lorenzo bonechi ( infn – firenze) on behalf of the lhcf collaboration

Lorenzo Bonechi (INFN – Firenze)on behalf of the LHCf Collaboration

CSN122 September 2011, Bari

LHCf: status and perspectives

22 September 2011 2L.Bonechi, CSN1, Bari

Outline

• Overview of LHCf– Cosmic rays in the atmosphere and hadronic interaction models– Detection of neutral particles at low angle at LHC– Description of detectors

• Data analysis– Published results for single in 7 TeV pp interactions– On-going analysis for at 7 TeV and single at 900 GeV

• Simulation of p-Pb interactions• Upgrade of detectors for new measurements• Summary


Purpose of the experiment• Experimental measurement:

– Precise measurement of neutral particle (, 0 and n) spectra in the very forward region at LHC

• 7 TeV + 7 TeV in the c.m. frame 1017 eV in the laboratory frame:– We are simulating in the biggest’s world laboratory what happens in nature

when a Very High Energy Cosmic Ray interacts in the atmosphere• Why in the very forward region?

– Because the dominant contribution to the energy flux in the atmospheric shower development is carried on by the very forward produced particles

LHC


Detectors measure energy andimpact point of from 0 decays

e.m. calo tracking layers

Two independent detectors on bothsides of IP1 Redundancy Background rejection (esp. beam-gas)

Charged particles

Neutralparticles

Beam pipe

Protons

Detectors are located Inside the

TANs (absorbers forneutral particles)

96mm

Recombination Chamber

The LHCf location


Details of the detectors

40mm

20mmPerformances Energy resolution (> 100GeV): < 5% for photons and 30% for neutrons Position resolution for photons: < 200μm (Arm#1) and 40μm (Arm#2)

Sampling and imaging E.M. calorimeters Absorber: W (44 r.l , 1.55λI ) Energy measurement: plastic scintillator tiles 4 tracking layers for imaging: XY-SciFi(Arm#1) and XY-Silicon strip(Arm#2) Each detector has two calorimeter towers, which allow to reconstruct 0

Front Counters• thin scintillators 80x80 mm • monitoring of beam condition •Van der Meer scan

Arm1

25mm

32mm

Arm2


Arm#1 Detector Arm#2 Detector90mm290mm


Summary of data taking 2009-2010

Data taking with Stable Beams at (450 + 450) GeV • Dec 6th – Dec 15th 2009 and May 2nd – May 27th 2010• 42 hours for physics

Data taking with Stable Beams at (3.5 + 3.5) TeV• Mar 30th – Jul 19th 2010• 150 hours for physics with different setups

• Different vertical positions to increase the accessible kinematical range• Runs with or without 100 rad beam crossing angle

Shower Gamma Hadron

Arm1 46,800 4,100 11,527Arm2 66,700 6,158 26,094

Shower Gamma Hadron π0

Arm1 172,263,255 56,846,874 111,971,115 344,526

Arm2 160,587,306 52,993,810 104,381,748 676,157


Analysis of (3.5+3.5) TeV data• Clean sub-set of data (nominal config., no

beam crossing angle, low luminosity) Nominal config., no beam crossing angle Low luminosity (measured by front counters)

• Particle IDentification Study of longitudinal energy deposit (L90% is the

depth in calorimeter for containment of 90% of the total released energy)

• Selection of single gamma events Study of transverse energy deposit

• Energy reconstruction Based on total energy deposit in scintillator tiles

• Common pseudo-rapidity region for Arm1/2 η>10.94 and 8.81<η<8.9

Distribution of L90%

Multiple hit event (seen on one silicon layer)

Arm1 Arm2


Published results for single at 7 TeVAdriani et al., Physics Letters B 703 (2011) 128–134

Gray hatch : Systematic Errors

Magenta hatch: MC Statistical errors

DPMJET 3.04 SIBYLL 2.1EPOS 1.99PYTHIA 8.145QGSJET II-03

(small tower) (large tower)


Further analysis

s 7 TeV - : energy and pt (or ) distribution (in progress)- Single : pt (or ) distribution

s 900 GeV - : no- Single : energy and pt (or ) distribution (in progress)

Lower priority: hadrons (n)


m 140= R

I.P.1

1(E1)

2(E2)

140mR21EEM

• 0’s are the main source of electromagnetic secondaries in high energy collisions

