lhcf status oscar adriani csn1,milano, 26 marzo 2013
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LHCf StatusOscar Adriani
CSN1,MIlano, 26 Marzo 2013
Summary of operations in end 2012- beginning 2013 (after the Torino meeting)
Arm2 has been re-installed in the TAN region in December 2012
January-February 2013: p/Pb run
Arm2 will be removed from the TAN in April 2013
The Arm2 upgrade for the 13 TeV run will be done in Florence in 2013 in strict collaboration with Japanese colleagues
Some more details will be given in the next slides
Re-Installation issues
Arm2 has been successfully re-installed in the TAN during the technical stop foreseen at the end of the p/p run December 18th
We have modified the LHCf support structure and cabling to significantly reduce the installation required time
Mechanical survey has been done in 2 steps: Internal LHCf survey on ground LHCf survey wrt to LHC: done on December 18th in the
TAN area
No big problem of radiation, the installation was completely safe (Thanks to Raffaello and Sako!!!)
Discussions and agreements with ATLAS (I)
ATLAS trigger can not be sent to LHCf due to timing problem
LHCf Level1 Trigger signal has been sent to ATLAS for the whole p/Pb running period
ATLAS has properly prescaled the LHCf trigger signal Prescaling factor depend on the running conditions
LHCf has recorded in the data stream all the counters and has used all the signals necessary to off-line identify the common events Event Counter Reset Atlas L1ID Bunch ID
Discussions and agreements with ATLAS (II)
Proton remnant side – Invariant cross section for isolated g-raysUsing only the LHCf informations
What happens if know the Impact Parameter?
Ideal case, assuming that we can precisely know the Impact Parameter b (in fm) on event by event basis
What happens if know the Impact Parameter?
What happens if know the Impact Parameter?
What happens if know the Impact Parameter?
What happens if know the Impact Parameter?
Combination of different impact parameter bins
In real li
fe b should be esti
mated by
using th
e Atlas i
nformatio
n (centra
lity)
The difference betw
een models
is
enhanced by th
e knowledge of the
impact
parameter
What happens with LHCf on Pb remnant side?
Nominal vertical position (Dy=0 cm)
Shifting up by y= +2.5 cm
The small calorimeter tower remain in the region not screened by the narrow elliptical shape of the beam pipe at D1 magnet We can take good data with reasonable number of hits!
LHCf operation in p – Pb runs at √sNN= 5 TeV
Pb
p
IP8IP2IP1
Arm2
p
Pb
IP8IP2IP1
Arm2
Proton remnant side
Lead remnant side
LHCf operation in p – Pb runs at √sNN= 5 TeV
#Eve
nts
(Mill
ions
)
p-remnant side
Pb-remnant side
Beam reversal
20 Jan 27 Jan. 01 Feb.
200 Millions triggered events!!!!
Summary of LHCf p-Pb runs
L = 0.5x1029 – 1x1029cm-2s-1
b* =0.8m, 145mrad crossing angle Not good for LHCf…. We didn’t succeed to get a dedicated high b* run due to
the lack of time
338p+338Pb bunches (min.DT=200ns), 296 colliding at IP1
10-20kHz trig rate downscaled to ~700Hz
20-40Hz ATLAS common trig Coincidence operation was successful!!!
Data both at p-side (20Jan-1Feb) and Pb-side (1fill, 4Feb)
Operation at Pb-remnant side
A high multiplicity event (Pb-side)
p
Pb
IP8IP2IP1
Arm2
MC (Pb-remnant)
3.5cm, 4.0cm
Proton-Proton Collision at √s = 2.76 TeV
We also profited of the ‘calibration’ run at √s = 2.76 TeV that has been done following the ATLAS and CMS requests
4 hours operation on 14 Feb. 2013 successfully done.
These data will allow a better study of the energy Scaling by comparing different c.m. energy (0.9 TeV, 2.76 TeV, 7 TeV, 13 TeV)
Data list of LHCf
p-p, √s=900GeV, 2010
✔ (event flags)
p-p, √s=2.76TeV, 2013
✔ LHCf triggers
p-p, √s=7TeV, 2010 ✔ ✔ (event flags)
p-p, √s=13 TeV, (2015)
✔ ✔ LHCf triggers
p-N,O, (>2019) ✔ ✔ LHCf triggers
p-Pb, √sNN=5TeV, 2013
✔ ✔ LHCf triggers
p-p 400GeV, p-Aat RHICH (???)
