LHCf: un esperimento per la fisica dei raggi cosmici ad LHC Oscar Adriani Università degli Studi di Firenze INFN Sezione di Firenze

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, Y.Muraki,T.Sako,H. Watanabe Shibaura University Saitama: K.Kasahara Kanagawa University Yokohama: T.Tamura, K.Tanaka Waseda University: Y.Shimizu, S.Torii ITALY Firenze University and INFN: O.Adriani,, L.Bonechi, M.Bongi, G.Castellini, R.D’Alessandro, P.Papini Catania University and INFN: A.Tricomi Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 What is LHCf? The Detectors Oscar Adriani Perugia, 17/12/09

LHCf: an Astroparticle Experiment at LHC LHCf is the smallest of the six LHC experiments and is a fully dedicated collider experiment for HECR Physics LHCf will use the highest energy particle accelerator to provide useful data to calibrate the hadronic interaction models used in Monte Carlo simulations of atmospheric showers 7TeV+ 7 TeV proton collisions at LHC correspond to ELAB = 1017eV Two independent electromagnetic calorimeters equipped with position sensitive layers, on both sides of IP1 will measure energy and position of g from p0 decays and neutrons produced in pp interaction at LHC Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 Experimental set-up INTERACTION POINT IP1 (ATLAS) Beam line Detector II Tungsten Scintillator Silicon mstrips Detector I Scintillating fibers 140 m Detectors installed in the TAN region, 140 m away from the Interaction Point 1 Here the beam pipe splits in 2 separate tubes. Charged particle are swept away by magnets We cover up to y Charged particles Neutral particles Beam pipe Protons Oscar Adriani Perugia, 17/12/09

Arm1 2 towers 24 cm long stacked vertically with a 5 mm gap 4 pairs of scintillating fiber layers for tracking purpose (6, 10, 32, 38 X0.) Absorber 22 tungsten layers 7mm – 14 mm thick (W: X0 = 3.5mm, RM = 9mm) Arm1 16 scintillator layers (3 mm thick) Trigger and energy profile measurements 2 towers 24 cm long stacked vertically with a 5 mm gap Lower: 2 cm x 2 cm area Upper: 4 cm x 4 cm area Oscar Adriani Perugia, 17/12/09

Arm2 4 pairs of silicon microstrip layers (6, 10, 30, 42 X0) for tracking purpose (X and Y directions) 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 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 Oscar Adriani Perugia, 17/12/09

Transverse projection in TAN slot ARM1: Maximization of the acceptance for vertical beam displacement (crossing angle>0) ARM2: Maximization of the acceptance in R (distance from beam center) Oscar Adriani Perugia, 17/12/09

The mechanics of the module 25 mm Light Guides + Scintillators Hybrid circuit Pace Chips Silicon sensor Kapton fanout Tungsten SiliconX SiliconY Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 Silicon mstrips readout Pace3 chips (many thanks to CMS preshower!!!!) 32 channels 25 ns peaking time High dynamic range (> 400 MIP) 192x32 analog pipeline Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 Double ARM Detectors Arm#1 Detector Arm#2 Detector 290mm 90mm Oscar Adriani Perugia, 17/12/09

LHCf detectors in the LHC tunnel Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 Why LHCf? Physics Motivations Oscar Adriani Perugia, 17/12/09

Ultra High Energy Cosmic Rays Experimental observations: at E>100 TeV only EAS (shower of secondary particles) lateral distribution longitudinal distribution particle type arrival direction Extensive Air Showers Air shower development (particle interaction in the atmosphere) Astrophysical parameters: (primary particles) spectrum composition source distribution origin and propagation Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 The Cosmic Ray Spectra GZK cutoff: 1020eV GZK cutoff would limit energy to 1020eV for protons, due to Cosmic Microwave Background pg(2.7K)DNp super GZK events?!? Different results between different experiments Based on data presented at the 30th ICRC Merida (Mexico) Figure prepared by Y. Tokanatsu Oscar Adriani Perugia, 17/12/09

Difference in the energy scale between different experiments??? The Cosmic Ray Spectra AGASA x 0.9 HiResx 1.2 Yakutsk x 0.75 Auger x 1.2 Berezinsky 2007 AGASA Systematics Total ±18% Hadron interaction (QGSJET, SIBYLL) ~10% (Takeda et al., 2003) Difference in the energy scale between different experiments??? Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 HECR composition The depth of the maximum of the shower Xmax in the atmosphere depends on energy and type of the primary particle Different hadronic interaction models give different answers about the composition of HECR IRON PROTON Unger, ECRS 2008 IRON LHC Oscar Adriani Perugia, 17/12/09

HECR composition Auger Xmax measurements favors heavier composition as the energy increases Anisotropy would favor proton primaries (AGN correlation still valid?) Oscar Adriani Perugia, 17/12/09

