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the VHMPID D etector Upgrade for ALICE experiment at LHC

the VHMPID D etector Upgrade for ALICE experiment at LHC. Jungyu Yi Pusan National University for the ALICE-VHMPID Collaboration The 4th Asian Triangle Heavy Ion Conference Pusan, Nov. 14-17,2012. Outline. What is the VHMPID ? VHMPID RICH detector Layout & Characteristics

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the VHMPID D etector Upgrade for ALICE experiment at LHC

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  1. the VHMPID Detector Upgradefor ALICE experiment at LHC Jungyu Yi Pusan National University for the ALICE-VHMPID Collaboration The 4th Asian Triangle Heavy Ion Conference Pusan, Nov. 14-17,2012

  2. Outline • What is the VHMPID ? • VHMPID RICH detector • Layout & Characteristics • Why VHMPID ? • From ALICE HMPID to VHMPID • High pT PID Comparison in ALICE • Physics Motivation • What is the challenge? • Studies for Gas Radiator • Pressurized Gas radiator • Transparency measurement • Integration in ALICE • How it works? • Beam test 2012 : performances / Result at PS,CERN • Summary & Outlook R&D of VHMPID - ATHIC 2012

  3. The VHMPID RICH detector • Very High Momentum Particle Identification Detector; Ring Imaging Cherenkov(RICH) Detector Cherenkov radiation Ring Imaging : Principle of Focusing RICH r = f θc n : refractive index f : focal length of mirror *RICH can identify the charged particle combined with detectors for momentum measurement. R&D of VHMPID - ATHIC 2012

  4. Layout & Characteristics • Fluorocarbon (C4F8O / C4F10) Gasfor Cherenkov Radiator • <n> ≈ 1.0014 at 175 nm, γth ≈ 18.9 • pressure 3.5 atm, 40°C • 50cm length volume • CsI photon-detector • with MIP position, avalanche detector : MWPC /GEM • Spherical Mirror • f = 50cm • carbon fiber substrate • Al + MgF2 coated for UV • window (CaF2 / Sapphire) • FEE – HMPID GASSIPLEX 3σ PID of π, K, p 5 GeV/c < p < 25 GeV/ctrack-by-track basis Simulated : π, K, p at p = 16 GeV/c R&D of VHMPID - ATHIC 2012

  5. From ALICE HMPID • C6F14 liquid radiator • <n> ≈ 1.292 • 3 sigma π/K/p , 1 < p <5 Gev/c VHMPID separation @ 2σ separation @ 3σ • C4F10 / C4F8O Gas radiator • 3.5 atm, <n> ≈ 1.0014 • 3σ π/K/p , 5< p<25 Gev/c R&D of VHMPID - ATHIC 2012

  6. PID for high pT : TPC rdE/dx and VHMPID • VHMPID • Track-by-track • 3σ π/K separation in high pT • Limited acceptance (maximum 30% of central barrel) • rdE/dx • Statistical, reachinghigh pT • Clean π sample • p/K separations are difficult • No kaon PID R&D of VHMPID - ATHIC 2012

  7. Physics Motivation with VHMPID • Jet characteristics in p-p and A-A collisions with Track - by - Track PID • Hadro-chemistry & PID-triggerd Jet anlaysis in pp collision • baryon fragmentation functions via protons and anti- protons in jets • charmonium production process via pidcharacteristics in subleading heavy quark jet. • quark vs gluon fragmentation by measuring hadro- chemistry in tagged jets. • Hadronization & Jet Quenching in Pb-Pbcollison • baryon enhancement at intermediate to high pT • Detailed mapping of gluon splitting process (energy loss in medium) via measurement of hadro-chemistry in tagged jets. • Medium modification of charmoniumproduction and gluon/quark fragmentation • Baryon/anti-baryon imbalance via momentum dependent p/anti-p measurement in tagged jets in medium R&D of VHMPID - ATHIC 2012

  8. Studies for Gas Radiator • Pressure dependence • refractive index • Cherenkov angle vs. momentum for Pressure • Higher pressure higher refractive index larger Cherenkov angle & better resolution for separation at lower momentum • We are focusing 5 GeV/c < p < 25 GeV/c R&D of VHMPID - ATHIC 2012

  9. Pressurized Gas System To keep the ‘Gas’ phase,We have to heat the radiator Heating ~ 40°C Detector Gas Rack C4F8O • heated & insulated, • Radiator tank • supply line • Detector vessel • gas rack [fig] Phase diagram curves for some fluorocarbon compounds. C4F8O gas radiator @ 3.5 atm T >36°C R&D of VHMPID - ATHIC 2012

  10. Transparency Measurement Optical properties in VHMPID On-line measurements/monitoringof gas radiator qualities are needed!! • Detector efficiency is sensitive to, • O2 , H2O and chemical contaminants. • Photon Transmittance in radiator,especially for UV light. Transparency = Sig. Ar / Ref. at C4F8O Sig. / Ref. at Ar R&D of VHMPID - ATHIC 2012

  11. Control System for Gas radiator Pressurized Gas Supply system Transparency Measurement system • H/W • PLC (Programmable Logic Controller) • Deutrium light source 2) • Monochromator2) : λ = 30~275 nm, σλ = 0.1 nm • T, P sensors • O2, H2O analyzer • H/W • PLC (Programmable Logic Controller) • Electric valves, flow meters, regulators • T, P sensors • O2, H2O analyzer • S/W • : ‘STEP7’ for PLC + Based on PVSS control panel1) http://j2eeps.cern.ch/wikis/display/EN/PVSS+Service http://www.mcphersoninc.com/spectrometers/vuvuvvis/model234302.htm R&D of VHMPID - ATHIC 2012

