeley, USAO.Adriani, L.Bonechi, M.Bongi, R.D’Alessandro, M.Grandi, P.Papini, S.Ricciarini, G.Castellini, A. Viciani

INFN, Univ. di Firenze, ItalyA.Tricomi INFN, Univ. di Catania, Italy J.Velasco, A.Faus IFIC, Centro Mixto CSIC-UVEG, SpainD.Macina, A-L.Perrot CERN, Switzerland


Location of LHCf

140mLHCfDetectors installed in the TAN region, 140m away from the Interaction Point.

Both side of I.P. (Arm1 and Arm2)

LHCf covers pseudo-rapidity > 8.4

I.P.

90cm

140m

Arm1 Arm2

neutral particle absorber


Model dependence in LHCf

Model Discrimination by Gamma, Neutron and 0

Gamma Spectrum

expected spectra using some hadron interaction models


LHCf Detector1 (Arm1)

16 scintillator layers (3 mm thick)

Trigger and energy profile measurements

Absorber

22 tungsten layers 7mm – 14 mm thick

(W: X0 = 3.5mm, RM = 9mm)

4 pairs of scintillating fiber layers for tracking purpose (6, 10, 32, 38 r.l.)

Energy

Impact pointImpact point

2 towers 24 cm long stacked vertically with 5 mm gap

Lower: 2 cm x 2 cm area

Upper: 4 cm x 4 cm area

44 radiation length

1.7 interaction length


LHCf Detector2 (Arm2)

4 pairs of silicon microstrip layers (6, 12, 30, 42 r.l.) for tracking purpose (X and Y directions)

We used LHC styleelectronics and readout

16 scintillator layers (3 mm thick)

Trigger and energy profile measurements

Absorber22 tungsten layers 7mm – 14 mm thick (2-4 r.l.)

(W: X0 = 3.5mm, RM = 9mm)

2 towers 24 cm long stacked on their edges and offset from one another

Lower: 2.5 cm x 2.5 cm

Upper: 3.2 cm x 3.2 cm

Energy

Impact point


Double arm detectors

Arm#2 DetectorArm#2 DetectorArm#1 DetectorArm#1 Detector 90mm90mm290mm290mm


Compact calorimeter and shower leakage correction

Compact two tower calorimeterneed for science

fit the limit of TAN

avoid multi-hit

reconstruct 0 invariant massThe 0 mass can be reconstructed in the invariant mass distribution of two gamma -rays, one each hitting the two tower calorimeters of Arm1 or Arm2.

Shower leakage occursThe fraction of shower leakage is only a function of the position and independent of the energy


SPS beam test

2007 Aug. 24 - Sep.11

Aim for SPS beam test

　 Calibration the performanceEnergy Calibration

Energy Resolution

Position Resolution

particle ID

Silicon Tracker

LHCf Detector

Beam Pipe

electron 50, 100, 150, 180, 200GeV/c

muon 150GeV/c

proton 150, 350GeV/c

ADAMO (silicon tracker)

LHCf Detector

Trigger scintillator


Energy Resolution

SPS beam test resultand simulation

Simulation at the LHC condition

L.G. = Low PMT Gain

H.G. = High PMT Gain

Summing up the signal in all the layers, the energy resolution is defined as root-mean-square of the distribution.


Position Resolution (SciFi : Arm1)200 GeV electrons

SPS beam test result

Simulation at the LHC condition

The center determined by the SciFi is compared with the incident particle position estimated by ADAMO.


Position Resolution (Silicon : Arm2)

200 GeV electrons

SPS beam test result

• 64mm x 64mm total surface area

• 285m thick n-type wafer

• A sequence of 768 p+ microstrips with 80mm pitch

This analysis was done using ADAMO for the reconstruction of the trajectory of each particle hitting the calorimeter.


0 reconstruction (1)

9.15 m

gamma350 GeV Proton beam

Carbon target (3 cm)in the slot used for beam monitor Arm1

Not in scale!

EEgammagamma=18GeV=18GeV

Shower Profile @ First SciFi Layer Shower Profile @ First SciFi Layer Calorimeters Calorimeters

20mm20mm

XX

40mm40mm

XX YY

YYEEgammagamma=46GeV=46GeV


0 reconstruction (2)

250 0 events triggered (in a quite big background)The background is caused by uncorrelated pairs those accidentally hit the two

calorimeters simultaneously. The background distribution was evaluated by shifting the events in the two c

alorimeters so that any correlated pairs disappear.


Radiation test

The LHCf detectors will be exposed to a considerable amount of ionizing radiation

Using 290MeV/n Carbon beam and 100TBq 60Co gamma ray

100Gy


LHCf Operation

LHCf operationLuminosity < 1030 cm-2 s-1

107 inelastic collision

3 days operation

The decrease of the light output is not large for doses of interest for LHCf

The laser calibration system can correct

The manipulators move the detectors to the safe position

100Gy


Conclusion

LHCf will set a crucial calibration point at 1017eV for the hadron interaction models

The LHCf detectors are sampling and imaging calorimeterslocate both side of the IP1 (Arm1 and Arm2)

made of plastic scintillators interleaved with tungsten converters

correct the shower leakage from the calorimeter

Performance was evaluated by SPS and simulationenergy resolution is 5% above 100GeV gamma-ray

position resolution is 150um@Arm1, 50um@Arm2

reconstruct 0 mass

Radiation damage is negligible

end...

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