Modelling Cosmic Rays at LHC Nuclear Interaction Calibration with data of Monte Carlo used in Cosmic Ray Physics Astrophysical parameters - source type - source distribution - source spectrum - source composition - propagation Forward Physics - cross section - particle spectra (E, PT, q, h, XF) Oscar Adriani Perugia, 17/12/09

Development of atmospheric showers LHC Tevatron A 100 PeV fixed-target interaction with air has the cm energy of a pp collision at the LHC AUGER Cosmic ray spectrum Determination of E and mass of cosmic rays depends on description of primary UHE interaction Hadronic MC’s need tuning with data 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 done by UA7 (E=1014eV, y= 5÷7) LHCf: use LHC √s = 14 TeVElab=1017eV to calibrate MCs AlessiaTricomi University and INFN Catania Oscar Adriani Perugia, 17/12/09

How LHCf can calibrate MC? Physics Perfomances Oscar Adriani Perugia, 17/12/09

LHCf: acceptance on PTg-Eg plane 140 Beam crossing angle Detectable events A vertical beam crossing angle > 0 will increase the acceptance of LHCf EPS 09, Krakow 16-22 July 2009 Alessia Tricomi University and INFN Catania Oscar Adriani Perugia, 17/12/09

LHCf single g geometrical acceptance Some runs with LHCf vertically shifted few cm will allow to cover the whole kinematical range Oscar Adriani Perugia, 17/12/09

Energy resolution for g For 20mm For 40mm 5% 5% Oscar Adriani Perugia, 17/12/09

ARM2 Position Resolution 200 GeV electrons Number of event σy=64 mm σx=40 mm Number of event x-pos[mm] y-pos[mm] Oscar Adriani Perugia, 17/12/09

LHCf : Monte Carlo discrimination 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 5% Energy resolution Oscar Adriani Perugia, 17/12/09

LHCf: model dependence of neutron energy distribution Original n energy 30% energy resolution Oscar Adriani Perugia, 17/12/09

g and n spectra at different energies 20 min @ 1029 cm-2s-1 1 min @ 1029 cm-2s-1 1 min @ 1029 cm-2s-1 450 GeV 1 TeV 5 TeV g g g 20 min @ 1029 cm-2s-1 1 min @ 1029 cm-2s-1 1 min @ 1029 cm-2s-1 450 GeV 1 TeV 5 TeV n n n DPMJET3 QGSJET2 QGSJET1 SIBYLL No detector resolution taken into account Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 New Models PICCO EPOS Drescher, Physical Review D77, 056003 (2008) p0 Neutron Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 p0 spectra E2 E1 Gamma2 Gamma1 p0 produced at collision can be extracted by using gamma pair events Powerful tool to calibrate the energy scale and also to eliminate beam-gas BG Emin ~ 700GeV Geometrical Acceptance Peak : 134MeV Sigma: 4.9MeV Cut: 125-145MeV 10mm Lower Oscar Adriani Perugia, 17/12/09

p0 spectra and model discrimination Reconstructed spectrum in good agreement with the original π0 production spectrum (DPMJETⅢ) Systematic errors mainly due to the uncertainty of the absolute energy scale of the calorimeters. ±5% uncertainty were conservatively assumed 20 min @ 1029 cm-2s-1 Oscar Adriani Perugia, 17/12/09

p0 reconstruction at the SPS beam test g 350 GeV Proton beam Not in scale! g Carbon target (6 cm) in the slot used for beam monitor 9.15 m Arm1 >107 proton on target (special setting from the SPS people) Dedicated trigger on both towers of the calorimeter Egamma=18GeV Shower Profile @ First SciFi Layer Calorimeters 20mm X 40mm Y Egamma=46GeV Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 p0 mass reconstruction  250 p0 events triggered (in a quite big background) (MeV) Main problems: low photon energy (≥20 GeV) Direct protons in the towers Multi hits in the same tower The LHCf experiment at LHC ISVHECRI08, Paris 1-6 September 2008 Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 When LHCf? NOW!!!!!!!!!!! Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 2009 LHC Operation From End of October 2009 LHC restarted operation 450 GeV + 450 GeV  1.2 TeV + 1.2 TeV Exceptional effort and success from LHC!!! Few weeks of ‘smooth’ running allowed LHCf to collect some statistics at 450+450 GeV in stable beam conditions (Moving from garage to running position)     No stable beam at 1.2+1.2 TeV  No data at this energy for this year  Oscar Adriani Perugia, 17/12/09

