Alessia Tricomi University and INFN Catania on behalf of the LHCf Collaboration LHCf: a LHC Detector for Astroparticle Physics EDS07 - 12th International

Alessia TricomiAlessia TricomiUniversity and INFN CataniaUniversity and INFN Catania

on behalf of the LHCf on behalf of the LHCf CollaborationCollaboration

LHCf: a LHC Detector for LHCf: a LHC Detector for Astroparticle PhysicsAstroparticle Physics

EDS07 - 12th International Conference on EDS07 - 12th International Conference on Elastic and Diffractive Scattering - Elastic and Diffractive Scattering -

Forward Physics and QCDForward Physics and QCDHamburg 21 – 25 May, 2007Hamburg 21 – 25 May, 2007

Alessia Tricomi UniAlessia Tricomi University & INFN Cataversity & INFN Cataniania

The LHCf experiment at LHC The LHCf experiment at LHC EDS07, Hamburg 21-25 EDS07, Hamburg 21-25 May 2007 May 2007

The LHCf CollaborationThe LHCf Collaboration

ITALYITALYFirenze University and INFN:Firenze University and INFN: O.Adriani,, L.Bonechi, O.Adriani,, L.Bonechi, M.Bongi, G.Castellini, M.Bongi, G.Castellini, R.D’Alessandro, P.PapiniR.D’Alessandro, P.PapiniCatania University and Catania University and INFN:INFN: A.Tricomi A.Tricomi

JAPAN:JAPAN:STE Laboratory Nagoya University:STE Laboratory Nagoya University:Y.Itow, T.Mase, Y.Itow, T.Mase, K.Masuda,Y.Matsubara, K.Masuda,Y.Matsubara, H.Matsumoto,H.Menjo,T.Sako,H. H.Matsumoto,H.Menjo,T.Sako,H. WatanabeWatanabeWaseda University:Waseda University: K. Kasahara, K. Kasahara, Y.Shimizu, S.ToriiY.Shimizu, S.ToriiKonan University:Konan University: Y.Muraki Y.MurakiKanagawa University Yokohama: Kanagawa University Yokohama: T.TamuraT.Tamura

SPAINSPAINIFIC Valencia:IFIC Valencia: A.Fauss, A.Fauss, J.VelascoJ.Velasco

FRANCEFRANCEEcole Politechnique Paris:Ecole Politechnique Paris:M. HaguenauerM. Haguenauer

USAUSALBNL Berkeley:LBNL Berkeley:W. TurnerW. Turner

CERNCERND.Macina, A.L. PerrotD.Macina, A.L. Perrot



OutlineOutlineIntroductionIntroduction

– Main problems in HECR physics: GZK cut Main problems in HECR physics: GZK cut off, chemical compositionoff, chemical composition

Idea of LHCfIdea of LHCf– Measurement of neutral particles Measurement of neutral particles

emitted into very forward at LHCemitted into very forward at LHCSimulation and test beam resultsSimulation and test beam results

– Calibration of MC code Calibration of MC code Conclusions, plans and scheduleConclusions, plans and schedule

– Toward the LHC operationToward the LHC operation



AGASA reports 18% AGASA reports 18% systematic uncertainty in systematic uncertainty in energy determination.energy determination.

10% of systematic is due to 10% of systematic is due to interaction model.interaction model.

Accelerator calibration is Accelerator calibration is necessary.necessary.

Introduction: GZK cut offIntroduction: GZK cut off

Huge experiment (Auger, TA) will Huge experiment (Auger, TA) will solve the statistics, but not for solve the statistics, but not for interaction model.interaction model.

HOWEVERHOWEVER

Different interaction models give different answers Different interaction models give different answers forfor

the primary cosmic ray energy estimate.the primary cosmic ray energy estimate.

2929thth ICRC ICRCPune (India)Pune (India)

GZK cutoff:GZK cutoff: 10 102020 eV eV

super GZK super GZK events?!?events?!?

20% correction on 20% correction on the the

absolute energy absolute energy scale!!!scale!!!



Introduction: cosmic ray Introduction: cosmic ray compositioncomposition

Not only GZK… Not only GZK…

Different interaction models leadDifferent interaction models leaddifferent conclusions about thedifferent conclusions about thecomposition of the primary cosmic rayscomposition of the primary cosmic rays..