• The mass peak is very useful to check the detector performances and to estimate the systematic error on the energy scale

25 mm tower 32 mm tower

Silicon -stripX-view

Silicon -stripY-view

Selected data (2010 May 15, 17:45-21:23, Fill# 1104)No crossing angle, pile up is negligible (~0.2%)Low luminosity : (6.3-6.5)x1028cm-2s-1

DAQ Live Time : 85.7% (Arm1), 67.0% (Arm2)Integrated lumi : 0.68 nb-1 / 0.53nb-1 (Arm1/2)MC simulationsDPMJET 3.04, QGSJET II-03, SYBILL 2.1, EPOS 1.99 and PYTHIA8.145Propagation in beam pipe and detector response are considered.In each model 107 collisions are generated.

Neutral pions at 7 TeV

L.Bonechi, CSN1, Bari

Large tower

Small tower

Type-I event

This has been dealt with so far.It can cover wide opening angle.Thus this type dominates in low energy region.While due to unavoidable gap between each tower, sensitivity in high energy is rather worse.

1

2

22 September 2011

Large tower

Small tower

Type-II event

1

2

Now it is possible to analyze this type of events thanks to the improvement of multi-hit reconstruction.Tight opening angle(~high E) can be detected by this type of π0.Mass peak is still wide.

Neutral pions at 7 TeV (Arm1) (2)

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L.Bonechi, CSN1, Bari22 September 2011

Neutral pions at 7 TeV (Arm1) (3)

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LHCf-Arm1Data 2010(Large tower)

Blue solid : TotalBlue dashed : SignalCyan : BackGroundYellow : Fitting error

LHCf-Arm1Data 2010

PRELIMINARY

PRELIMINARY

(Data-MC)/MC~7.8% (due mainly to energy scale)Type-II has a peak around 135MeV, but BG reduction is biggest homework

For ref, values in DPMJET3<Mγγ> = 135.2MeV σ = 4.9MeV

No acceptance correction No acceptance correction

Single photons at 900 GeV


This analysis is in a raw preliminary status for Arm1:– Under development

– Energy reconstruction function is new• special one for low energy region:

– PID threshold• PID criteria is same as 7TeV• Threshold is updated

– Multi-hit cut– Not yet included (future plan)

– Systematic error– Luminosity normalization– All other corrections

For Arm2 we are generating Monte Carlo events (one month needed to complete the generation for all models)


Future measurements: proton – lead ionThe study of proton interactions with nuclei in the forward region is important for cosmic ray physics, because strictlyrelated to the interactions of primary cosmic rays with the atmosphere.Ideally we would like to measure the interaction of protonswith Nitrogen ions (to reproduce real atmospheric showers)or at least with light ions.

Anyway the study of proton – heavy ion interaction in theforward region can be important to study the scalingproperties of cross sections with respect to the pp case ( nuclear modification factors and parton density saturation)Interaction p-Pb @ LHC in 2012 (3.5 TeV protons).We are studying the impact of our measurement.

LPCC @ CERN on 17 October 2011(Hopefully in the near future also proton-light ion run will befeasible, for example at RHIC!!!)


proton – lead ion simulation

• Simulating protons with energy Ep = 3.5 TeV

– Energy per nucleon for ion is given by and results 1.38 TeV/nucl (at

LHC the momentum must be the same for both beams)• Arm2 geometry considered on both sides in this simulation• Detector response not included yet

Beam line

140 m 140 m

p-beam Pb-beam

Left-side or “Pb-remnant side”

Right-side or “p-remnant side”

pN EAZ

E

This simulation is based on the EPOS (version 1.99) interaction modelDPMJET III simulation is also under development


proton – lead ion: -ray hit map Pb-remnant side p-remnant side


proton – lead ion: neutron hit map p-remnant side, E > 500 GeVp-remnant side, E > 100 GeV

Only the proton remnant side is considered in these plots, because on the ion-remnant side a huge peak due to the neutron fragment is found just coming along the beam line.

