Massimo Bongi - INFN Florence LHCf Collaboration 7th International Conference on Radiation Effects on Semiconductor Materials, Detectors and Devices (RESMDD) 15-17 October 2008 Florence Astroparticle Physics at LHC: the LHCf experiment ready for data taking Massimo Bongi - INFN Florence LHCf Collaboration Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Massimo Bongi - RESMDD08 - 15 October 2008 - Florence Overview Cosmic-Ray Physics goals Ultra-High-Energy CR spectrum composition of High-Energy CR (Monte Carlo codes calibration) LHCf detectors and experimental set-up Physics performance Current status Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Ultra-High-Energy Cosmic Rays Experimental observations: (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 Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

UHECR spectra and the GZK cutoff AGASA x 0.9 HiRes x 1.2 Yakutsk x 0.75 Auger x 1.2 Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Calibration of models with experimental data UHECR spectra and the GZK cutoff GZK cutoff would limit energy to 1020eV (for protons, due to Cosmic Microwave Background): p + γ(2.7K)  Δ  N + π Different hadronic interaction models give different answers for the primary CR energy estimate. (for instance, AGASA reports 18% as systematic uncertainty in energy determination, 10% being due to the interaction model) Calibration of models with experimental data Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Massimo Bongi - RESMDD08 - 15 October 2008 - Florence HECR composition Xmax(g/cm2) 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. PROTON IRON UA7 LHCf Energy(eV) Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

HECR composition Auger Xmax measurements favors heavier composition as the energy increases Anisotropy would favor proton primaries (AGN correlation) Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Development of atmospheric showers 1019 eV proton The dominant contribution to the shower development comes from particles emitted at low angles in the interaction of the primary CR (forward region). The knowledge of the π-production cross-section in the forward region is needed in order to correctly estimate the energy of the primary CR. The highest-energy data currently available are at 1014 eV (UA7@SppS, 1990) Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Astroparticle Physics at LHC 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. 7 TeV + 7 TeV proton collisions at LHC (ECM = 14 TeV) correspond to ELAB = 1017 eV (ELAB ≈ ECM2/(2mp)) Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

The LHCf Collaboration CERN D.Macina, A.L. Perrot USA LBNL Berkeley: W. Turner FRANCE Ecole Politechnique Paris: M. Haguenauer JAPAN: STE Laboratory Nagoya University: K.Fukui,Y.Itow, T.Mase, K.Masuda,Y.Matsubara, H.Menjo,T.Sako, K.Taki, H. Watanabe Waseda University: K. Kasahara, M. Mizuishi, Y.Shimizu, S.Torii Konan University: Y.Muraki Kanagawa University Yokohama: T.Tamura Shibaura Institute of Technology: K. Yoshida SPAIN IFIC Valencia: A.Fauss, J.Velasco ITALY Firenze University and INFN: O.Adriani, L.Bonechi, M.Bongi, G.Castellini, R.D’Alessandro, P.Papini, S. Ricciarini, A. Viciani Catania University and INFN: A.Tricomi Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Massimo Bongi - RESMDD08 - 15 October 2008 - Florence The LHC ring ATLAS (IP1) Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Massimo Bongi - RESMDD08 - 15 October 2008 - Florence Experimental set-up INTERACTION POINT IP1 (ATLAS) Beam line Arm#2 Tungsten Scintillator Silicon microstrips Arm#1 Scintillating fibers 140 m Two independent electromagnetic calorimeters equipped with position sensitive layers, on both sides of IP1 will measure energy and position of γ from π0 decays. Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Massimo Bongi - RESMDD08 - 15 October 2008 - Florence Experimental set-up Charged particles Neutral particles Beam pipe Protons The detectors are installed in the TAN region, where the beam pipe splits into 2 separate tubes. Charged particles are deflected away, only neutral particles hit the detectors. LHCf 96 mm Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Arm#1 detector Scintillating Fibers 4 pairs of layers (6, 10, 32, 38 r.l.) tracking measurements 2 towers stacked vertically with 5 mm gap 24 cm long upper: 4.0 cm x 4.0 cm area lower: 2.0 cm x 2.0 cm area Absorber 22 tungsten layers 7mm – 14 mm thick (W: X0 = 3.5mm, RM = 9mm) Plastic Scintillator 16 layers 3 mm thick trigger and energy profile measurements Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Arm#2 detector Silicon Microstrip (from ATLAS SCT) 4 pairs of layers (6, 12, 30, 42 r.l.) tracking measurements 2 towers stacked on their edges and offset from one another 24 cm long upper: 3.2 cm x 3.2 cm area lower: 2.5 cm x 2.5 cm area Absorber 22 tungsten layers 7mm – 14 mm thick (W: X0 = 3.5mm, RM = 9mm) Plastic Scintillator 16 layers 3 mm thick trigger and energy profile measurements Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

