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LHCf: a LHC Detector for Astroparticle Physics

EDS07 - 12th International Conference on Elastic and Diffractive Scattering - Forward Physics and QCD Hamburg 21 – 25 May, 2007. LHCf: a LHC Detector for Astroparticle Physics. Alessia Tricomi University and INFN Catania on behalf of the LHCf Collaboration. The LHCf Collaboration. CERN

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LHCf: a LHC Detector for Astroparticle Physics

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  1. EDS07 - 12th International Conference on Elastic and Diffractive Scattering - Forward Physics and QCD Hamburg 21 – 25 May, 2007 LHCf: a LHC Detector for Astroparticle Physics Alessia Tricomi University and INFN Catania on behalf of the LHCf Collaboration

  2. The LHCf Collaboration CERN D.Macina, A.L. Perrot USA LBNL Berkeley: W. Turner FRANCE Ecole Politechnique Paris: M. Haguenauer SPAIN IFIC Valencia: A.Fauss, J.Velasco JAPAN: STE Laboratory Nagoya University: Y.Itow, T.Mase, K.Masuda,Y.Matsubara, H.Matsumoto,H.Menjo,T.Sako,H. Watanabe Waseda University: K. Kasahara, Y.Shimizu, S.Torii Konan University: Y.Muraki Kanagawa University Yokohama: T.Tamura ITALY Firenze University and INFN: O.Adriani,, L.Bonechi, M.Bongi, G.Castellini, R.D’Alessandro, P.Papini Catania University and INFN: A.Tricomi The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  3. Outline • Introduction • Main problems in HECR physics: GZK cut off, chemical composition • Idea of LHCf • Measurement of neutral particles emitted into very forward at LHC • Simulation and test beam results • Calibration of MC code • Conclusions, plans and schedule • Toward the LHC operation The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  4. Introduction: GZK cut off GZK cutoff: 1020 eV super GZK events?!? Huge experiment (Auger, TA) will solve the statistics, but not for interaction model. 29th ICRC Pune (India) AGASA reports 18% systematic uncertainty in energy determination. 10% of systematic is due to interaction model. Accelerator calibration is necessary. HOWEVER Different interaction models give different answers for the primary cosmic ray energy estimate. 20% correction on the absolute energy scale!!! The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  5. Introduction: cosmic ray composition PROTON IRON Xmax(g/cm2) Not only GZK… Different interaction models lead different conclusions about the composition of the primary cosmic rays. Energy (eV) Knapp et al., 2003 The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  6. Development of atmospheric showers LHC Simulation of an atmospheric shower due to a 1019 eV proton. • Calibration of the models at high energy is mandatory • The dominant contribution to the energy flux is in the very forward region (  0) • In this forward region the highest energy available measurements of p0 cross section were done by UA7 (E=1014 eV, y= 5÷7) We propose to use LHC, the highest energy accelerator 14 TeV in the center of mass Elab=1017 eV(Elab= E2cm/2 mP) Major LHC detectors (ATLAS, CMS, LHCB) will measure the particles emitted in the central region LHCf is a tool to calibrate MC code to energy relevant for CR physics. It will cover the very forward part May be also Heavy Ion runs???? The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  7. The LHC ring 27 km ring IP1 ATLAS The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  8. LHCf: location and experimental layout Detector I Tungsten Scintillator Scintillating fibers Detector II Tungsten Scintillator Silicon mstrips INTERACTION POINT IP1 (ATLAS) 140 m 140 m Beam line Detectors should measure energy and position of g from p0 decays e.m. calorimeters with position sensitive layers • Two independent detectors on both side of IP1 • Redundancy • Background rejection (especially beam-gas) The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  9. LHCf location Detectors will be installed in the TAN region, 140 m away from the Interaction Point, in front of luminosity monitors • Here the beam pipe splits in 2 separate tubes. • Charged particle are swept away by magnets!!! • We will cover up to