IRON

IRON

PROTON

PROTON

Knapp et al., 2003Knapp et al., 2003Energy (eV)Energy (eV)

XXm

ax

max (g

/(g

/cmcm

22))



Development of atmospheric Development of atmospheric showersshowers

Calibration of the models at high Calibration of the models at high energy is mandatoryenergy is mandatory The dominant contribution to the The dominant contribution to the energy flux is in the energy flux is in the very forward very forward region (region ( 0) 0) In this forward region the highest In this forward region the highest energy available measurements of energy available measurements of 00 cross section were done by UA7 cross section were done by UA7 ((E=10E=101414 eV, eV, y= 5÷7)y= 5÷7)

2θlntany

Simulation of an Simulation of an atmospheric shower atmospheric shower due to a 10due to a 101919 eV eV proton.proton.

LHCLHCWe propose to use LHC, the highest We propose to use LHC, the highest energy acceleratorenergy accelerator

14 TeV in the center of mass 14 TeV in the center of mass

EElablab=10=101717 eV eV (E(Elablab= E= E22cmcm/2 m/2 mPP))

Major LHC detectors (ATLAS, CMS, Major LHC detectors (ATLAS, CMS, LHCB) will measure the particles LHCB) will measure the particles emitted in the central regionemitted in the central regionLHCf is a tool to calibrate MC code to energy LHCf is a tool to calibrate MC code to energy

relevant relevant for CR physics. It will cover the very forward for CR physics. It will cover the very forward

partpartMay be also Heavy Ion runs????May be also Heavy Ion runs????



The LHC ringThe LHC ring

27 km ring27 km ring

ATLASATLASIP1IP1



LHCf: location and experimental LHCf: location and experimental layoutlayout

INTERACTION POINTINTERACTION POINT

IP1 (ATLAS)IP1 (ATLAS)

Beam Beam lineline

Detector IIDetector II

TungstenTungsten

ScintillatorScintillator

Silicon Silicon mstripsmstrips

Detector IDetector I

TungstenTungsten

ScintillatorScintillator

Scintillating Scintillating fibersfibers

140 m140 m 140 m140 m

Detectors should measure energy and position of Detectors should measure energy and position of from from 00 decays decays e.m. calorimeters with e.m. calorimeters with position sensitive layersposition sensitive layers

Two independent detectors on both side of IP1Two independent detectors on both side of IP1 RedundancyRedundancy Background rejection (especially beam-gas)Background rejection (especially beam-gas)



LHCf locationLHCf locationDetectors will be installed in Detectors will be installed in the TAN region, 140 m away the TAN region, 140 m away from the Interaction Point, in from the Interaction Point, in front of luminosity monitorsfront of luminosity monitors

Here the beam Here the beam pipe splits in 2 pipe splits in 2 separate tubes.separate tubes.

Charged particle Charged particle are swept away by are swept away by magnets!!!magnets!!!

We will cover up to We will cover up to yy



Detector #1Detector #1

16 scintillator 16 scintillator layers (3 mm layers (3 mm

thick)thick)

Trigger and Trigger and energy profile energy profile measurementsmeasurements

AbsorberAbsorber

22 tungsten layers 22 tungsten layers 7mm – 14 mm thick7mm – 14 mm thick

(W: X(W: X00 = 3.5mm, R = 3.5mm, RMM = = 9mm)9mm)

4 pairs of4 pairs of scintillating scintillating fiber layers fiber layers for for tracking purpose tracking purpose (6, 10, 32, 38 r.l.)(6, 10, 32, 38 r.l.)

EnergyEnergy

Impact point Impact point (())

2 towers 24 cm long 2 towers 24 cm long stacked vertically stacked vertically with 5 mm gapwith 5 mm gap

Lower: 2 cm x 2 cm Lower: 2 cm x 2 cm areaarea

Upper: 4 cm x 4 cm Upper: 4 cm x 4 cm areaarea



Arm 1Arm 1Arm1 was fully assembled in Japan in July 2006 Arm1 was fully assembled in Japan in July 2006 (scintillators + fibers + Tungsten) and fully tested (scintillators + fibers + Tungsten) and fully tested at CERN in August 2006 beam testat CERN in August 2006 beam test



Detector # 2Detector # 2

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

We used LHC styleWe used LHC styleelectronics and readoutelectronics and readout

16 scintillator 16 scintillator layers (3 mm layers (3 mm

thick)thick)

Trigger and Trigger and energy profile energy profile measurementsmeasurements

AbsorberAbsorber22 tungsten layers 22 tungsten layers 7mm – 14 mm thick (2-4 7mm – 14 mm thick (2-4 r.l.)r.l.)