✔ ✔ PHENIX, STAR
γ, n π0
With ATLAS
Orange:Future operations
Black:completed operations
xF = E/E0
Playing a game with air shower development:effect of forward meson spectra
• DPMJET3 always overpredicts production• Filtering DPMJET3 mesons
• according to an empirical probability function, divide mesons into two with keeping pT
• Fraction of mesons escape out of LHCf acceptance
• This process• Holds cross section• Holds elasticity/inelasticity• Holds energy conservation• Changes multiplicity• Does not conserve charge event-by-event
E=E1+E2
E1E
2
xF = E/E0
pT
An example of filtering
π0 spectrum
photon spectrum
DPMJET3+filter
2.5x1016 eV proton
~30g/cm2
Apart from this ‘game’ we are in strict contacts with model developers to help them improving their codes.Few dedicated workshops have been organized to put theorists and experimentalists in contact
π0 spectrum and air shower
Vertical Depth (g/cm2)
AUGER, ICRC 2011
100 g/cm2
30 g/cm2
Other analyses and future activities….
Joint analysis with ATLAS … data ready
14 TeV p-p in 2015 … detector upgrade on going
Neutron spectra in 7TeV p-p … analysis on going
Light nuclei at LHC, RHIC???
… possibility in discussion
LHCf preparation for the 14 TeV p-p run
Calorimeter radiation hardening by replacing plastic scintillator with GSO
Production and laboratory tests of the new scintillators in Japan is finished for Arm1 and in progress for Arm2
Beam test at Ion facility (HIMAC) for Arm1 has been done in June 2012
Arm1 has been re-assembled in Florence starting from end of June 2012
Same procedure will be followed in 2013 for the Arm2 detector
Upgrade of the silicon positioning measurement system Rearranging Silicon layers for independent precise energy measurement Increase the dynamic range to reduce saturation effects
Test Beam at LNS for the absolute energy calibration of the silicon system is being requested
Why neutron measurement is important for CR physics
Auger hybrid analysis• event-by-event MC
selection to fit FD data (top plot)
• comparison with SD data vs MC (bottom plot)
• Clear muon excess in data even for Fe primary MC
The number of muons increases with the increase of the number of baryons! => importance of direct baryon measurement
Neutron Spectra at 7 TeV pp (models)
Model predictions
Model predictions smeared taking into account the LHCf energy resolution
Life is not easy…..
1 TeV neutrons simulated with 2 different hadronic interaction models used in the detector simulation
Other possibile future runs?
Possibility to use LIGHT IONS in LHC from 2016/2017? Light Ion source setup is ongoing because of SPS
interest RHIC run in 2015/2016 is under discussion… Please stand by a little bit to see how things are
evolving!!!!
Il calcolo per LHCf A settembre la CSN1 ci ha ‘suggerito’ di muoversi nella
direzione di utilizzare le risorse di calcolo del CNAF (nonostante le richieste estremamente limitate di 15 kEuro)
In questi mesi, con l’aiuto di Vincenzo Vagnoni e con il supporto di Luca Dell’Agnello, abbiamo sistemato le infrastrutture tecniche necessarie per: Generazione (per almeno 4 modelli di interazione adronica) End2End (trasporto beam-pipe) DoubleArm (simulazione del rivelatore)
Compilatori, spazio di storage, creazione degli account e delle code per I jobs, etc.
Il sistema ora e’ ‘pronto per partire’
Necessita’
Almeno 4x107 eventi Generazione:
35 kB/event 0.1 sec/event
Trasporto: 100-500 kB/event 100-500 sec/event
Simulazione: 20 kB/event 10 sec/event
CPU:
Almeno 4x109 secondi estendibili a 1.3x1010 sec se ci fosse la necessità di avere 108 eventi per un modello
Storage: 20-30 TB
Come sta andando
Siamo in contatto con CNAF per finire di risolvere i problemi tecnici rimasti
La procedura e’ stata faticosa, ma alla fine siamo (quasi) arrivati….
Non mi e’ chiaro come ora sia necessario procedere con la commissione per pagare le risorse CNAF….