E>100GeV

E>500GeV


p – Pb: multiplicities on small tower

n

Pb –remnant side

p –remnant side

Too many neutronfragments!!!


p – Pb: multiplicities on big tower

n

Pb –remnant side

p –remnant side


All energies

E>10GeV

Pseudo rapidity distribution

p – Pb: -ray pseudo rapidity distribution


p – Pb: neutron pseudo rapidity distribution

All energies

E>10GeV


p – Pb: energy vs pseudo-rapidity

PHOTONSNEUTRONS


PHOTONSSMALL TOWER

PHOTONSBIG TOWER

NEUTRONSSMALL TOWER

NEUTRONSBIG TOWER

p – Pb: energy spectra in p-remnant side


Upgrade of detectors Rad-hard detectors are needed for operations at √s=14TeV √s=7TeV operation in 2010 　　　　　　　√ s=14TeV operations

Dose ~ 200Gy 　　　　　　　　 Exp. Dose 　 ~2000Gy 10

We replaces some parts to radiation harder hard ones(no change to detector design)

Plastic Scintillators （ Eljen Technology 　EJ260 ）

Scintillating Fibers （ KURARAY SCSF- 38 ）

Silicon Strip Detectors

GSO scintillatorsGSO scintillator bars(use current ones)

Upgraded DetectorCurrent Detector


Radiation hardness: scintillators

GSO Scintillators Test of GSO bar belts 1mmx1mm×20mmx5

EJ-260 GSO

Radiation hardness (Gy) 100 106

Density (g/cm3) 1.02 6.71X0 (cm) 14.2 1.38Decay time (ns) 9.6 30-60

Light yield （ NaI=100） 19.6 20

Specification of both EJ-260(current detector)and GSO(upgraded detector)

Relative Light Yield as a function of dose. The results have been taken by irradiation of carbon beam at HIMAC* (290MeV/n)*HIMAC : Heavy Ion Medical Accelerator in Chiba


Upgrade of silicon detectors

1. Remove pedestal fluctuation (1nd level upgrade)2. Reduce the saturation effect at E > 1 TeV (2nd level upgrade)

– Very important improvement for higher energy LHC runs– It requires production of completely new silicon modules

3. Improve the energy resolution for the silicon system (2nd level upgrade)– Useful cross check for scintillators

1st level upgrade before proton-lead run2nd level upgrade before pp at 14 TeV run

SOME IMPORTANT POINTS UNDER INVESTIGATION :


Upgrade: pedestal fluctuation

Silicon modules are the black ones in the picture.

This modification requiresopening the detector ,cutting the power lines and fixing some new simple electric circuit.

1st level upgrade (minor intervention!)To avoid pedestal fluctuation (observed also for low energy photons) we will test soon some simple circuits to be installed on the LV power lines to the front-end. Then we want to decouple the powering of the two half-boards of each front-end.


Upgrade: saturation effect2nd level upgradeTo reduce the saturation effect for high energy releases in silicon layers there are several possibilities that are under discussion and investigation. Decision are not yet fixed. Main points are:

• No possibility to change the Pace3 chips with higher dynamic range preamplifiers

• We should operate directly on the silicon side1. Reducing the silicon depleted thickness to produce less charge

a. Decreasing the bias voltage (not safe)b. Producing new thin silicon detectors (safer, but we loose the

possobility to detect MIPs)2. Reducing the charge collected by the readout strips

a. Connecting the floating strips to ground (we save the sensitivity to MIPs, but we loose probably in spatial resolution)

We are setting up a LASER system in laboratory for detailed tests


Upgrade: saturation effect2nd level upgradeTo reduce the saturation effect for high energy releases in silicon layers there are several possibilities that are under discussion and investigation. Decision are not yet fixed. Main points are:• No possibility to change the Pace3 chips with higher dynamic range

preamplifiers• We should operate directly on the silicon side

1. Reducing the silicon depleted thickness to produce less chargea. Decreasing the bias voltage (not safe)b. Producing new thin silicon detectors (safer but we loose the

possibility to detect MIPs)2. Reducing the charge collected by the readout strips

a. Connecting the floating strips to ground (we save the sensitivity to MIPs, but we have to study how much we loose in spatial resolution)

We are setting up a LASER system in laboratory for detailed tests


Upgrade: saturation effect (2)

FloatingFloatingFloatingFloating

GNDGNDGNDGND

The charge collected on the floating strip is collected by capacitive coupling on the read out strip

The charge collected on the grounded strip is definitely lost!We reduce the collected charge.We can also do more complex geometries:Readout-Gnd-Gnd

