LHCf - an experiment for measuring the very forward production of neutral particles at the LHC W.C. Turner LBNL for the LHCf Collaboration Presented at the Aspen Workshop on Cosmic Rays 15-19 Apr 2007 Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

W.C. Turner – The LHCf Experiment The LHCf Participants Nagoya University, Japan K. Fukui, Y. Itow, T. Mase, K. Masuda, Y. Matsubara, H. Matsumoto, H. Menjo, T. Sako, K. Taki, H. Watanabe Kanagawa University, Japan T. Tamura Konan University Y. Muraki (Spokesperson), Waseda University, Japan K. Kasahara, Y. Shimizu, S. Torii Shibaura Inst. of Tech., Japan K. Yoshida University of Florence, Italy O. Adriani, L. Bonechi, M. Bongi, G. Castellini, R. D’Alessandro, P. Papini University of Catina, Italy A. Tricomi Univerity of Valencia, Spain A, Faus-Golffe, J. Valesco CERN, Switzerland D. Macina, A.-L. Perrot Ecole-Polytechnique Palaiseau, France M. Hauguenauer Lawrence Berkeley Laboratory, USA W.C. Turner Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

W.C. Turner – The LHCf Experiment Outline Motivation and History of LHCf The LHC Environment The LHCf Detectors Anticipated LHCf Performance SPS Beam Test and Monte Carlo Results Installation and Schedule Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

Motivation and History Use 7+7 TeV pp collisions to benchmark neutral particle production cross sections at 1017eV laboratory equivalent energy Useful for cosmic ray simulations, contribute to resolution of super GZK and composition questions Previous experiment UA7 performed at SPPS 400 + 400 GeV, 1014 eV (E. Pare et al, Phys. Lett., B242 (1990)) Present Experiment LOI submitted to LHCC in May 2004 and TDR approved in 2006 Prototype detector tested at SPS H4 in 2004 and final detector in 2006 First detector installed at IP1 in Jan 2007 Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

The LHCf detectors are located +/-140m from IP1 in LHC IP1, ATLAS, LHCf IP5, CMS IP2, ALICE IP8, LHCb Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

W.C. Turner – The LHCf Experiment Interaction region TAN neutral particle absorber The TAN absorbs forward neutral collision products (mostly neutrons and photons) and is placed in front of the outer beam separation dipole D2 to protect superconducting magnets LHCf exploits the opportunity to install detectors inside the TAN for measurement of very forward neutral particle production cross sections Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

Exploded view of the TAN and transition beam tube IP, +140m Instrumentation slot (96mm x 60.7mm x 1000mm) ~ 5m Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

W.C. Turner – The LHCf Experiment The LHCf detectors are compact sampling and imaging calorimeters Measure 100 GeV - 7 TeV gammas and neutrons Detectors are located on both sides of IP1 (Arm#1 and Arm#2) for coincidence studies and redundancy Each Arm consists of two “tower” calorimeters for separately measuring the two gammas from p0 decay 44 radiation lengths of W plates interleaved with 16 scintillation panels (overall length 25cm) Transverse cross sections 20mm x 20mm + 40mm x 40mm Arm#1 and 25mm x 25mm + 32mm x 32mm Arm#2 Four position sensitive layers measure the transverse center of the showers Arm#1 SciFi (1mm x1 mm) Arm#2 Si microstrip detectors(80mm pitch) Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

W.C. Turner – The LHCf Experiment Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

W.C. Turner – The LHCf Experiment Arm#1 during assembly 32 PMTs + 8 MAPTs Light guides Tower calorimeters Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

Transverse projection of LHCf and beam pipe acceptance Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

W.C. Turner – The LHCf Experiment LHCf Arm#1 acceptance “450 mrad” <=> 140 mrad xing angle “310 mrad” <=> 0 mrad xing angle Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

PMT + scintillator linearity ~+/- 2% over anticipated dynamic range Dynamic range req’d: 1 mip (muon calibration of light collection efficiency) to 7x104 mips (7 TeV gamma shower max) “mips” simulated with Nitrogen Laser excitation of scintillator Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

W.C. Turner – The LHCf Experiment The LHCf team for 2006 SPS Beam Tests Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

W.C. Turner – The LHCf Experiment SPS H4 Setup Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

W.C. Turner – The LHCf Experiment SPS test beam 2004 results Beam Energy(GeV) Measurements Electron beam 50, 100, 150, Simulate photon showers, 200 measure energy resolution, spatial resolution and shower leakage Proton beam 150, 350 Simulate neutron showers Muon beam 150 Obtain calibration for single mip, measure non-uniformity of light collection efficiency Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

Light efficiency correction measured with a muon beam Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

Shower leakage, energy resolution, SPS data +MC Fig. 7 MC simulation, include it? Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

MC simulation shows the shower leakage fraction is energy independent Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

W.C. Turner – The LHCf Experiment Position resolution Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

W.C. Turner – The LHCf Experiment e-p/g-n separation LHCf = 44rad lengths, 2 hadron interaction lengths L20-90 = discrimination parameter = distance between 20% and 90% of longitudinal sum of shower particles Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

MC calculations of p0 mass and neutron energy resolutions p0 inv mass res ~ 5% Neutron energy res ~ 30% Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

Arm#1 pre-installed Jan 07, Arm#1&2 final installation ~ Sep 07 IP1 140m away LHCf Arm#1 TAN Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment

Plans for future operation with LHC “450 x 450 GeV Engineering Run” ~Oct - Dec 2007 (Could get delayed to 2008 owing to inner triplet problems! Will know in mid-May.) Observe first pp collisions and background rates due to beam-gas, beam halo collisions etc Low event rates owing to reduced acceptance, single g >10GeV ~20Hz p0 reconstruction below background “Stage 1” 7 TeV x 7 TeV beam commissioning ~Jun - Sep 2008 Luminosity ~1029cm-2 s-1, inelastic collision rate ~ 8kHz 43 x 43 bunches => 2msec bunch spacing matches max DAQ rate Single g>100GeV rate ~ 800Hz Two g p0 rate ~ 80Hz (106 events in 3.5 hrs) Two arm coincidence ~ 80Hz Neutrons >100GeV ~ 4kHz Remove LHCf when Luminosity > 1030cm-2 s-1 to avoid rad. damage Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment