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LHCf: il run con ioni (e i due nuovi risultati …)

LHCf: il run con ioni (e i due nuovi risultati …). Oscar Adriani. 3 Aprile 2012. Some historical remarks. LHCf expression of interest for proton/Lead 2012 run Presentation at the LPCC meeting on October 17 th , 2011 Contact with Atlas management

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LHCf: il run con ioni (e i due nuovi risultati …)

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  1. LHCf: il run con ioni(e i due nuovirisultati…) Oscar Adriani 3 Aprile 2012

  2. Some historical remarks • LHCf expression of interest for proton/Lead 2012 run • Presentation at the LPCC meeting on October 17th, 2011 • Contact with Atlas management • Letter of Intent submitted to LHCC on December 4th, 2011 • CERN-LHCC-2011-015/LHCC-I-021 04/12/2011 • Approved by LHCC in December 2011! • The Committee has independently verified the support of the ATLAS Collaboration, and recommends the acceptance of the Letter of Intent. • And formal approval by RB practically obtained in March 2012! • The plan for LHCf to run during proton-Pb run was agreed by the LHCC and endorsed by the Research Board

  3. Global LHCf physics program LHCf measurement for p-Pb interactions at 3.5TeV proton energy could be easily and finely integrated in the LHCf global campaign.

  4. What LHCf can measure in the p+Pb run (1)E, pT,  spectra of neutral particles “p-remnant side” “Pb-remnant side” 140 m 140 m p-beam Pb-beam • We are simulating protons with energy Ep= 3.5 TeV • Energy per nucleon for ion is • “Arm2” geometry considered on both sides of IP1 to study both p-remnant side and Pb-remnant side • No detector response introduced yet (only geometrical considerations and energy smearing) • Results are shown for DPMJET 3.0-5 and EPOS 1.99, 107events each

  5. Proton-remnant side - multiplicity Big tower Small tower  n

  6. Proton-remnant side – photon spectrum Small tower Big tower

  7. Proton-remnant side – neutron spectrum Small tower Big tower 35% ENERGY RESOLUTION IS CONSIDERED IN THESE PLOTS

  8. Proton remnant side – Invariant cross section for isolated g-rays

  9. 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 >8.4 Very important for CR Physics Phys. Rev. Lett. 97 (2006) 152302

  10. Proton-remnant side – p0 We can detect p0! Important tool for energy scale And also for models check…..

  11. Lead-remnant side – multiplicityPlease remind that EPOS does not consider Fermi motion and Nuclear Fragmentation Small tower Big tower  n

  12. Some estimations based on reasonable machine parameters…. • Considering machine/physics parameters: • Number of bunches, n = 590 (150 ns spacing) • Luminosity up to 1028cm-2s-1 • Interaction cross section 2 barn • PILE-UP effect • Around 310-3interactions per bunch crossing • 1% probability for one interaction in 500 ns (typical time for the development of signals from LHCf scintillators after 200 m cables from TAN to USA15) • Some not interacting bunches required for beam-gas subtraction • Beam gas first estimation indicate no problem • Beam Gas/Beam Beam = 3.10-4

  13. … and required statistics to complete the p/Pb physics run • Minimum required number of collision: Ncoll = 108(factor 10 more statistics wrt shown plots) • Integrated luminosity Lint = 50 mb-1 • 2106 single photons expected on p-remnant side • 35000 0 expected on same side • Assuming a pessimistic scenario with luminosity L = 1026 cm-2s-1 : • Minimum running time for physics t = 140 h (6 days)

  14. Once we have been approved…. >3 weeks of run 4days slot to install • We have to do the run!!!!! • Technical points: • Installation issues • Manpower for Installation, setup and data taking • Please note that Arm2 is ‘more italianthan japanese’…. • Money for missions (Sblocco SJ, see referee presentation) 

  15. Preparation for 2012 p-Pb run Pb IP1 IP2 IP8 Arm2 p • We have installed multi-pole connectors in tunnel (02/12) • We have checked that optical fibers are ok (not damaged by radiation) (02/12) • We are producing a new transportation frame for Arm2+electronics • 1-2 experts will stay at CERN from September for DAQ commissioning • One month of 24 hours per day shifts (minimum 8 persons at Cern for one month, few from Japan and few from Italy) • Big manpower is requested…. • Please note that Atlas ZDC have already been removed in February 2012, since new detectors are being produced. The hadronic part will be installed behind LHCf on Arm2 side, and em+had part on the other side • Sinergies between LHCf and Atlas are encouraged by LHCC We are working on it Arm2

  16. New configuration New base plate Lead block for balance Fixing the three sub-systems together

  17. A fast spot on 2 new analyses

  18. Measured 900 GeV single g spectrum Submitted to PLB

  19. LHCf 7TeV p0 analysis Type-II Type-I Type-I sM=3.7% 1 1 Type-II PTp0(GeV/c) 0 0 3500 Ep0(GeV) 0 0 Ep0(GeV) 3500

  20. Combined type-I p0pTspectra (invariant cross section) Sys+stat DPMJET 3.04 QGSJETII-03 SIBYLL 2.1 EPOS 1.99 PYTHIA 8.145 8.9<y<9.0 1 9.0<y<9.2 9.2<y<9.4 1/Nint Ed3N/dp3 10-4 0.6 0 PTp0(GeV/c) 10.0<y<11.0 9.4<y<9.6 9.6<y<10.0