Conclusions
Re-installation in the tunnel and p/Pb run went very smooth
p/Pb and neutron analyses are on-going Atlas joint analysis is ready to start Arm2 upgrade will be completed in 2013 Computing system at CNAF is available Ready to take data at 14 TeV And…. Possible Light Ions runs at RHIC/LHC are under
investigation
Next week we will have the LHCf meeting in Nagoya
Spares slides
Miscellanea IV: LHCf computing
Lo scorso anno abbiamo presentato un piccolo modello di calcolo per far fronte alle esigenze di simulazione e ricostruzione di LHCf per il run p-Pb di cui siamo responsabili I referee ci hanno finanziato una parte di quello richiesto rimandando a
quest’anno la seconda parte a fronte di stime più precise per consentirci la produzione dei plot per la LOI
Il data set per la LOI è stato prodotto interamente in Italia e le tre macchine acquistate sono state fondamentali
Abbiamo fatto i primi test di simulazione completa con p-Pb 500 KB per evento e 570 sec/evento con la simulazione completa 20 KB per evento e 22 sec/evento se applichiamo dei tagli cinematici abbastanza
duri (eccessivi per quello che vorremmo fare) Una via di mezzo tra queste due, dell'ordine dei 100 KB e 100 sec/evento e' quella
piu' realistica senza perdere informazioni di fisica rilevanti.
Noi abbiamo bisogno di produrre come minimo 107 eventi per ciascuno dei modelli studiati (finora 5)
Poichè le stime dello scorso anno, basate sulla sola generazione erano ben più ottimistiche di quello che abbiamo ottenuto ora, chiediamo il completamento delle risorse. Per il disco cercheremo di utilizzare risorse presenti in sezione ma abbiamo bisogno di CPU dedicate 15 Keuro per l’acquisto delle CPU
Radiation hardness of GSO
No decrease up to 1 MGy
+20% increase over 1 kGy (τ=4.2h recovery)
2 kGy is expected for 350nb-1 @ 14TeV pp)
1 kGyNot irradiated ref. sample
Irradiated sample
τ~4.2h recovery
K. Kawade et al., JINST, 6, T09004, 2011
Dose rate=2 kGy/hour(≈1032cm-2s-1)
Proton-remnant side – photon spectrum
Small tower Big tower
Proton-remnant side – neutron spectrum
Small tower Big tower
35% ENERGY RESOLUTION IS CONSIDERED IN THESE PLOTS
What LHCf can measure in the p+Pb run (2)Study of the Nuclear Modification Factor
Nuclear Modification Factor measured at RHIC (production of p0): strong suppression for small pt at <>=4.
LHCf can extend the measurement at higher energy and for >8.4Very important for CR Physics
Phys. Rev. Lett. 97 (2006) 152302
Lead-remnant side – multiplicityPlease remind that EPOS does not consider Fermi motion and Nuclear Fragmentation
n
Small tower Big tower
π0 results: Data vs MC
π0 results: Data/MCSubmitted to PRD (arXiv:1205.4578).
<pT> distribution
Three different approaches used to derive the average transverse momentum, ⟨pT⟩1. by fitting an empirical function
to the pT spectra in each rapidity range (exponential distribution based on a thermodynamical approach)
2. By fitting a gaussian distribution
3. by simply numerically integrating the pT spectra
Results of the three methods are in agreement and are compared with UA7 data and hadronic model predictions.
Two UA7 and LHCf experimental data show the same trend→ no evident dependence of <pT> on ECMS.
YBeam=6.5 for SPSYBeam=8.92 for7 TeV LHC
Comparison wrt MC Models at 900 GeV
small-η
= La
rge to
wer
big-η =Small tower
A jump back to g analysis: Comparison btw 900GeV and 7TeV spectra
Normalized by the number of entries in XF > 0.1 No systematic error is considered in both collision
energies.
XF spectra : 900GeV data vs. 7TeV data
Good agreement of XF spectrum shape between 900 GeV and 7 TeV. weak dependence of <pT> on ECMS
Preliminary
Data 2010 at √s=900GeV(Normalized by the number of entries in XF > 0.1)Data 2010 at √s=7TeV (η>10.94)
Coverage of the photon spectra in the plane Feynman-X vs PT
900GeV vs. 7TeVwith the same PT region
900 GeV Small+large tower
Neutron Detection Efficiency and energy linearity
Efficiency at the offline shower triggerFlat efficiency >500GeV
%
Linear fitParabolic fit
Energy and Position Resolution
X Y
Neutron incident at (X,Y) = (8.5mm, 11.5mm) ~1mm position resolutionWeak dependence on incident energy
We are trying to improve the energy resolution by looking at the ‘electromagneticity’ of the event
K0 analysis
K0 Acceptance
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