The detectors are ready since 2007 Arm#1 detector Arm#2 detector Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Massimo Bongi - RESMDD08 - 15 October 2008 - Florence Front Counter 2 Scintillator Counters installed in front of Arm#1 and Arm#2 segmented in 2 X and 2 Y slices check the beam quality, reduce background events and decide whether to move Arm#1 and Arm#2 in the operating position from the “garage” position Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Massimo Bongi - RESMDD08 - 15 October 2008 - Florence LHCf Physics Single photon spectrum p0 mass reconstrucion (1 photon in each tower) p0 reconstruction is an important tool for energy calibration (p0 invariant mass constraint) Basic concept: 2 towers for p0 reconstruction Smallest tower on the beam (to reduce multiple hits) Dimension of the tower  Moliere radius Maximum acceptance (given the LHC and TAN constraints) Simulation has been used to understand the physics performances Beam tests in 2004, 2006 and 2007, to evaluate: energy resolution spatial resolution of the tracking part Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

LHCf acceptance on PT-E  plane 140 Beam crossing angle Detectable events A vertical beam crossing angle > 0 will increase the acceptance of LHCf Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

LHCf single g geometrical acceptance Mechanical manipulators allows to remotely move LHCf: some runs with the detectors vertically shifted few cm will allow to cover the whole kinematical range Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

LHCf : Monte Carlo discrimination 106 generated LHC interactions ~ min exposure @1029 cm-2s-1 luminosity already allows discrimination between various models (5% energy resolution included) Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

LHCf: model dependence of neutron energy distribution Neutron spectra at detector front 30% energy resolution included Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

LHCf energy resolution 2.5 x 2.5 cm2 tower 2.0 x 2.0 cm2 tower Energy resolution ~ 3% at high energy, even for the smallest tower Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Pion reconstruction   Calorimeters 350 GeV Proton beam (not in scale)  Carbon target (3 cm) in the slot used for beam monitor 9.15 m Arm#1 >107 proton on target (special setting from the SPS people) Egamma=18GeV Shower Profile @ First SciFi Layer Calorimeters 20mm X 40mm Y Egamma=46GeV Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Pion mass reconstruction  250 pion events triggered (in a quite big background) Δm ~ 8 MeV Δm/m ~ 6% Preliminary (MeV) Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Arm#1 position resolution 200 GeV electrons σX=172µm Number of event σX[mm] x-pos[mm] E[GeV] σY=159µm σY[mm] Number of event y-pos[mm] E[GeV] Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Arm#2 position resolution 200 GeV electrons σX=40µm σX[µm] x-pos[mm] E[GeV] σY=64µm σY[µm] y-pos[mm] Alignment has been taken into account Massimo Bongi - RESMDD08 - 15 October 2008 - Florence E[GeV]

Radiation damage studies Dose evaluation on the basis of LHC reports on radiation environment at IP1 <10 Gy/day @ 1029 cm-2s-1 luminosity are expected some tens Gy during 1 week operation lead to ~10% light output decrease scintillators will be monitored and decrease of light output will be corrected by laser calibration Silicon detectors from ATLAS SCT (see next talk!) test of Scintillating fibers and scintillators 30 kGy Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

LHCf Arm#1 – Installation completed Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

LHCf Arm#2 – Installation completed Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

LHCf ready for data taking The LHCf control room in the ATLAS area Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Massimo Bongi - RESMDD08 - 15 October 2008 - Florence Dummy event Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

LHCf ready for data taking On September 10 we observed some signals on Front Counters, with Arm#1 and Arm#2 in garage position for safety reasons That day the Atlas BPTX signal was still not available (no info on the real bunches in the Atlas zone) On September 11 Atlas gave us the synchronized BPTX signals, and we could take Front Counter data by using this signal (still in garage position) We are measuring beam-gas interactions from beam2 on Arm#1 side Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

LHCf ready for data taking Massimo Bongi - RESMDD08 - 15 October 2008 - Florence

Massimo Bongi - RESMDD08 - 15 October 2008 - Florence Conclusions Detectors construction and installation completed in 2008 Preparation for running completed First beam gas events acquired We are ready for LHC data Massimo Bongi - RESMDD08 - 15 October 2008 - Florence