(W: X(W: X00 = 3.5mm, R = 3.5mm, RMM = = 9mm)9mm)

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

Lower: 2.5 cm x 2.5 cmLower: 2.5 cm x 2.5 cm

Upper: 3.2 cm x 3.2 cmUpper: 3.2 cm x 3.2 cm

EnergyEnergy

Impact pointImpact point (())



Arm 2Arm 2o Arm2 was partially Arm2 was partially

assembled in Florence in assembled in Florence in July 2006 and brought to July 2006 and brought to CERN for the Beam Test of CERN for the Beam Test of August 2006August 2006

o Arm2 was fully assembled Arm2 was fully assembled in Florence in April 2007in Florence in April 2007



LHCf Physics performanceLHCf Physics performance

1.1. Single photon spectrumSingle photon spectrum2.2. 00 fully reconstructed (1 fully reconstructed (1 in each tower) in each tower)

00 reconstruction is an important tool for reconstruction is an important tool for energy calibration (energy calibration (00 mass constraint) mass constraint)

Basic detector requirements: Basic detector requirements: minimum 2 towers (minimum 2 towers (00 reconstruction) reconstruction) Smallest tower on the beam (multiple hits)Smallest tower on the beam (multiple hits) Dimension of the tower Dimension of the tower Moliere radius Moliere radius Maximum acceptance (given the LHC Maximum acceptance (given the LHC

constraints)constraints)

SimulationSimulation Beam TestBeam Test



Detec

table

eve

nts

Detec

table

eve

nts

140 Beam crossing Beam crossing angleangle

LHCf performances: acceptance LHCf performances: acceptance on Pon PTT-E-E plane plane

A vertical beam crossing angle > 0 will A vertical beam crossing angle > 0 will increase the acceptance of LHCfincrease the acceptance of LHCf



LHCf performances: single LHCf performances: single geometrical acceptancegeometrical acceptance

Some runs with LHCf vertically shifted few cm Some runs with LHCf vertically shifted few cm will allow to cover the whole kinematical rangewill allow to cover the whole kinematical range



LHCf performances: LHCf performances: shower in shower in Arm #2Arm #2

Fluka based simulation

7 7 m for 1.8 TeV m for 1.8 TeV

Position resolution of detector # 2Position resolution of detector # 2

500 GeV 500 GeV shower shower



Arm #1Arm #1E/E=5%E/E=5%200 200 m spatial resolutionm spatial resolution

m/m = 5%m/m = 5%

LHCf performances: LHCf performances: 00 mass mass resolutionresolution



LHCf performances: Monte Carlo LHCf performances: Monte Carlo -ray -ray energy spectrumenergy spectrum

(5% Energy resolution is taken into account) (5% Energy resolution is taken into account)

101066 generated LHC interactions generated LHC interactions 1 Minute exposure@101 Minute exposure@102929 cm cm-2-2ss-1-1 luminosity luminosity Discrimination between various Discrimination between various models models is feasibleis feasible

Quantitative Quantitative discrimination discrimination with the help with the help of a properly of a properly defined defined 22 discriminating discriminating variable variable based on the based on the spectrum spectrum shape shape (see TDR for (see TDR for details)details)



LHCf performances: LHCf performances: model dependence of neutron energy model dependence of neutron energy

distributiondistribution

Original n energyOriginal n energy 30% energy resolution30% energy resolution



SciFi Position ResolutionSciFi Position ResolutionEnergy ResolutionEnergy Resolution

Measured at the SPS Measured at the SPS

Beam Test in 2004Beam Test in 2004

LHCf can measure (and LHCf can measure (and provide to LHC) the center of provide to LHC) the center of neutral flux from the collisions neutral flux from the collisions

If the center of the If the center of the neutral flux hits LHCf neutral flux hits LHCf << 1 mm << 1 mm resolutionresolution

Performances of the LHCf Performances of the LHCf DetectorDetector



Now the real installation in Now the real installation in LHC…LHC…

Pre-Installation dates have been fixed in Fall 2006Pre-Installation dates have been fixed in Fall 2006– LSS1L (Arm1)LSS1L (Arm1)

• 8/01/2007 to 26/01/2007 8/01/2007 to 26/01/2007 FINISHED! FINISHED!– LSS1R (Arm2)LSS1R (Arm2)

• 23/04/2007 to 11/05/2007 23/04/2007 to 11/05/2007 FINISHED! FINISHED!