y The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  10. Detector #1 Impact point (h) 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 4 pairs of scintillating fiber layers for tracking purpose (6, 10, 32, 38 r.l.) Absorber 22 tungsten layers 7mm – 14 mm thick (W: X0 = 3.5mm, RM = 9mm) 16 scintillator layers (3 mm thick) Trigger and energy profile measurements Energy The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  11. Arm1 was fully assembled in Japan in July 2006 (scintillators + fibers + Tungsten) and fully tested at CERN in August 2006 beam test Arm 1 The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  12. Detector # 2 We used LHC style electronics and readout Impact point(h) 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 4 pairs of silicon microstrip layers (6, 12, 30, 42 r.l.) for tracking purpose (X and Y directions) 16 scintillator layers (3 mm thick) Trigger and energy profile measurements Absorber 22 tungsten layers 7mm – 14 mm thick (2-4 r.l.) (W: X0 = 3.5mm, RM = 9mm) Energy The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  13. Arm2 was partially assembled in Florence in July 2006 and brought to CERN for the Beam Test of August 2006 Arm2 was fully assembled in Florence in April 2007 Arm 2 The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  14. LHCf Physics performance • Single photon spectrum • p0 fully reconstructed (1 g in each tower) p0 reconstruction is an important tool for energy calibration (p0 mass constraint) Basic detector requirements: • minimum 2 towers (p0 reconstruction) • Smallest tower on the beam (multiple hits) • Dimension of the tower  Moliere radius • Maximum acceptance (given the LHC constraints) Simulation Beam Test The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  15. LHCf performances: acceptance on PTg-Eg plane 140 Beam crossing angle Detectable events A vertical beam crossing angle > 0 will increase the acceptance of LHCf The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  16. LHCf performances: single g geometrical acceptance Some runs with LHCf vertically shifted few cm will allow to cover the whole kinematical range The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  17. LHCf performances: g shower in Arm #2 500 GeV g shower Position resolution of detector # 2 Fluka based simulation 7 mm for 1.8 TeV g The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  18. LHCf performances: p0 mass resolution Arm #1 DE/E=5% 200 mm spatial resolution Dm/m = 5% The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  19. LHCf performances: Monte Carlo g-ray energy spectrum (5% Energy resolution is taken into account) 106 generated LHC interactions  1 Minute exposure@1029 cm-2s-1 luminosity Discrimination between various models is feasible Quantitative discrimination with the help of a properly defined c2 discriminating variable based on the spectrum shape (see TDR for details) The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  20. LHCf performances: model dependence of neutron energy distribution Original n energy 30% energy resolution The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  21. Performances of the LHCf Detector Energy Resolution SciFi Position Resolution Measured at the SPS Beam Test in 2004 If the center of the neutral flux hits LHCf  << 1 mm resolution LHCf can measure (and provide to LHC) the center of neutral flux from the collisions The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  22. Now the real installation in LHC… The idea is that installation takes place in 2 steps: Pre-installation Final installation In between the 2 installation the baking out of the beam pipe will be done (200 oC), so the detectors should be removed Pre-Installation dates have been fixed in Fall 2006 • LSS1L (Arm1) • 8/01/2007 to 26/01/2007  FINISHED! • LSS1R (Arm2) • 23/04/2007 to 11/05/2007  FINISHED! Final installation dates are still under discussion The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  23. LHCf – Installation The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  24. Transport and insertion in the TAN The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

