1 / 25

COMPASS RICH-1 on behalf of the COMPASS RICH Group

COMPASS RICH-1 on behalf of the COMPASS RICH Group. Plan of the talk. COMPASS for pedestrians Rich-1 Parameters Detector Components Radiator Mirrors Quartz Windows Photon-Detectors Front-End electronics Performances in 2001-Run Conclusions and outlook. Nucleon structure

smertz
Download Presentation

COMPASS RICH-1 on behalf of the COMPASS RICH Group

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. COMPASSRICH-1on behalf of theCOMPASS RICH Group Andrea Bressan University-INFN Trieste

  2. Plan of the talk • COMPASS for pedestrians • Rich-1 Parameters • Detector Components • Radiator • Mirrors • Quartz Windows • Photon-Detectors • Front-End electronics • Performances in 2001-Run • Conclusions and outlook Andrea Bressan University-INFN Trieste

  3. Nucleon structure Gluon polarization G(x) Flavour-dependent helicity functions q(x) Transverse-spin distribution functions Tq(x) Spin-dependent fragmentation (Dq) Spectroscopy Primakov reactions Polarizability of  and K Glueballs and hybrids Charmed mesons and baryons Semileptonic decays HQET Observe double-charmed baryons COMPASS Program Andrea Bressan University-INFN Trieste

  4. DG Measurements • Single out gg fusion graphs • Heavy quark lines (cc) • High transverse momentum • Experimentally: • DIS + D0 (e.g. via p++K-) • DIS + D+* (p++D0) • DIS with high Pt hadrons • Asymmetries measure DG • A  D AgN ~ D Agg DG/G hadrons N(p) g g Andrea Bressan University-INFN Trieste

  5. Polarized  beams and polarized nucleon targets hadron beams (up to 300 GeV energy) COMPASS Experiment Complex apparatus to allow a wide range of measurements Large dynamical range (angles and momenta) Particle identification High-rate capabilities Andrea Bressan University-INFN Trieste

  6. 2001 Apparatus Muon Wall Spectrometer Magnet 1 +tracking Calorimetry Polarised Target Spectrometer Magnet 2 Muon Wall Calorimetry-1 RICH1 SPS 160 GeV m beam Andrea Bressan University-INFN Trieste

  7. RICH-1 Parameters Main requests from the experiment: • /K separation up to ~ 60 GeV/c • Large angular acceptance: 250mrad 200mrad (V) • Minimize materials Design: • Radiator: C4F10, length: ~ 3m • Mirrors: • Spherical, focal length 3.3 m • Reflectance > 80% for  > 165nm • Total surface • Photon detectors: MWPC’s with CsI photocathodes, out of acceptance / total surface 5.3 m2 • Read-out electronics: • Analog read-out/ 83 K channels • average occupancy 5% • max data rate 2.5 Gb/sec in spill Material Budget: • Total 22.5% of X0 • Mirrors 5.5% • Radiator 10.5% Andrea Bressan University-INFN Trieste

  8. Measured Parameters Contribution to n Andrea Bressan University-INFN Trieste

  9. VESSEL Excellent Gas Tightness of the Vessel 10 ppm Contamination of O2 at 4m3/h 0.2 l/h at 1 mbar overpressure O2 H2O Andrea Bressan University-INFN Trieste

  10. 2001 Mirror Mounting Dedicated talk: S. Costa, ”The mirror system of COMPASS RICH-1” Andrea Bressan University-INFN Trieste

  11. Mirror Wall-Checks 2000 = immediately after coating • reflectance of 2 test mirrors measured after 2 year in RICH-1 vessel: • No degradation above 165 nm mirror n. 2 2000 reflectivity 2001 2002 wave length mirror n. 5 2000 reflectivity 2001 2002 wave length Andrea Bressan University-INFN Trieste

