CRIS 2008 - Cosmic Ray International Seminar Origin, Mass Composition and Acceleration Mechanisms of...

CRIS 2008 - Cosmic Ray International Seminar

Origin, Mass Composition and Acceleration Mechanisms of UHECRs

Malfa, Salina Island,Eolian Islands, Italy, September 15 - 19 ,

2008

Raffaello D’Alessandro Università & INFN - Firenze 1

CRIS 2008 - Malfa, Salina Island,September 15 - 19 , 2008

Raffaello D’Alessandro Università & INFN - Firenze

CRIS 2008 - Malfa, Salina Island,September 15 - 19 , 2008 2

Compared to the usual HEP ones.Mainly a Japanese – Italian endeavor.

CERND.Macina, A.L. PerrotUSALBNL Berkeley:W. TurnerFRANCEEcole Politechnique Paris:M. HaguenauerSPAINIFIC Valencia: A.Fauss, J.Velasco

JAPAN:STE Laboratory Nagoya University:K.Fukui,Y.Itow, T.Mase, K.Masuda,Y.Matsubara, H.Menjo,T.Sako, K.Taki, H. WatanabeWaseda University: K. Kasahara, M. Mizuishi, Y.Shimizu, S.ToriiKonan University: Y.MurakiKanagawa University Yokohama: T.TamuraShibaura Institute of Technology: K. Yoshida



Energy and composition, two of the main issues that concern cosmic ray physics

today.

Astrophysical parameters - source type - source distribution - source spectrum - source composition - propagation

From LHC:Nuclear Interaction - Monte Carlo used for shower simulationsForward Physics - cross section - particle spectra (E, PT, θ, η, XF)



Events have been observed by the AGASA collaboration which upset our understanding of the physics

at the GZK cutoff.

GZK cutoff: 10GZK cutoff: 102020 eV eV

pp(2.7K)(2.7K)NN



The details at the tail of the spectra.

Berezinsky 2007Berezinsky 2007

AGASA x 0.9HiRes x1.2Yakutsk x 0.75Auger x1.2 (insufficient)

AGASA SystematicsTotal ±18%Hadron interaction (QGSJET, SIBYLL) ~10% (Takeda et al., 2003)



Also an issue with cosmic ray compositionIR

ONIR

ON

PROTON

PROTON

Knapp et al., 2003Knapp et al., 2003

Plotting the air-shower maximum vs. the energy, gives indication on the primary composition.



Xmax vs. anisotropy.

Favours iron.

Do you accept AGN correlation ?

Favours proton.



Very simulation dependent. Very different results, depending on models and input parameters

(KASKADE RESULTS).



Composition: inferred from Xmax

Energy Spectrum: inferred from the number of secondaries.

The dominant contribution to the The dominant contribution to the energy flux is in the energy flux is in the very forward region very forward region

( ( 0). 0).

Simulation of an atmospheric Simulation of an atmospheric shower due to a 10shower due to a 101919 eV proton. eV proton.

No cutNo cut: X: XFF<0.05<0.05, , K: XK: XFF<0.1<0.1XXF F Feynman var.Feynman var.



In this forward region the highest energy In this forward region the highest energy available measurements oft he available measurements oft he 00 cross cross

section were done by UA7 (E=10section were done by UA7 (E=101414 eV, y= eV, y= 5÷7)5÷7)

LHCLHC

TevatronTevatron

A 100 PeV fixed-target interaction A 100 PeV fixed-target interaction with air has the cm energy of a with air has the cm energy of a pp collision at the LHCpp collision at the LHC

AUGERAUGER

Cosmic ray spectrumCosmic ray spectrum

LHCf first proposed using LHCf first proposed using LHC, the highest energy LHC, the highest energy accelerator availableaccelerator available(14 TeV E(14 TeV ECMCM equiv. to equiv. to EElablab=10=101717 eV ) eV )

to calibrate MC simulation to calibrate MC simulation codecode



Placed after the beam pipes split.

Reaches down to θ=0.

Detectors installed in the TAN Detectors installed in the TAN region, 140 m away from the region, 140 m away from the Interaction Point, in front of Interaction Point, in front of luminosity monitors.luminosity monitors.



In the end, it was decided to put it around interaction point 1. ATLAS.