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

  26. LHCf possible running scenario • Phase-I • Parasite running during the early stage of LHC commissioning (end of 2007 – beginning of 2008) • Remove LHCf when luminosity reaches 1030 cm-2s-1 for radiation reason • Phase-II • Re-install the detector at the next opportunity of low luminosity run • Phase-III • Future extension for p-A, A-A run with upgraded detectors??? The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  27. LHCf: conclusions and plans • LHCf approved in June 2006 by the LHCC • Physics performances: • able to measure π0 mass with ±5% resolution. • able to distinguish the models by measurements of π0 and γ • able to distinguish the models by measurements of n • Beam crossing angle ≠0 and/or vertical shifts of LHCf by few cm will allow more complete physics measurements • Detectors: • ARM1 and ARM2 fully ready • Performance measured in Test Beams • Installation well advanced • ARM1 successfully pre-installed in January 07 • ARM2 successfully pre-installed in April-May 07 • Final installation date under discussion • Running conditions: • Three foreseen phases • Phase I: low luminosity run during LHC commissioning • Phase II: low luminosity runs and possibly LHCf dedicated runs • Phase III: Heavy Ion runs ? Waiting for LHC beams!!! The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  28. Back-up slides The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  29. The TAN and LHCf box ~ (15×15×40) cm3 manipulator marble shielding boxes for DAQ electronic The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  30. Transverse projection of detector #1 in the TAN slot The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  31. Transverse projection of detector #2 in the TAN slot The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  32. Lateral view of ARM #2 Front scintillator Front scintillator: Fixed position wrt to TAN Silicon + Tungsten + Scintillator: +/- 5 cm vertical excursion Si Tracker + Hybrid PMTR7400 Beam axis The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  33. g rate The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  34. p0 rate The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  35. g ray energy spectrum for different positions QGSJETII: used model QGSJET: c2/DOF=107/125 DPMJET3: c2/DOF=224/125 SYBILL: c2/DOF=816/125 The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  36. The CERN test beam on August 2004 e, m, p beam Silicon Calorimeter Before correction After correction 2 mm The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  37. Leak Correction Monte Carlo N Particles MC predicts that the leakage is energy independent! Distance from Edge Prototype Experiment correction The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  38. beam-beam pipe  E γ(signal) > 200 GeV, OK background < 1% beam-gas  It depends on the beam condition background < 1% (under 10-10 Torr) beam halo-beam pipe  It has been newly estimated from the beam loss rate Background < 10% (conservative value) Estimate of the background The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  39. SPS Beam Test LHCf Detector Silicon Tracker Moving Table • Test was successful • Analysis is under way for • Energy calibration of the calorimeters • Spatial resolution of the tracking systems • CERN : SPS T2 H4 • 2006 Aug. 28 – Sep. 4 • Incident Particles • Proton150,350GeV/c • Electron 100,200GeV/c • Muon 150GeV/c Setup Trigger Scintillator The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  40. The effect of LHCf on BRAN measurements has been studied in the last months by simulation Reduction of shower particles at BRAN Position dependence on beam displacement (question from machine peoples: if we shift by 1 mm the real beam, does the center of the measured neutral energy shifts by 1 mm?) Effect of LHCf on BRAN measurement LUMI monitor (BRAN) inside TAN is beyond LHCf (replacing 4th copper bar) IP1 Cu Bar / ZDC Cu Bar / ZDC LHCf LHCf Lumi Lumi The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  41. BRAN response vs beam position If the position of beam center stays within a few mm from the beam-pipe center, the reduction factors do not change more than 10% 1 x 1 cm2 1 x 1 cm2 Relative change of the reduction factors for BRAN with respect to the nominal value (center of the beam: nominal one) Arm #1 Arm #2 The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007 H.Menjo

  42. LHCf performances: p0 geometrical acceptance Arm #1 Arm #2 The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  43. LHCf performances: energy spectrum of p0 Typical energy resolution of gis 3 % at 1TeV The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  44. Optimal LHCf run conditions • Beam parameters used for commissioning are good for LHCf!!! ( No radiation problem for 10kGy by a “year” operation with this luminosity ) The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  45. Optimal conditions for LHCf running! From R. Bailey presentation at January 2007 TAN workshop Stage 1 The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

  46. From R. Bailey presentation at January 2007 TAN workshop The LHCf experiment at LHC EDS07, Hamburg 21-25 May 2007

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