  21. Recent Publication (2011-2012)

  22. On-going analysis activity and plan • On going activity • 7TeV hadron energy spectra gInelasticity • Italian main analysis task for the near future • Full analysis of single g (larger h, pT, invariant cross section) • Full analysis of p0 (Type-II p0) • Feed back to the models and air shower experiments • Future plans • Strange particles (Lgp0n, Ksg2p0(4g))

  23. Spares slides

  24. Combined type-I p0pT spectra

  25. Radiation hardness of GSO Dose rate=2 kGy/hour (≈1032cm-2s-1) Irradiated sample Not irradiated ref. sample １kGy K. Kawadeet al., JINST, 6, T09004, 2011 τ~4.2h recovery No decrease up to 1 MGy +20% increase over 1 kGy (τ=4.2h recovery) 2 kGy is expected for 350nb-1 @ 14TeV pp)

  26. Photons on the proton remnant side QGSJET II-04 SIBYLL 2.1 p-p p-N p-Pb All s 8.81<<8.99 >10.94 Courtesy of S. Ostapchenko Photon energy distrib. in different  intervals at sNN = 7 TeV Comparison of p-p / p-N / p-Pb Enhancement of suppression for heavier nuclei case

  27. Lead-remnant side – neutron spectrum Small tower Big tower 35% ENERGY RESOLUTION IS CONSIDERED IN THESE PLOTS

  28. GSO property(EJ260: plastic scintillator used in the current LHCf detectors) Heavy; reason to reduce 3->1mm Fast among inorganic scintillators Identical to the current scintillators Similar to the current scintillators Light collection may differ Best in the known scintillators

  29. Uniformity test using C beam at HIMAC(preliminary results from quick analysis) mm mm mm No particle due to the beam pipe PMT via fiber bundle • Scan examples for a 20mmx20mm and a 40mmx40mm GSO plates • All scintillators of Arm1 were mapped by C beam • Similar uniformity to the current detector is obtained mm PMT via fiber bundle

  30. GSO plate and light guide packed in a new holder New structure GSO bar bundle and quartz fiber light guide GSO plates and bars as calorimeters, but without Tungsten absorber layers

  31. GSO bars cross talk and attenuation No paint between bars 10% Irradiated bar (100%) -30%/35mm 0% Attenuation along the longest 40mm bar Cross talk Attenuation and cross talk are acceptable to determine the position of single particle shower and multihit identification For multihit analysis, further study is necessary Paint between the bars reduces cross talk, but worsens attenuation and its bar-to-bar variation

  32. Estimation of Beam Gas background • Input from p-p collisions (Data set used for the photon paper). • Luminosity per bunch (L/n) : 2x1028cm-2s-1/bunch • Intensity per bunch (I/n)  : 2x1010protons/bunch • Total detected events in 25mm tower at non-bunch crossing : 101 photon events (for non crossing bunches) • DAQ live time : ~ 8x103 sec • -> Event rate of beam gas per bunch = 101/8000/3 = 0.004 Hz • Inputs from p-Pb (assumptions) • Luminosity per bunches (L/n) : 1.7x1025cm-2s-1/bunch (L=1028, n=590) • Inelastic cross section  : 2 barn • Expected collision rate : 34 Hz • Expected photon detection rate in 25mm : 0.34 Hz (assuming acceptance=0.01) • Estimation of beam-gas background for p-Pb • Assuming as the optics for p-Pb is same as one for p-p (same beta, same emittance), the relative intensity is estimated by using L/n. • (I/n)pPb/ (I/n)pp~ 0.03 • The beam-gas background rate should be proportional to the intensity per bunc, so it is estimated as 0.03 x 0.004 Hz = 10-4Hz • As conclusion, the N/S in p-Pb is estimated as 10-4 / 0.34 = 3x10-4 Negligible!!!!

  33. Few details about the LHCf Arm2 detector Sampling and imaging E.M. calorimeter Performances Energy resolution (> 100 GeV): < 3% for 1 TeV photons and  30% for neutrons Position resolution for photons: 40μm (Arm#2) • Absorber: W (44 r.l , 1.55λI ) • Energy measurement: plastic scintillator tiles • 4 tracking layers for imaging:XY-Silicon strip(Arm#2) • Each detector has two calorimeter towers, which allow to reconstruct p0 Arm2 Front Counters 32mm • thin scintillators 80x80 mm2 • monitoring of beam condition • Van der Meer scan 25mm

  34. LHCf physics program for p-Pb run WHY • Precise measurement of of E,  and pT distributions for pseudo-rapidity  > 8.4 both for p and Pb remnant • Single g • Neutral pions • Neutrons HOW Important information for the study of the interactionof UHECR in the Earth atmosphere • Comparison with hadronic interaction models • Study of the Nuclear Modification Factor • Inelasticity

  35. Lead-remnant side – photon spectrum Small tower Big tower

  36. LHCf plans for the p/Pb run • We will run with only one detector • Arm2 (W/scint. e.m. calorimeter + m-strip silicon) • Only on one side of IP1 (on IP2 side, compatible with the preferred machine setup: Beam1=p, Beam2=Pb) • Minimal interference with Atlas • Installation during the technical shutdown at the end of the p/p 2012 run

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