Final installation dates are still under Final installation dates are still under discussiondiscussion

The idea is that installation takes place in 2 The idea is that installation takes place in 2 steps:steps:

Pre-installationPre-installationFinal installationFinal installation

In between the 2 installation the baking out of In between the 2 installation the baking out of the beam pipe will be done (200 the beam pipe will be done (200 ooC), so the C), so the detectors should be removeddetectors should be removed



LHCf – InstallationLHCf – Installation



Transport and insertion in Transport and insertion in the TANthe TAN





LHCf possible running LHCf possible running scenarioscenarioPhase-IPhase-I

– Parasite running during the early stage Parasite running during the early stage of LHC commissioning (end of 2007 – of LHC commissioning (end of 2007 – beginning of 2008)beginning of 2008)

– Remove LHCf when luminosity reaches Remove LHCf when luminosity reaches 101030 30 cmcm-2-2ss-1-1 for radiation reason for radiation reason

Phase-IIPhase-II– Re-install the detector at the next Re-install the detector at the next

opportunity of low luminosity run opportunity of low luminosity run Phase-IIIPhase-III

– Future extension for p-A, A-A run with Future extension for p-A, A-A run with upgraded detectors???upgraded detectors???



LHCf: conclusions and plansLHCf: conclusions and plans LHCf approved in June 2006 by the LHCCLHCf approved in June 2006 by the LHCC Physics performances: Physics performances:

– able to measure πable to measure π00 mass with ±5% resolution. mass with ±5% resolution.– able to distinguish the models by measurements of πable to distinguish the models by measurements of π00

and γand γ– able to distinguish the models by measurements of able to distinguish the models by measurements of nn– Beam crossing angle ≠0 and/or vertical shifts of LHCf by Beam crossing angle ≠0 and/or vertical shifts of LHCf by

few cm will allow more complete physics measurementsfew cm will allow more complete physics measurements Detectors:Detectors:

– ARM1 and ARM2 fully readyARM1 and ARM2 fully ready– Performance measured in Test BeamsPerformance measured in Test Beams

Installation well advancedInstallation well advanced– ARM1 successfully pre-installed in January 07ARM1 successfully pre-installed in January 07– ARM2 successfully pre-installed in April-May 07ARM2 successfully pre-installed in April-May 07– Final installation date under discussionFinal installation date under discussion

Running conditions:Running conditions:– Three foreseen phasesThree foreseen phases

• Phase I: low luminosity run during LHC commissioning Phase I: low luminosity run during LHC commissioning • Phase II: low luminosity runs and possibly LHCf dedicated Phase II: low luminosity runs and possibly LHCf dedicated

runsruns• Phase III: Heavy Ion runs ?Phase III: Heavy Ion runs ?

Waiting fo

r LHC beams!!

!

Waiting fo

r LHC beams!!

!



Back-up slidesBack-up slides



The TAN and LHCfThe TAN and LHCf

marbleshielding

manipulator

boxes for DAQ electronic

box ~ (15box ~ (15××1515××40) cm40) cm33



Transverse projection of detector #1 Transverse projection of detector #1 in the TAN slotin the TAN slot



Transverse projection of detector #2 Transverse projection of detector #2 in the TAN slotin the TAN slot



Front scintillator:Front scintillator:Fixed position wrt to TANFixed position wrt to TAN

Silicon + Tungsten + Scintillator:Silicon + Tungsten + Scintillator:+/- 5 cm vertical excursion+/- 5 cm vertical excursion

PM

TR

74

00

PM

TR

74

00

Front scintillatorFront scintillatorLateral view of ARM #2Lateral view of ARM #2

Si Tracker + HybridSi Tracker + Hybrid

Beam axisBeam axis



raterate



raterate



QGSJETII: used modelQGSJETII: used modelQGSJET: cQGSJET: c22/DOF=107/125/DOF=107/125DPMJET3: cDPMJET3: c22/DOF=224/125/DOF=224/125SYBILL: cSYBILL: c22/DOF=816/125/DOF=816/125

ray energy spectrum for different ray energy spectrum for different positionspositions



e, , p beam

Silicon Calorimeter

Before correction After correction

2 mm

The CERN test beam on August The CERN test beam on August 20042004



Leak CorrectionLeak CorrectionMonte Carlo

Prototype Experiment

MC predicts that the leakage is energy independent!