  12. C4F10 Gas RADIATOR Dedicated talk: P. Fauland, ”The radiator gas and the gas system of COMPASS RICH-1” pre-cleaning material loss: ~7% • C4F10pre-cleaning (in liquid phase) and on-line monitoring of VUV light transmission • measured through 5 cm of liquid (~ 7 m of gas, 1 bar) scaled to 5 m of gas (mean photon path in vessel) • In 2001 radiator gas was a mixture C4F10 : N2 = 50 : 50 pre-cleaning material loss: up to 50% Andrea Bressan University-INFN Trieste

  13. RADIATOR GAS, 2002 MATERIAL • new C4F10 delivery, 570 Kg • better quality, • polluting contamination: mainly water • new pre-cleaning installation: cleaning in gas phase raw material Andrea Bressan University-INFN Trieste

  14. Photon Detectors Basic Design from RD26 Andrea Bressan University-INFN Trieste

  15. Quartz Window Andrea Bressan University-INFN Trieste

  16. Problems with PDs • PDs electrical instability at high beam rate • (6 over 8 PDs operated at 100-150 V lower than the 2100 V nominal HV) • Actions taken: • hunting the technical problem: local wire defects • 4 refurbished wire planes • 2 new wire planes (wire LUMAMETALLOSRAM) • Status: PDs mounted again on RICH-1 vessel Setup for anode wire alignment and soldering wire defect, diameter 20 mm Detected Spark Andrea Bressan University-INFN Trieste

  17. Photon Detector Mounting CsI Deposit on PCB Final Installation PCB Transport System Photon Detector Mounting PCB Mounting Andrea Bressan University-INFN Trieste

  18. RICH-1 – READ-OUT Dedicated talk: M.L. Crespo, ”The COMPASS RICH-1 Read-Out System” • analogic read-out system, 84,000 channels with local intelligence (DSP, FPGA in FE BORA board) working • dead time: limited to 500 ns / event up to trigger rates of 75 KHz • average noise level: ~ 2000 e- , non homogeneous (2001) • reinforced ground lines (2002), noise level: ~ 1100 e- PC resident control board DOLINA Front End BORA boards mounted on photon detector Andrea Bressan University-INFN Trieste

  19. Noise Reduction Noise sigma for each pad 2001 Run The shape of the PCB support Is reproduced Noise sigma for each pad 2002 Run The shape of the PCB support Absent Run 2001 s=2100 e- Run 2002 s=1100 e- Sigma Andrea Bressan University-INFN Trieste

  20. 2001 Data Analysis Abrided from the Dedicated Poster: P. Schiavon et al, ”RICHONE: a software package for the reduction of COMPASS RICH-1 data” Andrea Bressan University-INFN Trieste

  21. Integrated EVENTS Photon detector (Up) Beam halo Photon detector (Down) Andrea Bressan University-INFN Trieste

  22. Reconstructed RING “Ring event” The cross indicates the track “image ” The blue dots are the pads The black dots are the selected clusters Andrea Bressan University-INFN Trieste

  23. Cherenkov ANGLE • Cherenkov angle of photons of the Rich • Cherenkov angle of the ring for > 60 GeV particles Superimposed (yellow) out of time signals (a) b = 1 (b) all b Qphotons Qring Andrea Bressan University-INFN Trieste

  24. Number of Photons • Cherenkov angle of Reconstructed Ring • Number of Photons of the Reconstructed Ring Superimposed (yellow) out of time signals all b (a) (b) all b Qring Nphotns 11.7 photons 13.0 photons Andrea Bressan University-INFN Trieste

  25. Conclusions and Outlook 2001 Run: • All important staffs on the floor  • 50% of Radiator Gas in  • Front End electronics working satisfactory  • Noise figure higher than expected  • Electrical Instabilities from PDs  2002 Run: New Staffs • Cooling system for the front-end electronics • Fast Radiator Gas mixing in the vessel • Improved noise • Refurbished and rewired PDs • Full radiator GAS 2002 Run: Still Missing Staffs • Vessel thermalisation Andrea Bressan University-INFN Trieste

More Related