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CMS Frascati

CMS Frascati

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CMS Frascati

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  1. CMS Frascati Stefano Bianco Laboratori Nazionali di Frascati dell’INFN S.Bianco CMS Frascati - LNF Scientific Committee

  2. OVERVIEW Where do we come from CMS and the RPC muon detectors Gas contaminants studies Gas gain monitoring system Physics analysis tasks Papers Conclusions S.Bianco CMS Frascati - LNF Scientific Committee

  3. Historical Touch (I) Our group forms in the 80’s with NA1 at CERN, then activity in FOCUS at Fermilab, LVD at G.Sasso, KLOE and FINUDA at LNF and finally BTeV at Fermilab. Previous experience in HEP detectors concentrated on calorimetry (NA1, FOCUS, KLOE) and strawtubes (FINUDA and BTeV). Traditional physics topics of interest in Heavy Flavours spectroscopy (FOCUS). Strong activity in FINUDA analysis (hypernuclear spectroscopy). S.Bianco CMS Frascati - LNF Scientific Committee

  4. Fixed frame Sliding frame Historical Touch (II) In BTeV our group conceived, proposed and developed the strawtube-microstrips integration in the forward tracker, introducing the novel solution of glued straws embedded in a Rohacell lattice without mechanical tension. We also introduced the Fiber Bragg Grating sensors technique in HEP, using them in FINUDA for the first time, and generalizing their use in BTeV for straws, microstrips and pixels. S.Bianco CMS Frascati - LNF Scientific Committee

  5. A small group with a tradition for HEP detectors design, construction and operation, and a strong motivation to physics analysis S.Bianco CMS Frascati - LNF Scientific Committee

  6. Historical Touch (III) • BTeV was canceled by US DOE in February 2005 • In April 2006 CMS Frascati was approved and funded by INFN S.Bianco CMS Frascati - LNF Scientific Committee

  7. CMS at the CERN LHChttp://cmsinfo.cern.ch/Welcome.html/ S.Bianco CMS Frascati - LNF Scientific Committee

  8. Resistive Plate Counter muon detector Gas mix used is 96.2% C2H2F4 / 3.5% Iso-C4H10 / 0.3% SF6 S.Bianco CMS Frascati - LNF Scientific Committee

  9. RPC muon detector S.Bianco CMS Frascati - LNF Scientific Committee

  10. CMS Frascati L.Benussia, M.Bertania, S.Biancoa, A.Brotzuc, M.A.Caponerob, D.Colonnac, D.Donisib, F.L.Fabbria, F.Fellic, M.Giardonia, B.Ortenzia, M.Pallottaa, A.Paolozzid, L.Passamontia, D.Pierluigia, A.Russoa, B.Ponzioa, C.Puccid, G.Savianoc aLaboratori Nazionali di Frascati dell’INFN, Italy bLaboratori Nazionali di Frascati dell’INFN and ENEA Frascati, Italy cLaboratori Nazionali di Frascati dell’INFN and Facolta’ di Ingegneria Roma1, Italy dLaboratori Nazionali di Frascati dell’INFN and Scuola di Ingegneria aerospaziale Roma 1, Italy In 2007: 7.5 FTE staff+PhD, 1.5 FTE technicians S.Bianco CMS Frascati - LNF Scientific Committee

  11. Tasks and Responsibilities in CMS • CMS Frascati was approved and • funded by INFN in April 2006. • Frascati Tasks: • Cabling coordination (D.Colonna) • QC at production site • Gas purity and material studies, Gas gain monitoring system (S.Bianco) • Analysis S.Bianco CMS Frascati - LNF Scientific Committee