The existing situation

Under investigation


Upgrade: saturation effect (3)Silicon sensor Fan-out circuits

Basic detection unitModifications:New fan-out circuitsNew bonding schemeNew thin silicon layers


Upgrade: energy resolution

Our main idea:

• Do not increase the number of silicon layers

• Re-arrange the position of the existing 8 silicon layers inside

the calorimeter, to make better use of the 4 silicon sensors

currently located very deep in the calorimeter and not useful

for energy measurement

• Keep anyway few ‘double layers’ to have a good matching

between x and y coordinates


Upgrade: energy resolution (2)

Geometrical configuration of this simulation study

Silicon layers are inserted at the front of all scintillator layers.For energy reconstruction, Summation of dE of all scintillator layers,2, 8 and 16 of the 16 silicon layers.

Silicon layer positions in the current Arm2 detector.

X,Y X,Y X,Y X,Y

X Y X Y X Y X Y

Distribute 8 silicon layers

Optimization of silicon layer positions for energy reconstruction


Upgrade: energy resolution (3)

Good energy resolution of the silicon layers !!

Hit Position Selection

4<x<16,4<y<16

8 Silicon Layers 6 6 12 12 18 26 34 42 X0

Simulation implemented with the FLUKA simulation tool


Upgrade: energy resolution (4)Original configuration

Updated configuration

double layers(2X0 thick tiles)


SummaryLHCf has published the single photon spectrum in two different pseudo-rapidity intervals in the very forward region of the LHC for 7 TeV total energy pp interactions. New analysis are under development for the study of neutrons and neutral pions and for the transverse momentum distributions.Plan for the future measurements:1. Proton-lead run at LHC in 2012

Requires correction of pedestal fluctuation (test in lab with laser system) Simulation under development (3.5 TeV proton energy) Presentation of LOI at beginning of 2012

2. Proton-proton interactions at 14 TeV It is the main purpose of this experiment Reduction of saturation effect (test of possible solutions and production of new

silicon modules)

3. Study of a possible proton-light ion run at RHIC Simulations under development Visit at RHIC within end of 2011


Backup slides

The LHCf international collaborationO.Adriania,b, L.Bonechia, M.Bongia, G.Castellinia,b, R. D’Alessandroa,b, A.Fausn,

K.Fukatsuc, M.Haguenauere, Y.Itowc,d, K.Kasaharaf, K. Kawadec, D.Macinag, T.Masec, K.Masudac, Y. Matsubarac, H.Menjoa,d, G.Mitsukac, Y.Murakic,

M.Nakaif, K.Nodai, P.Papinia, A.-L.Perrotg, S.Ricciarinia, T.Sakoc,d, Y.Shimitsuf, K.Suzukic, T.Suzukif, K.Takic, T.Tamurah, S.Toriif, A.Tricomii,j, W.C.Turnerk,

J.Velascom, A.Viciania, K.Yoshidal

a) INFN Section of Florence, Italy b) University of Florence, Italyc) Solar-Terrestrial Environment Laboratory, Nagoya University, Japand) Kobayashi Maskawa Institute for the Origin of Particles and the Universe, Nagoya University,

Nagoya, Japane) Ecole Polytechnique, Palaiseau, Francef) RISE, Waseda University, Japang) CERN, Switzerlandh) Kanagawa University, Japani) INFN Section of Catania, Italyj) University of Catania, Italyk) LBNL, Berkeley, California, USAl) Shibaura Institute of Technology, Japanm) IFIC, Centro Mixto CSIC-UVEG, Spain

39

Open Issues on HECR spectrum

M NaganoNew Journal of Physics 11 (2009) 065012

Difference in the energy scale between different experiments???

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Data set for photon analysis ([email protected]+3.5TeV)• Data

– Date : 15 May 2010 17:45-21:23 (Fill Number : 1104) except runs during the VdM luminosity scan.

