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

Massimo Bongi - RESMDD October 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 - RESMDD October Florence Ultra-High-Energy Cosmic Rays Experimental observations: (shower of secondary particles) lateral distribution longitudinal distribution particle type arrival direction Extensive Air Showers Astrophysical parameters: (primary particles) spectrum composition source distribution origin and propagation Air shower development (particle interaction in the atmosphere)

Massimo Bongi - RESMDD October Florence UHECR spectra and the GZK cutoff AGASAx 0.9 HiResx 1.2 Yakutskx 0.75 Augerx 1.2

Massimo Bongi - RESMDD October Florence UHECR spectra and the GZK cutoff GZK cutoff would limit energy to eV (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 - RESMDD October Florence HECR composition Energy(eV) X max (g/cm 2 ) PROTON IRON UA7 The depth of the maximum of the shower X max in the atmosphere depends on energy and type of the primary particle. Different hadronic interaction models give different answers about the composition of HECR. LHCf

Massimo Bongi - RESMDD October Florence HECR composition Auger X max measurements favors heavier composition as the energy increases Anisotropy would favor proton primaries (AGN correlation)

Massimo Bongi - RESMDD October Florence Development of atmospheric showers 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 eV 1990)

Massimo Bongi - RESMDD October 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 (E CM = 14 TeV) correspond to E LAB = eV (E LAB ≈ E CM 2 /(2m p ))

Massimo Bongi - RESMDD October Florence The LHCf CollaborationITALY 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 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 FRANCE Ecole Politechnique Paris: M. Haguenauer USA LBNL Berkeley: W. Turner CERN D.Macina, A.L. Perrot

Massimo Bongi - RESMDD October Florence The LHC ring ATLAS (IP1)

Massimo Bongi - RESMDD October Florence Experimental set-up INTERACTION POINT IP1 (ATLAS) Beam line Arm#2TungstenScintillator Silicon microstrips Arm#1TungstenScintillator 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 π 0 decays.

Massimo Bongi - RESMDD October Florence Experimental set-up 96 mm Charged particles Neutral particles Beam pipe Protons LHCf 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.

Massimo Bongi - RESMDD October Florence Arm#1 detector Plastic Scintillator 16 layers 3 mm thick trigger and energy profile measurements Absorber 22 tungsten layers 7mm – 14 mm thick (W: X 0 = 3.5mm, R M = 9mm) 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

Massimo Bongi - RESMDD October Florence Arm#2 detector Plastic Scintillator 16 layers 3 mm thick trigger and energy profile measurements 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: X 0 = 3.5mm, R M = 9mm)

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

Massimo Bongi - RESMDD October 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 - RESMDD October Florence LHCf Physics  Single photon spectrum   0 mass reconstrucion (1 photon in each tower)  0 reconstruction is an important tool for energy calibration (  0 invariant mass constraint) Basic concept: 2 towers for  0 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 - RESMDD October Florence Detectable events 140 Beam crossing angle LHCf acceptance on P T  -E  plane A vertical beam crossing angle > 0 will increase the acceptance of LHCf

Massimo Bongi - RESMDD October Florence LHCf single  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 - RESMDD October Florence LHCf : Monte Carlo discrimination 10 6 generated LHC interactions ~ min 29 cm -2 s -1 luminosity already allows discrimination between various models (5% energy resolution included)

Massimo Bongi - RESMDD October Florence Neutron spectra at detector front30% energy resolution included LHCf: model dependence of neutron energy distribution

Massimo Bongi - RESMDD October Florence LHCf energy resolution 2.5 x 2.5 cm 2 tower2.0 x 2.0 cm 2 tower Energy resolution ~ 3% at high energy, even for the smallest tower

Massimo Bongi - RESMDD October Florence Leakage Correction (Arm#1 prototype) correction 2 mm

Massimo Bongi - RESMDD October Florence Pion reconstruction 9.15 m  350 GeV Proton beam Carbon target (3 cm) in the slot used for beam monitor Arm#1 (not in scale) E gamma =18GeV Shower First SciFi Layer Calorimeters 20mm X 40mm X Y Y E gamma =46GeV >10 7 proton on target (special setting from the SPS people) 

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

Massimo Bongi - RESMDD October Florence Arm#1 position resolution Number of event x-pos[mm] y-pos[mm] 200 GeV electrons E[GeV] σ X =172µm σ Y =159µm σ X [mm] σ Y [mm]

Massimo Bongi - RESMDD October Florence Arm#2 position resolution x-pos[mm] y-pos[mm] Alignment has been taken into account 200 GeV electrons E[GeV] σ X =40µm σ Y =64µm σ X [µm] σ Y [µm]

Massimo Bongi - RESMDD October Florence Radiation damage studies 30 kGy   Dose evaluation on the basis of LHC reports on radiation environment at IP1   < cm -2 s -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

Massimo Bongi - RESMDD October Florence LHCf Arm#1 – Installation completed

Massimo Bongi - RESMDD October Florence LHCf Arm#2 – Installation completed

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

Massimo Bongi - RESMDD October Florence Dummy event

Massimo Bongi - RESMDD October 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 - RESMDD October Florence LHCf ready for data taking

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