LHC



Detectors should measure energy Detectors should measure energy and position of and position of from from 00 decays decays

e.m. calorimeters with position e.m. calorimeters with position sensitive layerssensitive layers

INTERACTION POINTINTERACTION POINT

IP1 (ATLAS)IP1 (ATLAS)

Beam Beam lineline

Detector IIDetector II

TungstenTungsten

ScintillatorScintillator

Silicon Silicon stripsstrips

Detector IDetector I

TungstenTungsten

ScintillatorScintillator

Scintillating fibersScintillating fibers

140 m140 m 140 m140 m

Two independent detectors on both side of IP1Two independent detectors on both side of IP1 RedundancyRedundancy Background rejection (especially beam-gas)Background rejection (especially beam-gas)



2 towers 24 cm long stacked vertically with a 5 mm 2 towers 24 cm long stacked vertically with a 5 mm gapgap

Lower: 2 cm x 2 cm areaLower: 2 cm x 2 cm area

Upper: 4 cm x 4 cm areaUpper: 4 cm x 4 cm area

AbsorberAbsorber

22 tungsten layers 22 tungsten layers 7mm – 14 mm thick 7mm – 14 mm thick

(W: X(W: X00 = 3.5mm, R = 3.5mm, RMM = = 9mm)9mm)

16 scintillator layers 16 scintillator layers (3 mm thick) (3 mm thick)

Trigger and energy Trigger and energy profile profile

measurementsmeasurements

4 pairs of scintillating 4 pairs of scintillating fiber layers for tracking fiber layers for tracking purpose (6, 10, 32, purpose (6, 10, 32, 38 38 XX00.).)



2 towers 24 cm long stacked on their edges and 2 towers 24 cm long stacked on their edges and offset from one anotheroffset from one anotherLower: 2.5 cm x 2.5 cmLower: 2.5 cm x 2.5 cmUpper: 3.2 cm x 3.2 cmUpper: 3.2 cm x 3.2 cmAbsorberAbsorber

22 tungsten layers 22 tungsten layers 7mm – 14 mm thick 7mm – 14 mm thick

(W: X(W: X00 = 3.5mm, R = 3.5mm, RMM = = 9mm)9mm)

16 scintillator layers 16 scintillator layers (3 mm thick) (3 mm thick)

Trigger and energy Trigger and energy profile profile

measurementsmeasurements

4 pairs of silicon microstrip layers4 pairs of silicon microstrip layers (6, 10, 30, 42 (6, 10, 30, 42 XX00) for tracking ) for tracking purpose (X and Y directions)purpose (X and Y directions)



Japanese – Italian endeavour.Detector #1 assembled in Japan.Detector #2 assembled in Italy.

Arm#1 DetectorArm#1 Detector Arm#2 DetectorArm#2 Detector



Silicon modules and calorimeter briquettes.

LHCfLHCf

Luminosity Luminosity Monitor (BRAN)Monitor (BRAN)

ATLAS ZDCATLAS ZDCRaffaello D’Alessandro Università & INFN - Firenze


Installation performed in two phases:Installation performed in two phases:1.1. Pre-Installation (Jan/Apr 2007)Pre-Installation (Jan/Apr 2007) Baking out of the beam pipe (200 Baking out of the beam pipe (200

°C)°C)2.2. Final Installation (Jan 2008)Final Installation (Jan 2008)



1. Single photon spectrum2. 0 fully reconstructed (1 in each tower)

0 reconstruction is an important tool for energy calibration (0 mass constraint)

Basic concept: Minimum 2 towers (0 reconstruction)Smallest tower on the beam (multiple hits)Dimension of the tower Moliere radiusMaximum acceptance (given the LHC constraints)

Simulation is used to understand the physics performances

Beam tests in 2004, 2006 and 2007 Energy resolutionSpatial resolution of the tracking part

DPMJET3QGSJETQGSJETIISIBYLL

Used as ExamplesOf the models



Two tower geometry.LHC beam pipeLHC collimators

Detector #1Detector #2



Some runs with LHCf vertically shifted by few centimeters will allow us to cover the whole kinematical range.

Beam crossing Beam crossing angleangle



A vertical beam crossing angle > 0 will increase the acceptance of

LHCf



Monte Carlo 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 Quantitative discrimination with the discrimination with the help of a properly help of a properly defined defined 22 discriminating discriminating variable based on the variable based on the spectrum shape spectrum shape (see TDR for details)(see TDR for details)



Energy spectrum of π0 expected from different models

(Typical energy resolution for is 3 % at 1TeV)

0 geometrical acceptance



0 mass resolution

Arm #1E/E=5%200 m spatial resolution

m/m = 5%



Neutron energy distribution depends heavily on the model

adopted

Raw neutron energyRaw neutron energy 30% energy 30% energy resolutionresolution



PICCO, EPOSPICCO, EPOS

Drescher, Physical Review D77, 056003 Drescher, Physical Review D77, 056003 (2008)(2008)