– Luminosity : (6.3-6.5)1028cm-2s-1,– DAQ Live Time : 85.7% for Arm1, 67.0% for Arm2– Integrated Luminosity : 0.68 nb-1 for Arm1, 0.53nb-1 for

Arm2 – Number of triggers : 2,916,496 events for Arm1

3,072,691 events for Arm2 – Detectors in nominal positions and normal gain

• Monte Carlo– QGSJET II-03, DPMJET 3.04, SYBILL 2.1, EPOS 1.99 and

PYTHIA 8.145: about 107 pp inelastic collisions each

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Luminosity• Luminosity for the analysis is calculated from Front Counter

rates:

• The conversion factor CF is estimated from luminosity measured during VdM scan

VDM scan

FC RCFL

Beam sizes sx and sy measured directly by LHCf

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Particle Identification (PID)

PID criteria based on transition curveL90% variable is the depth at which 90% of the signal has been released

MC/Data comparison done in many energy bins•QGSJET2-gamma and -hadron are normalized to data(/collision) independently• LPM effects are switched on

43

0 mass and energy scale issue (II)

Arm1 Data

• Disagreement in the peak position Peak at 145.8 0.1 MeV for ARM1 (7.8% shift) Peak at 140.0 0.1 MeV for ARM2 (3.8% shift)

• No ‘hand made correction’ is applied for safety• Main source of systematic error see later

Arm2 Data

Arm2 MC(QGSJET2)

Peak at 140.0 ± 0.1 MeV

Peak at 135.0 ± 0.2 MeV3.8 % shift

Many systematic checks have been done to understand the energy scale difference

7.8 % shift

Peak at 145.8 ± 0.1 MeV

3.8 % shift

44

Multiple hit (MHIT) event rejection (I)•Rejection of MHIT events is mandatory especially at high energy (> 2.5 TeV)

MHIT events are identified thanks to position sensitive layers in Arm1 (SciFi) and Arm2 (Si-strip)

One event with two hits in Arm2

One event with three hits in Arm2

45

Multiple hit (MHIT) event rejection (II)

Single detection efficiency for various MC models

Multi detection efficiency for various MC models

46

Acceptance cut for combined Arm1/Arm2 analysis

R1 = 5mmR2-1 = 35mmR2-2 = 42mm = 20o

For Small Tower > 10.94 For Large Tower 8.81 < < 8.99

For a comparison of the Arm1 and Arm2 reconstructed spectra wedefine in each tower a region of pseudo-rapidity and interval ofazimuth angle that is common both to Arm1 and Arm2.

As first result we present two spectra, one for each acceptance region, obtained by properly weighting the Arm1 and Arm2 spectra

47

Comparison Arm1/Arm2

Multi-hit rejection and PID correction applied.Energy scale systematic (correlated between Arm1 and Arm2) has not been plotted to verify the agreement between the two detectors within the non correlated uncertainties.

Deviation in small tower is still not clear. Anyway it is within systematic errors.

(small tower) (large tower)

48

Summary of systematics (I)

• Uncorrelated uncertainties between ARM1 and ARM2- Energy scale (except 0 shift) : 3.5%- Beam center position : 1 mm- PID : 5% for E<1.7TeV, 20% for E>1.7TeV

- Multi-hit selection :• Arm1 small tower: 1% for E<1TeV, 1%20% for E>1TeV• Arm1 large tower: 1% for E<2TeV, 1%30% for E>2TeV• Arm2 small tower: 0.2% for E<1.2TeV, 0.2%2.5% for E>1.2TeV• Arm2 large tower: 0.2% for E<1.2TeV, 0.2%4.8% for E>1.2TeV

• Correlated uncertainties- Energy scale (0 shift): 7.8% for Arm1 and 3.8% for Arm2 (asymmetric)

- Luminosity : 6.1%

Estimated for Arm1 and Arm2 by same methods but independently

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`

`

Summary of systematics (II)

Beam center position Multiple hit cut

`

Particle ID

More details in paper

Measurement of zero degree single photon energy spectra for √S=7TeV proton-proton collisions at LHCSubmitted to Physics Letters B

50

What do we expect from LHCf?

γ

nπ0

Energy spectra and transverse momentum distribution of • (E>100GeV, DE/E<5%)• Neutrons (E> few 100 GeV, DE/E30%)• 0 (E>500GeV, DE/E<3%)in the pseudo-rapidity range >8.4

51

Detector vertical position and acceptance • Remotely changed by a manipulator( with accuracy of 50 m)

Distance from neutral center Beam pipe aperture

Data taking modewith different positionto cover PT gap

N

L

G

All from IP

Viewed from IP

Neutral flux center

N

L

7TeV collisions

Collisions with a crossing angle lower the neutral flux center thus enlarging PT acceptance

52

Linearity of PMTs (Hamamatsu R7400)• PMTs R7400 are used in current LHCf system coupled to the

scintillator tiles• Test of linarity was held at HIMAC using Xe beam• PMT R7400 showed good linearity within 1% up to signal level

corresponding to 6TeV showerMAX in LHCf.