  12. LNF located at ~80km from RPC production site S.Bianco CMS Frascati - LNF Scientific Committee

  13. Quality Control at General Tecnica (Colli, FR) S.Bianco CMS Frascati - LNF Scientific Committee

  14. GAS STUDIES • Resistive Plate Chambers (RPC) detectors are widely used in HEP experiments for muon detection and triggering at high-energy, high-luminosity hadron colliders, in astroparticle physics experiments for the detection of extended air showers, as well as in medical and imaging applications. • While gain and efficiency stability are always a must, in the case of RPC detectors in high-rate experiments which use freon-based gas mixtures, utmost care has to be paid also for the possible presence of gas contaminants. • The RPC detector of experiment CMS at the LHC proton collider (CERN, Switzerland) will employ a gas analysis and monitoring system for the online monitor of the freon-based gas mixture used. • The gas monitoring system is based on small RPC detectors whose working point (gain and efficiency) is continuously monitored online. The gas monitoring system is designed to provide fast and accurate determination of any shift in working point conditions. • Quantitative gas chemical analysis is then performed online by a complete system which includes gas-chromatography, pH sensors and contaminants (notably HF) detectors. S.Bianco CMS Frascati - LNF Scientific Committee

  15. THE CMS CLOSED LOOP GAS SYSTEM • Because of high cost and huge volumes of the Freon-based gas mix used, CMS will use a recirculation (Closed Loop) gas system developed by the CERN gas group. • The Closed Loop is a critical component of RPC. CMS has accumulated experience on its use and performances during the test at the Gamma Irradiation Facility at CERN in 2001, and currently at the ISR where chambers are tested in CL prior to installation. • At the GIF facility we observed substancial production of HF, linearly correlated with the signal current S.Bianco CMS Frascati - LNF Scientific Committee

  16. CLOSED LOOP GAS RECIRCULATION Purifiers are THE crucial component S.Bianco CMS Frascati - LNF Scientific Committee

  17. SEM image of a defect with two magnifications SEM-EDS STUDY OF IRRADIATED RPCs • We opened RPCs irradiated at the GIF and observed defects on the inner surfaces. Anode Cathode • We performed SEM-EDS and XRD analyses on- and off-defect… S.Bianco CMS Frascati - LNF Scientific Committee

  18. SEM / EDS analysis of defects inside irradiated RPC F peak Reference bakelite On-defect Peaks of defects Na peak On-defect Off-defect Peaks of NaF • Presence of Na in defects from bakelite • Preliminary XRD results show presence of NaF. http://arxiv.org/pdf/physics/0701014. S.Bianco CMS Frascati - LNF Scientific Committee

  19. CERN Closed Loop Gas System • We proposed to study presence of contaminants and their type ofaccumulation in the Closed Loop Gas system (same for CMS and ATLAS) • Current values in ISR Test Chambers decrease as the gas circulation changes from a closed to an open loop • We are coordinating a three-phase study of CL • Phase 1 September 06 - study contemporaneous to chamber testing. Limited by current values. • Phase 2 March 07 - Dedicated testing of DG’s and SG’s • Phase 3 ? - Dedicated testing at GIF possibly synergy with ATLAS S.Bianco CMS Frascati - LNF Scientific Committee

  20. CERN Closed Loop Gas system • All system components should be characterized: • Bakelite (all different types of bakelite) • Zeolite (all different zeolite filters) • Other filters based on Cu and Zn and oxides • Gas by means of a systematic sampling of the different parts during all of the system work phases S.Bianco CMS Frascati - LNF Scientific Committee

  21. Phase 1: ISR sampling September 2006 • Samples (unused, contaminated, regenerated) have been collected: • Purifiers: • Zeolite • Ni Al2O3; • Cu, Cu Zn • Pipes Cu • Neither oiled nor used bakelite • Unused bakelite oiled with graphite S.Bianco CMS Frascati - LNF Scientific Committee

  22. Table of analyses S.Bianco CMS Frascati - LNF Scientific Committee

  23. Different zeolite filters have been used : 3A, 5A. They differ in their grain size dimensions, framework pores amplitude and chemical composition 4A (4 Å, Na) 3A (3 Å, K) 5A (5 Å, Ca) Grain size distribution has been performed on zeolite filters : 3Å (25 gr) 1,4 mm (8 gr) 1 mm (17 gr) 5Å (25 gr) 2,8 mm (16 gr) 2 mm (9 gr) Zeolites characterization now used in CL S.Bianco CMS Frascati - LNF Scientific Committee

  24. Framework of Linde Type A zeolites 4A (4 Å, Na) 3A (3 Å, K) 5A (5 Å, Ca) Type A zeolites S.Bianco CMS Frascati - LNF Scientific Committee