NeutronNeutron

00

Trigger Trigger ScintillatorScintillator



• CERN : SPS T2 H4CERN : SPS T2 H4• 2004, 2006, 20072004, 2006, 2007• Incident ParticlesIncident Particles

•ProtonsProtons 150,350 GeV/c150,350 GeV/c•Electrons Electrons 100,200 GeV/c100,200 GeV/c•MuonsMuons 150 GeV/c150 GeV/c

• Final DetectorsFinal Detectors



Tests have been successfulTests have been successfulAnalysis is still ongoing Analysis is still ongoing

Energy calibration of the Energy calibration of the calorimeterscalorimetersSpatial resolution of the tracking Spatial resolution of the tracking

systemssystems

σx[m

m]

σｙ

[mm

]

Nu

mb

er o

f ev

ents

Nu

mb

er o

f ev

ents

σx=0.172[mm]

σy=0.159[mm]

x-pos[mm]

y-pos[mm] E[GeV]

E[GeV]

Detector #1 position resolution (Scintillating Fibers)



Implantation pitch 80.Read out pitch 160.

6, 10, 30, 42 Xo.

50 GeV electronX

0

4

2

3

0

10

6

200 GeV electron

X0

4

2

3

0

10

6



Alignment in progress, very preliminary results.

Silicon detector.

200 GeV electrons

σσxx=40 =40 mm

σσyy=64 =64 mm

Position Resolution X Side

0

20

40

60

80

100

120

0 50 100 150 200 250

Energy (GeV)

Re

so

luti

on

(m

icro

ns

)

Data

Simulation

Position Resolution Y Side

0

20

40

60

80

100

120

140

160

0 50 100 150 200 250

Energy (GeV)

Re

so

luti

on

(m

icro

ns

)

Data

Simulation



Energy with the silicon part only!200 GeV electrons.

E/E E/E ~~ 12% 12%

Energy Linearity with Silicon Sensors

y = 24,927x - 596,44

R2 = 0,994

0,00E+00

5,00E+02

1,00E+03

1,50E+03

2,00E+03

2,50E+03

3,00E+03

3,50E+03

4,00E+03

4,50E+03

5,00E+03

0 50 100 150 200 250

Energy (GeV)

En

erg

y M

ea

su

red

(a

.u.)

Data

Lineare (Data)



Energy resolution of the calorimeter.

Corrected for leakage.



Essential. We “invented” a special beam to test it.

>107 proton on target (special setting of the SPS )

9.15 m9.15 m

Carbon target (6 cm)Carbon target (6 cm)in the slot used for beam monitorin the slot used for beam monitor Detector #1Detector #1

Not in scale!Not in scale!

• Dedicated trigger on both towers of the calorimeter was used

• Main problems: – low photon energy (≥ 20 GeV) – Direct protons in the towers– Multi hits in the same tower

250 0 events were triggered (amidst background)

EEgammagamma=18GeV=18GeV

Shower Profile @ First SciFi Layer Shower Profile @ First SciFi Layer Calorimeters Calorimeters

20mm20mm

XX

40mm40mm

XX YY

YYEEgammagamma=46GeV=46GeV



PRELIMINARY!



•Phase-I• 900 GeV collision before ramping in 2008 (hope in a week from now!)• 10 TeV run in 2008 during the LHC commissioning (low luminosity)•14 TeV run in 2009 during commissioning •Remove LHCf when luminosity reaches 1030 cm-2s-1 for radiation damage reasons

•Phase-II•Re-install the detector at the next opportunity of low luminosity run •Dedicated runs (crossing angle, etc.)

•Phase-III•Future extension for p-A, A-A run with upgraded detectors are under study

Beam parameter

Value

# of bunches ≤ 43

Bunch separation

> 2 sec

Crossing angle

0 rad140 rad downward

Luminosity per bunch

< 2 x 1028 cm-2s-1

Luminosity < 1030 cm-2s-1

Bunch intensity

4x1010 ppb (*=18m)1x1010 ppb (*= 1m)



Beam Test in 2004/6/7:Full detector #1 & #2 tested

Installation already finishedARM1&ARM2 already successfully pre-installed in 2007Final installation successfully done in January 2008

Running conditions:Three foreseen phases

Phase I: first runs during LHC commissioning Phase II: parasitic mode during TOTEM run?Phase III: Heavy Ion runs?

Now we are waiting for the first collisions ....

And of course .............many sincere thanks to the organizers of this beautiful and extremely interesting conference.

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