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Accumulated events in 2010

108 events! LHCf removal

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Pile-up eventsWhen the configuration of beams is 1x1 interacting bunches, the probability of N collisions per crossing is

The ratio of the pile up event is

The maximum luminosity per bunch during runs used for the analysis is 2.3x1028cm-2s-1

So the probability of pile up is estimated to be 7.2% with σ of 71.5mbTaking into account the calorimeter acceptance (~0.03) only 0.2% of events have multi-hit due to pile-up. It does not affect our results

55

0 mass versus 0 energy

Arm2 DataNo strong energy dependence of reconstructed mass

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2 invariant mass and mass

Arm2 detector: all runs with zero crossing angleTrue Mass: 547.9 MeVMC Reconstructed Mass peak: 548.5 ± 1.0 MeVData Reconstructed Mass peak: 562.2 ± 1.8 MeV (2.6% shift)

h candidate(50 events)

0 candidate

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Analysis of events @ 900 GeV

Event sample @ Arm1

Event sample @ Arm2

58

Beam-gas backgroud @ 900 GeV2009 2010

Very big reduction in the Beam Gas contribution!!!!Beam gas I, while interactions I2

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Beam test @ SPSEnergy Resolution for electrons with 20mm cal.

Position Resolution (Scifi)

Position Resolution (Silicon)

Detector

p,e-,mu

σ=172μmfor 200GeVelectrons σ=40μm

for 200GeVelectrons

- Electrons 50GeV/c – 200GeV/c- Muons 150GeV/c- Protons 150GeV/c, 350GeV/c

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Energy reconstruction @ SPSDifference of energy reconstruction at SPS between data and MC is < 1%.Systematic error for gain calibration factor layer by layer is 2%

61

Particle and energy flow vs rapidity

Multiplicity@14TeV Energy Flux @14TeV

Low multiplicity !! High energy flux !!

simulated by DPMJET3

62

Radiation damage

30 kGy

• Expected dose: 100 Gy/day at 1030 cm-2s-1

• Fewmonths @ 1030 cm-2s-1: 10 kGy• 50% light output• Continous monitor and calibrationwith

Laser system!!!

Scintillating fibers and scintillators

1 kGy63

Uncertainty on the energy scale

• Two components:- Relatively well known: Detector response, SPS => 3.5%- Unknown: 0 mass => 7.8%, 3.8% for Arm1 and Arm2.

• Please note: • - 3.5% is symmetric around measured energy• - 7.8% (3.8%) are asymmetric, because of the 0 mass shift• - No ‘hand made’ correction is applied up to now for

safety• Total uncertainty is

-9.8% / +1.8% for Arm1 -6.6% / +2.2% for Arm2

Systematic Uncertainty on Spectra is estimated from difference between normal spectra and energy shifted spectra.

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Uncertainty on the beam center• Error of beam center position is estimated to be 1 mm from comparison between our results and the BPM results

• The systematic errors on spectra were estimated from the difference between spectra with 1 mm shift of acceptance cut area.

5% to 20% linear rise from 100 GeV to 3.6 TeV

Arm1 Results - true single gamma events

100 GeV<E<3.5 TeV : 5%

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Uncertainty from PID

Template fitting A: 1 degree of freedom: - Absolute normalization

Template fitting B: 3 degrees of freedom: - Absolute normalization - Shift of L90% distribution - Width of L90% distribution

Efficiency and purity are estimated with two different approaches

Hatched : dataRed : true-gammaBlue : true-hadronGreen : Red+Blue

Systematic error from PID areassumed: 5% for 100GeV < E < 1.7TeV 20% for E > 1.7TeV Both on small and large tower

Arm1

Hatched : data Red : true-gamma Blue : true-hadron Green : Red+Blue

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Uncertainty from Multiple Hit corrections

ARM1

ARM2

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lorenzo bonechi ( infn – firenze) on behalf of the lhcf collaboration

Documents

energy measurement

energy flux

total energy deposit

baridetectors measure

high energy cosmic ray

lhc7 tev

rad beam

physics data