LHCf Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment1 LHCf - an experiment for measuring the very forward production of neutral

Aspen Workshop on CRP, 15-19 Apr 2007

W.C. Turner – The LHCf Experiment 1

LHCf

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



LHCf

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



LHCf

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



LHCf

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



LHCf The LHCf detectors are located +/-140m from IP1 in LHC

IP1, ATLAS, LHCf

IP5, CMS

IP2, ALICE IP8, LHCb



LHCf

Interaction region

• 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

TAN neutral particle absorber



LHCf

Exploded view of the TAN and transition beam tube

IP, +140m

Instrumentation slot (96mm x 60.7mm x 1000mm)

~ 5m



LHCf

• 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 0 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(80m pitch)

The LHCf detectors are compact sampling and imaging calorimeters



LHCf

LHCf tower calorimeter illustrations

Arm#1 Arm#2

W plates

Scintillator

SciFi x-y layer Si microstrip x-y layer

25cm



LHCf

Arm#1 during assembly

Tower calorimeters

Light guides

32 PMTs + 8 MAPTs



LHCf Transverse projection of LHCfand beam pipe acceptance



LHCf

LHCf Arm#1 acceptance

“450 rad” <=> 140 rad xing angle“310 rad” <=> 0 rad xing angle



LHCf 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



LHCf

The LHCf team for 2006 SPS Beam Tests



LHCf

SPS H4 Setup



LHCf

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

SPS test beam 2004 results



LHCfLight efficiency correction measured

with a muon beam



LHCfShower leakage, energy

resolution, SPS data +MC

Fig. 7 MC simulation, include it?



LHCf MC simulation shows the shower leakage fraction is energy

independent



LHCf

Position resolution



LHCf

e-p/-n separation

LHCf = 44rad lengths, 2 hadron interaction lengths

L20-90 = discrimination parameter

= distance between 20% and 90% of longitudinal sum of shower particles



LHCf MC calculations of 0 mass and neutron energy resolutions

0 inv mass res ~ 5% Neutron energy res ~ 30%



LHCfArm#1 pre-installed Jan 07, Arm#1&2 final installation ~ Sep 07

IP1 140m away

TAN

LHCf Arm#1



LHCf

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 >10GeV ~20Hz 0 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 => 2sec bunch spacing matches max DAQ rate

–Single >100GeV rate ~ 800Hz

–Two 0 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

Documents

LHCf Aspen Workshop on CRP, 15-19 Apr 2007 W.C. Turner – The LHCf Experiment1 LHCf - an experiment for measuring the very forward production of neutral