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Identify hadrons with p T ≥ 10 GeV/c Inclusive measurement, particle yields, especially protons

GOALS of the VHMPID. Identify hadrons with p T ≥ 10 GeV/c Inclusive measurement, particle yields, especially protons Weak identification, i.e. Π ,K – protons can be enough. First HI collision ?. Start of LHC. Yesterday. HMPID TDR. Urs Wiedemann, HI Forum 10 February 2004.

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Identify hadrons with p T ≥ 10 GeV/c Inclusive measurement, particle yields, especially protons

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  1. GOALS of the VHMPID • Identify hadrons with pT ≥ 10 GeV/c • Inclusive measurement, particle yields, • especially protons • Weak identification, i.e. Π,K – protons • can be enough

  2. First HI collision ? Start of LHC Yesterday HMPID TDR Urs Wiedemann, HI Forum 10 February 2004

  3. Č Threshold counter ? THE VHMPID, UPGRADE or DOWNGRADE ? or TIC ? RICH ?

  4. Nice detector but the radiator is too long (1m for <6> photons)

  5. SIC TRANSIT GLORIA MUNDI

  6. IMPROVED TIC1 (XXL momentum) CaF2 IP C4F10 HMPID CsIphoto-cathode

  7. Quartz cut-off Data from the HADES RICH(NIM A 433 (1999) 201-206) Radiator thickness 36 to 65 cm,12 to 22 photons detected

  8. C4F10 radiator

  9. 1.5 m

  10. IMPROVED TIC2 (XXXL momentum) Window less ! CF4 (CH4) CF4 + CsI give 40 photons with 50 cm radiator ! (Nucl. Instrum. Methods Phys. Res., A 523 (2004) 345-354)

  11. CF4 transparent down to 110 nm !

  12. CF4 radiator But aging needs to be investigated if we want to get rid of the window

  13. “Amazingly, extremely rapid aging has been observed for pure CF4 and in Ar/CF4/O2(50:40:10) mixture, which were expected to have strong etching abilities.” “Finally, it should be noted, that most of the aging studies in the CF4/hydrocarbon mixtures, were performed by irradiating a small region of the wire under well controlled laboratory conditions. At the same time, several painful experiences with aging are known from the high energy experiments.” M.Danilov, L.Laptin, I.Tichomirov, M.Titov, Yu.Zaitsev Aging tests of the proportional wire chambers using Ar/CF4/CH4(74:20:6), Ar/CF4/CH4(67:30:3) and Ar/CF4/CO2(65:30:5) mixtures for the HERA-B Muon Detector Moscow 2000

  14. We are here “In this article we present evidence that the rapid aging observed is related to chemical processes at the cathode rather than at the anode, as previously suggested.” J. Wise et al. J. Appl. Phys. 74 (Q), 1 November 1993

  15. A word of hope …

  16. Why not a GEM detector ? (perhaps with the ALTRO R/O) Nucl. Instrum. Methods Phys. Res., A 535 (2004) 324-329 Nucl. Instrum. Methods Phys. Res., A 523 (2004) 345-354 Much more challenging, a lot of R&D required

  17. TWO STAGES TIC Window less ! CF4 C4F10 CaF2 window

  18. C4F10 + CF4 radiators But Cherenkov angles are very similar !

  19. ~2m

  20. This will work but it would be too long and complicated C4F10 CF4

  21. TWO STAGES TIC Window less ! CF4 C4F10 CaF2 window

  22. First results from test beam 50 cm + 50 cm # of photons Total charge Rad #1 Rad #1+#2

  23. 50 cm + 50 cm ~ 10 cm Radiator #1 Radiator #2 ~3 cm ~2.5 cm

  24. DELAYED IDENTIFICATION CaF2 C4F10 / CF4 CF4 Run X days with C4F10 ,Y days with CF4

  25. CF4 5< p <16 NΠ,NK+p 16< p <30 NΠ+K,Np p > 30 NΠ+K+p C4F10 3< p <9 NΠ,NK+p 9< p <16 NΠ+K,Np p> 16 NΠ+K+p 9<p<16 NΠ, NK ,Np 16<p<30NΠ+K,Np • + Identification • Identification • Indirect identification • Cross-checked

  26. COST: ~700 kCHF (from RICH TDR)

  27. The HADES RICH

  28. A FERRARI for ALICE Window less ! CF4 C4F10 CaF2 window Aerogel detector Pad chamber, no CsI For n = 1.01 ptrh 1, 3.5, 7 GeV/c for Π, Kandp. If we could rejectΠwe would have thehigh pT triggerwe need !

  29. IMPID + VHMPID

  30. Why I don’t like aerogel Why aerogel does not work • Momentum range not appropriate • Poor photons yield low efficiency • Too sensitive to electron background • Too sensitive to noise • Too sensitive to spread in PMTs gain • Efficiency vs. track position • Particles traveling through the PMT • Very expensive

  31. OPEN QUESTIONS (no matter the technology) Single or double arm ? Acceptance Do we need a trigger? How to trigger ?

  32. Do we know what we do ? We identify protons by NOT seeing a signal Very dangerous ! How to convince people that what we DO NOT see it is the truth ?

  33. Time scale Construction can’t start before 2006 (not even prototype) No test beam at CERN before June 2006 Perfect time for simulation and build a strong physics case

  34. Conclusions • It is possible to extend the PID capability of • ALICE up to 30 GeV/c making use of presently • available technologies at reasonable cost in • a reasonable time. • Two radiators are very suitable. • Simulation is needed in order to choose and optimize • the detector layout. • Simulation is needed in order to define the physics target • and understand the physics requirements. • Laboratory tests are needed in order to investigate • the aging of CF4. Further work on this subject is incompatible with the present commitments of the (CERN) HMPID group.

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