Current status of the LHCf experiment Yasushi Muraki (Konan University)

1. A history on hadron physics

2. Previous experiment CERN UA7

3. Current experiment a ｔ LHC: LHCf

Measurement of π0 cross-section emitted in a very forward region by

the pp collisions at E0=10 17eV

Historical debate in the field of cosmic ray physics

Around 1980, there was a big debate in the field of cosmic ray physicsWhether or not the nuclear interaction process is changing at 100 TeV?Or it just reflects an increase of heavy primary component like Fe in the primary component of cosmic rays.The data showed only rapid development of the cascade showers in the atmosphere.

A typical example of such a debate:

Chacaltaya emulsion group → new interaction process like Centauro

Fuji-Tibet group: increase of iron component

If we can launch again a new heavy calorimeter in the space, we can resolve this problem immediately, but the experiment is very expensive. 1987 in Moscow conference..

1981

The CERN UA7 experiment 1985-86, Muraki, M. Haguenauer(UA4) et al.

Roman pot and Silicon calorimeters are used

The energy is calibrated by π0 peak Eric Paré et al, Phys. Lett. B242 (1990) 531.

Result : Feynman scaling does hold at very forward region at 150TeV

New debate in the very high energy region

We must need again by an accelerator experiment.

To establish the GZK cut-off problem, we need a calibration experiment.

To calibrate the Monte Carlo Codes

that are often used for the reduction of the

incident energy of air showers at LHC.

The position of shower maximumKnapp et al, Astroparticle Physics, 19(2003) 77

UA7

LHCf

Fe incidence

How to do it?

Detector location

Y Chamber

LHCf two kinds of tower calorimeter

Arm#1 Arm#2

W plates

Scintillator

SciFi x-y layer Si microstrip x-y layer

25cm

Arm#1 during assembly

Tower calorimeters

Light guides

32 PMTs + 8 MAPTs

independent detectors on both sides of IPXindependent detectors on both sides of IPX

INTERACTION POINT

Beam line

Detector II

Tungsten

Scintillator

Silicon strips

Detector I

Tungsten

Scintillator

Scintillating fibers

140 m 140 m

1. Redundancy2. Background rejection (especially beam-gas)3. Physics single diffractive/double diffractive

Transverse projection of LHCfand beam pipe acceptance (coverage)

Two calorimeters are lifted up and down by the manipulators

IP1 140m away

TAN

LHCf Arm#1

Monte Carlo ray energy spectrum106 generated LHC interactions 1 minute exposure

K.Fukui, Y.Itow, T.Mase, K.Masuda, Y.Matsubara, H.Menjo, T.Sako, K.Taki Solar-Terrestrial Environment Laboratory, Nagoya University, Japan

K.Yoshida Shibaura Institute of Technology, Japan

K.Kasahara, M.Mizuishi, S.Torii Waseda University, Japan

T.Tamura Kanagawa University, Japan

Y.Muraki Konan University

Y.Shimizu ICRC, University of Tokyo, Japan

M.Haguenauer Ecole Polytechnique, France

W.C.Turner LBNL, Berkeley, USA

O.Adriani, L.Bonechi, M.Bongi, R.D’Alessandro, M.Grandi, P.Papini, S.Ricciarini, G.Castellini, A. Viciani INFN, Univ. di Firenze, Italy

A.Tricomi INFN, Univ. di Catania, Italy

J.Velasco, A.Faus IFIC, Centro Mixto CSIC-UVEG, Spain

D.Macina, A-L.Perrot CERN, Switzerland

The LHCf experiment (Apr. 2008-)

IP1, ATLAS, LHCf

IP5, CMS

IP2, ALICE IP8, LHCb

Current status of the LHCf experiment

The two detectors have been installed now at the collision point IP1.The beam will circulate in the 28km tunnel on September 10th (Today! ).The beams will make collisions within one month.The beams will be accelerated to 5TeV

until the end of this year. √ s=10 TeV

September 10• Before we startBeam down the lines to the TEDs OK (check to TDIs)• All screens in and visible (or easily made so)• Synoptic display and trajectory display

• Primary aim: Get 2 109 protons round ring 1• Get 2 109 protons round ring 2• Aperture ~clear in both rings

• Icing: Inject and dump after > 1 turn• Interleaved injection into both rings (as we did Sunday 24th)

• Dreaming: Get 5 109protons to circulate in ring 1• Get 5 109protons to circulate in ring

R.Bailey, September 2008

By R.Bailey, September 2008

Concluding remarks

Concluding Remarks

★A very important data will be obtained without change of present LHC projects.

★The data will become extremely useful not only for cosmic ray physics, but also for high energy physics.

★ The data will be used for a long time.

Other remarks＊ We also want to measure N-N or p-N or

　　 or N-Fe collisions. ( N= N2 and O2)＊ We also get another important data on neutro

ns and K0s and the inelesticity.

We can measure the region ofphotons with XF>0.05 by this experiment.

The position of shower maximumKnapp et al, Astroparticle Physics, 19(2003) 77

UA7

LHCf

Fe incidence

The background

The beam gas contamination We estimate beam-beam: beam-gas = 2 : 1 @ L= 1029 and early stagebut at the later stage = 1: 0.01 @ L= 1029 and later stage At the beginning, taking account of the acceptance for the beam-gas event by the M.C.

calculation, we found that the ratio betweenbeam-beam : beam-gas = 10 : 1 (contamination is ~10%) However if we will take arm#1*arm#2 trigger, it will be reduced to 1000:1. Unfortunately a that time we may loose pure single diffractive event. Therefore we must repeat the data-taking after machine conditioning. However the above value is estimated for the high luminosity case and in factin the early low luminosity case, the gas in the beam pipe would be not somuch. We must ask a calculation to the CERN vacuum group.

Two production cross-sections were assumed for Monte Carlo :A and B.

We have made a similar detector what we had proposed and made a test experiment using NA beam line of CERN.The detector was bombarded to the electron, muon and proton beams with energies 50-250 GeV.The position of the beam incidence was measured by the silicon detector.

At 140m away from the interaction regionthere is a gap of 9cm that can put a small calorimeter

IP, +140m

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

~ 5m

We could install an electromagnetic calorimeter there