correction

Distance from Edge

N P

arti

cles



Estimate of the backgroundEstimate of the background

beam-beam pipebeam-beam pipe E E γγ(signal) > 200 GeV, OK(signal) > 200 GeV, OK

background background < 1% < 1%

beam-gasbeam-gas It depends on the beam conditionIt depends on the beam condition

background background < 1% (< 1% (under 10under 10-10-10 Torr) Torr) beam halo-beam pipebeam halo-beam pipe It has been newly estimated from the beam loss rateIt has been newly estimated from the beam loss rate

Background Background < 10%< 10% (conservative value) (conservative value)



SPS Beam TestSPS Beam Test

LHCf LHCf DetectorDetector

SiliconSilicon TrackerTracker

Moving TableMoving TableTrigger Trigger ScintillatorScintillator

CERN : SPS T2 H4CERN : SPS T2 H4 2006 Aug. 28 – Sep. 42006 Aug. 28 – Sep. 4 Incident ParticlesIncident Particles

–ProtonProton 　　 150,350GeV/c150,350GeV/c–Electron 100,200GeV/cElectron 100,200GeV/c–Muon 150GeV/cMuon 150GeV/c

SetupSetup

Test was successfulTest was successfulAnalysis is under way forAnalysis is under way for

Energy calibration of Energy calibration of the calorimetersthe calorimetersSpatial resolution of Spatial resolution of

the tracking systemsthe tracking systems



Effect of LHCf on BRAN Effect of LHCf on BRAN measurementmeasurement

The effect of LHCf on BRAN measurements The effect of LHCf on BRAN measurements has been studied in the last months by has been studied in the last months by simulationsimulation– Reduction of shower particles at BRANReduction of shower particles at BRAN– Position dependence on beam displacementPosition dependence on beam displacement

(question from machine peoples: if we shift by (question from machine peoples: if we shift by 1 mm the real beam, does the center of the 1 mm the real beam, does the center of the measured neutral energy shifts by 1 mm?)measured neutral energy shifts by 1 mm?)

LUMI monitor (BRAN) inside TAN is beyond LHCf (replacing 4th copper bar)LUMI monitor (BRAN) inside TAN is beyond LHCf (replacing 4th copper bar)

LHCfLHCfLumiLumi

Cu Bar / ZDCCu Bar / ZDC

IP1IP1

LHCfLHCfLumiLumi

Cu Bar / ZDCCu Bar / ZDC



Arm #1 Arm #2

H.Menjo

Relative change of the reduction factors for BRAN Relative change of the reduction factors for BRAN with respect to the nominal value (center of the beam: with respect to the nominal value (center of the beam:

nominal one) nominal one)

BRAN response vs beam BRAN response vs beam positionposition

If the position of beam center stays within If the position of beam center stays within a few mm from the beam-pipe center, the a few mm from the beam-pipe center, the reduction factors do not change more than reduction factors do not change more than

10%10%

1 x 1 cm2

1 x 1 cm2



LHCf performances: LHCf performances: 00 geometrical geometrical acceptanceacceptance

Arm #1Arm #1

Arm #2Arm #2



LHCf performances: energy LHCf performances: energy spectrum of spectrum of 00

Typical energy resolution of Typical energy resolution of is 3 % at 1TeVis 3 % at 1TeV



Beam parameters Beam parameters used for used for commissioning are commissioning are good for LHCf!!!good for LHCf!!!

Beam Beam parameterparameter

ValueValue

# of bunches# of bunches ≤ ≤ 4343

Bunch Bunch separationseparation

> 2 > 2 secsec

Crossing Crossing angleangle

0 rad0 rad

140 140 rad rad downwarddownward

Luminosity Luminosity per bunchper bunch

< 2 x 10< 2 x 1028 28 cmcm-2-2ss-1-1

LuminosityLuminosity < 0.8 x 10< 0.8 x 1030 30 cmcm--

22ss-1-1

Bunch Bunch intensityintensity

4x104x101010 ppb ppb ((*=18m)*=18m)

1x101x101010 ppb ( ppb (*= *= 1m)1m)

( No radiation problem for 10kGy by a “year” operation with this luminosity )

Optimal LHCf run conditionsOptimal LHCf run conditions



From R. Bailey From R. Bailey presentation at presentation at January 2007 TAN workshop January 2007 TAN workshop

Stage 1Stage 1

Optimal conditions for LHCf running!Optimal conditions for LHCf running!



From R. Bailey From R. Bailey presentation at presentation at January 2007 TAN workshop January 2007 TAN workshop

Documents

Alessia Tricomi University and INFN Catania on behalf of the LHCf Collaboration LHCf: a LHC Detector for Astroparticle Physics EDS07 - 12th International