LHCf Report Takashi SAKO

for the LHCf Collaboration

18-Dec-2009 CERN Main Auditorium

What is LHCf?

LHCf determines the energy spectra at zero degree for the calibration of hadron interaction models used in the Cosmic-Ray physics

Small calorimeters are installed either side of IP1 covering η>8.7 (8.4 with crossing angle)

ATLAS

LHCf Detector140m away from the interaction point

LHCf Detectors

Arm#1 Detector20mmx20mm+40mmx40mm4 XY SciFi+MAPMT

Arm#2 Detector25mmx25mm+32mmx32mm4 XY Silicon strip detectors

Sampling & imaging calorimeters either side of IP1 Two small tower calorimeters in both detectors (Tungsten 44r.l., 1.7λ, 16 plastic scintillator sampling layers, 4 position sensitive layers)

First Events with 900GeV collisions

Arm1(SciFi)

Longitudinal development

Lateral (X)Distribution

Lateral (Y)Distribution

First Events with 900GeV collisions

Arm2(Silicon)

Longitudinal development

Lateral (X)Distribution

Lateral (Y)Distribution

For Physics…

Shower Incident position

Red: collision + BGBlue: BG onlyEnergy spectrum

(to be calibrated to incident energy)

Particle ID

η=8.7

η=∞

O : collision + BG• : BG only

Sharp edge at η=8.7 is due to the elliptical beam pipe at D1 magnet between IP and the detector. Good evidence of collision particles!!

Compact EM showers

Results with Arm2

Shower Incident position Energy spectrum (to be calibrated to incident energy)

Particle ID

Summary and Thanks

Successful (almost perfect) commissioning with collision events

Possible to start physics with 6k shower events at 900 GeV collisions

Hope STABLE BEAMS at 2.4TeV collisions in 2010!Great thanks to CERN, LHC and ATLAS

Backup

LHCf Manipulator

Detectors are 10cm above beam plane during non-STABLE BEAMS Detectors move down to the beam plane only when STABLE BEAMS are declared

LHCf Aperture