Experimental Method: 2 independent detectors on both sides of IP The direct measurement of the p production cross section as function of pT is essential to correctly estimate the energy of the primary cosmic rays (LHC: 1017 eV) Simulation of an atmospheric shower due to a 1019 eV proton. Experimental Method: 2 independent detectors on both sides of IP Detector I Tungsten Scintillator Scintillating fibers Detector II Tungsten Scintillator Silicon mstrips INTERACTION POINT 140 m 140 m Beam line

ARM #1 detector scintillating fibers tungsten layers 2 towers (2.02.0cm2 and 4.04.0 cm2) ~47 r.l. (22  2.1 r.l. tungsten layers) 16 scintillator layers (3 mm thick) 4 pairs of scintillating fiber layers for tracking purpose (two orthogonal directions) scintillators Energy Impact point (h)

ARM #2 detector See TDR for details… We used LHC style electronics and readout 2 towers (2.52.5cm2 and 3.53.5 cm2) 44 r.l. (22  2 r.l. tungsten layers) 16 scintillator layers (3 mm thick) 4 pairs of silicon microstrip layers for tracking purpose (X and Y directions) Energy silicon layers Impact point (h) See TDR for details… scintillators tungsten layers

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)

Where we are with Arm1? Arm1 was fully assembled in Japan in July 2006 (scintillators + fibers + Tungsten) and brought to CERN for the Beam Test Arm1 was pre-installed in the real TAN last week!!!

Where we are with Arm2? Plastic scintillators + Light guides + Tungsten: Production in Japan finished in July 2006 They were brought in Florence end of July First Silicon module (Milestone INFN): Production in Florence finished in July 2006 Assembly of Arm2: It was done in Florence in August 1-15 Arm1 was brought at CERN for the beam test on August 16, 2006 To complete Arm2 3 more silicon moudules are needed They are now in production Arm2 will be pre-installed in the TAN end of April

Plastic scintillators + Light guides + Tungsten Florence clean room (thanks to CMS!!!!!)

The mechanics of the module 25 mm Light Guides + Scintillators Hybrid circuit Pace Chips Silicon sensor Kapton fanout Tungsten SiliconX SiliconY

The hybrid and the cables PACE3

The readout and ADC boards CCUM QPLL PLL

Beam test @ SPS Arm1 & Arm2 were delivered to Cern on August 16, 2006 They were set up for the beam test Beam period: August 28, September 4 H4 Test Area Electrons up to 200 GeV Protons up to 350 GeV Muons Goal of the test beam: Energy calibration of the calorimeter Measurement of the spatial resolution of silicon system Florence telescope (ADAMO) is used to precisely reconstruct tracks

Few plots of the beam test results… A high energy electron shower seen on x and y silicon X Y <Noise> ~ 5 ADC counts

Y Beam profile 200 GeV electrons X

Y Energy measured 200 GeV electrons Low Gain X

Y Energy measured 100 GeV electrons High Gain X

Y Energy measured 350 GeV protons High Gain X

SPARES

Transverse projection of detector #2 in the TAN slot Maximization of the acceptance in R (distance from beam center)

Position resolution of Arm #2 calorimeter 7 mm for 1.8 TeV photons

p0 geometrical acceptance Arm #2 Arm #1

p0 mass resolution Arm #1 DE/E=5% 200 mm spatial resolution Dm/m = 5%