  12. Integration in ALICE on Stage1 • VHMPID + (DCaL) or PHOS system in 5 sector (20o each), 3 Stages • 30% central barrel acceptance • Stage 1 : 15% acceptance wrtTPC • Stage 2 : 25% acceptance wrtTPC • |η | < 0.5 : with full installation in Stage3  Jet fully contained • Radiator length 50 cm keeping basic performance Longitudinal cross section of VHMPID central module (proposed) R&D of VHMPID - ATHIC 2012

  13. Beam Test 2012 June (1) – Layout study *layout of variable gap chamber • Anode-Cathode gap test, • Geometrical constraints in ALICE • 0.8 mm vs. HMPID’s : 2.0 mm • Performance Test with • C6F14 liquid radiator (HMPID like) • 6GeV/c e+π beam (T10,PS) l = 3mm gapR 2mm gapY R&D of VHMPID - ATHIC 2012

  14. Test Performance/Result π- beam (p =6GeV/c), radiator thickness =3mm 1850V , CH4 gas for MWPC 4 sigma OFFLINE ZERO suppression Raw Clusters 0.8mm , small but good performance!! • Pad size = 4*8 mm2 (dx*dy) • # of pads = 960 = 60 * 16 (x*y) • 1 FEE (3 GASSIPLEXs) = 3*16 pads • 20 FEEs for test • 3 mm thickness radiator C6F14 R&D of VHMPID - ATHIC 2012

  15. 2012 Nov. : Pressurized Gas radiator Test • Beam (T10, PS, CERN) • e- , π- & K- contaminants • 1.5 GeV/c < p < 6 geV/c • Trigger • Long Cherenkov counter for momentum selection • 4 (2x2) scintillators+PMT : size 1x1 cm2 • Big scintillator +iron for Muon trigger • Radiator • C4F8O @ 3.5 atm, 40°C • 50cm length, tube vessel • Photon detector • Anode-Cathode gap : 1.5 mm • pad size : 8x 4 mm2 R&D of VHMPID - ATHIC 2012

  16. Test Performance/Result Test Performance Simulation with On-line Measured Transparency π- K- p= 6 GeV/c beam C4F8O at 3.5 atm Anode-cathode gap : 1.5 mm Peak on the “Kaon” expected!! R&D of VHMPID - ATHIC 2012

  17. Summary & Outlook • VHMPID Upgrade in ALICE • PID at high momentum :5 < p < 25 GeV/c • track-by-track basis • New regime of hard processes in proton-proton and heavy-ion collisions. • Challenges are on going ! with some harvests. • Pressurized gas radiator system • On-line Control system has installed • Transparency meter has installed and tested • Beam tests • Layout studies has done. • Pressurized gas (C4F8O) radiator has studied. • Pressurized Gas system & Vessel also works well. • Good Performance in UV regionwith CsI + MWPC. • Visible range photon detection test with MCP-PMT will be in December. • We are waiting the ALICE approval in March 2013 Unique measurements at LHC !! R&D of VHMPID - ATHIC 2012

  18. Collaboration Thank you!! R&D of VHMPID - ATHIC 2012

  19. Back up R&D of VHMPID - ATHIC 2012

  20. Nobel Prize in 1958 Cherenkov Radiation Neutral Atom photon energy per unit length ↑ Dipole charged particle Medium (radiator) R&D of VHMPID - ATHIC 2012

  21. ALICE PID Capabilities separation @ 3s separation @ 2s VHMPID R&D of VHMPID - ATHIC 2012

  22. Layout Optimization test • Radiator thickness : 3mm • Radiator Gap : gapR • 35, 45, 55, 65, 70 (mm) • Anode-Cathode pad Gap : gapY • 2.0, 1.6, 1.2, 0.8 (mm) • HV scan • 1600 ~ 2050V • Vmin. & Vmax. are related w/ gapY. • Beam Rate (Triggered particle/spill) • 10, 180, 380, 750 • Veto study • w/o, 5, 10, 20, 30, 40, 50 (μs) • Delay • 750 (ns) • 250, 500, 625, 800, 875, 1000 • 2000, 5000, 10000 l = 3mm gapR 2mm gapY R&D of VHMPID - ATHIC 2012

  23. Clusters and parameters fiducial 16 rows = 128 mm y MIP 4×8 mm2 x 60 columns = 240 mm parameters.list x_min. = 12.5x_max. = 16.5 y_min. = 4.5 y_max. = 8.5 r_min. = 3.0 r_max. = 7.0 *[cm] r_max. y_max. r_min. y_min. x_min. x_max. R&D of VHMPID - ATHIC 2012

  24. Abstract • The Very High Momentum Particle Identification (VHMPID) detector represents a possible upgrade for the ALICE experiment at LHC. It has been conceived to extend hadron identification on a track-by-track basis in 5 GeV/c < p < 25GeV/c momentum range. The VHMPID is a ring imaging Cherenkov detector with pressurized gaseous radiator coupled to CsI-based photon detector. We will present the detector development status and some results from the beam tests at PS, CERN. R&D of VHMPID - ATHIC 2012

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