Run table for 2009 (Stable beam) Number of detected showers > 6000! RUN DATE START END GAIN #L2TA Arm1 #L2TA Arm2 BUNCH 02347 06/12/2009 23:17 00:25 Normal 65 86 4x4 (3*) 02349 08/12/2009 02:17 05:49 184 239 02379 11/12/2009 02:06 02:43 102 103 5x5 (4*) 02380 06:03 323 335 02382 07:34 10:34 411 02387 18:56 21:22 196 301 5x5 (3) 02391 12/12/2009 04:03 06:18 157 244 4x5? (2) 02393 09:33 13:00 321 447 02395 14:21 15:17 146 208 02396 15:20 18:24 337 472 02399 20:42 22:21 310 444 02412 15/12/2009 01:09 01:59 330 365 17x17? (9+3*) Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 Arm1 g event Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 Arm2 g event Oscar Adriani Perugia, 17/12/09

Arm2 neutron event Transition curve in the calorimetric towers is used to discriminate between g and n L90%<20 X0 Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 PID Photons Neutrons Oscar Adriani Perugia, 17/12/09

Very preliminary first plots! Arm1 The Beam Pipe profile is clearly seen Difference between Bunch Crossing and single bunch clearly demonstrate the evidence for collisions Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 Arm2 --D: l’ombra e’ limitata alla parte in alto a destra (molto meno importante che per Arm1) Oscar Adriani Perugia, 17/12/09

Which is the future of LHCf? Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 Plans for the future At beginning of 2010, when LHC will restart, we will take data 1.2+1.2 TeV 3.5+3.5 TeV When luminosity will become too high (>1031 cm-2s-1, 2 pb-1) we will go out from the TAN (Radiation damage of the plastic scintillator is significant, LHCf has been designed to run at low luminosity/high energy!) Oscar Adriani Perugia, 17/12/09

Radiation Damage Studies Scintillating fibers and scintillators Expected dose: 100 Gy/day at 1030 cm-2s-1 Fewmonths @ 1030 cm-2s-1: 10 kGy 50% light output Continous monitor and calibrationwith Laser system!!! The LHCf experiment at LHC ISVHECRI08, Paris 1-6 September 2008 1 kGy Alessia Tricomi University & INFN Catania 30 kGy Oscar Adriani Perugia, 17/12/09

Results on radiation damage The dose approximately scale as E3 Energy (TeV) Dose rate (Gy/hour at 1029cm-2s-1) Dose rate (Gy/nb-1) Time to reach 1KGy at 1029cm-2s-1 (days) Integrated lumi to reach 1KGy (nb-1) 0.45+0.45 4.6•10-4 1.27•10-3 9140 7.9•105 3+3 1.3•10-1 0.35 330 2.9•103 5+5 6.1•10-1 1.7 68 590 7+7 1.6 4.3 27 230 Oscar Adriani Perugia, 17/12/09

Energy flux in front of LHCf detector Energy flux for 7TeV 3 orders of magnitude reduction in dose from running to garage positions GeV/s/cm2 Oscar Adriani Perugia, 17/12/09

Improve the radiation resistance of LHCf Basic idea: Replace the plastic scintillator with more RadHard scintillators GSO Rearrange the order of silicon sensors to improve the silicon energy measurement Cross check for scintillator measurement Go back in the TAN for 5+5 TeV run at the end of 2010, after a beam test of the reassembled detector to precisely calibrate it Removal when Luminosity will be too high Go back in the 20xx for 7+7 TeV run Oscar Adriani Perugia, 17/12/09

Energy Resolutions for g Hit Position Selection 4<x<20, 4<y<20 Good energy resolution of the silicon layers !! Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 Conclusions LHCf is an interesting link between CR and accelerators LHCf is ready for operation since 2007 We got the first data just in these few weeks Detectors (and machine) are working very fine Preliminary physics plots Increase statistics and c.m. energy in 2010 First spectra will be published soon! Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 Survival efficiency p0 energy resolution Emin ~ 700GeV Geometrical Acceptance 3% @ 1TeV 10mm Lower Oscar Adriani Perugia, 17/12/09

Property of 2 candidates GSO Emission; 440nm (peak) Decay constant; 30-60ns Rad hardness (definition to be checked); 106-7Gy Laser; OK Yield; 10,000 photons/MeV Price; expensive! 700-800 CHF/piece PWO Emission; 430nm (peak) Decay constant; 2.1, 7.5, 26ns (3 components) Rad hardness; 104-5Gy Laser; to be tested Yield; generally very small (to be tested) Price; very cheap! 90CHF/piece Limited <30mm (surveying other factory) Temperature dependence? Some samples are already available in Nagoya and being tested Advantage Disadvantage Oscar Adriani Perugia, 17/12/09

Oscar Adriani Perugia, 17/12/09 Uniformity of Sum(dE) Map of sum(dE) of Scin. Map of sum(dE) of Si X Y Map(Si) / Map(Scin.) The silicon layers have more dE than scintillator layers due to additional dE by particles leaking out from the calorimeters. The difference increases near the top and left edges. Oscar Adriani Perugia, 17/12/09