  25. Linde Type A zeolite (Na96(H2O)216[Si96Al96O384] REFERENCE XRD performed at University of Rome “La Sapienza” on a sample of unused zeolite. On the right, the reference pattern for standard Linde Type A zeolite. S.Bianco CMS Frascati - LNF Scientific Committee

  26. Characterization of zeolite and other filters (Cu, Cu Zn; Ni, Al2O3) • Zeolites and otherfilters have been sampled (unused, contaminated, regenerated). On these samples, analyses have been performed: • Chemical analyses on major and trace elements, also sulphur, and carbon (graphitic, total and organic) • Ionic chromatography to analyze fluorine • XRD analyses to identify zeolite and to evaluate a possible crystalline structure of compounds, occurring after gas filtering The aims of these analyses are: • to characterize contaminants in filters • to identify their form (crystalline, in solution, amorphous) • to define the filters composition after regeneration S.Bianco CMS Frascati - LNF Scientific Committee

  27. Instrumentation available at University of Rome “La Sapienza” (Faculty of Engineering) • Stereomicroscope Leica Wild M10 • SEM Hitachi S2500, equipped with a Kevex X-ray Microanalizer. • XRD Philips X’Pert Plus diffraction system • HPLC ionic chromatography (High Performance Liquid Chromatography), made up of a Shimadzu LC-10ATvp pump and a column Shodex ICSI-50 4E, and a conductivity detector CDD-10Asp. • Roughness tester Mitutoyo Surftest • Sample preparation sets S.Bianco CMS Frascati - LNF Scientific Committee

  28. Traces of S and F in filters S.Bianco CMS Frascati - LNF Scientific Committee

  29. Closed loop Studies Summary • Closed loop filters detemined in 2001 at gif by looking at GC peaks • CAVE: Not everything bad for RPC shows up in a GC • Rigorous sampling in September 2006 • New materials • Used materials • Regenerated materials • A broad-spectrum analysis campaign (reference) to single out problems and to design more focussed analyses. • CMS Frascati provided specific expertise and instrumentation for the solution of a basic open problem - gas purifiers S.Bianco CMS Frascati - LNF Scientific Committee

  30. GAS GAIN MONITORING SYSTEM • A monitoring system of the RPC working point: • able to provide much faster and sensitive response than the CMS RPC system • Monitor efficiency and charge continuously - 1 hour cycles • 1% precision • Monitoring of charge and efficiences with cosmic rays (20 Hz/pads) in SGX5 gas building • Three sub-systems of 45x45 cm2 pads in the same telescope 1 Reference with clean open loop gas mix 2 Monitor “OUT” with close loop downstream of CMS RPCs 3 Monitor “IN” with close loop upstream of CMS RPCs • Multiplexed monitor on half-wheel gas line as future upgrade • In case work point changes • alarm goes on  action needed • Gas quality monitoring systems (GC,probes, etc) verify what the change of working point is due to. S.Bianco CMS Frascati - LNF Scientific Committee

  31. Gas Gain Monitor (conceptual design) USC5 UXC5 VENT RPC TRIG1 RPC TRIG2 Slow Ctrl GC, p/T/RH/Ph MONITOR VENT RPC PAD MON1 RPC PAD MON2 RPC PAD MON3 VENT RPC PAD MON4 RPC PAD MON5 CMS RPC PAD MON6 PURIFIERS REFERENCE half wheel lines VENT RPC PAD REF1 RPC PAD REF2 C2H2F4/SF6 /i-C4H10 /H2O VENT RPC TRIG3 RPC TRIG4 SGX Bldg S.Bianco CMS Frascati - LNF Scientific Committee

  32. Gas Gain Monitor (conceptual design) • Clean cosmic rays peak provide accurate monitor of working point • Three monitoring RPC with independent HV supply, on and off knee knee +200 -200 Ref.: S.Nuzzo 2006 10x10cm2 pad • Reading RPCs with two pads placed on both sides of detectors for timing, efficiency and charge S.Bianco CMS Frascati - LNF Scientific Committee

  33. GAIN MONITORING SYSTEM Foam READOUT PAD S.Bianco CMS Frascati - LNF Scientific Committee

  34. PROTOTYPE 45x45cm2 double-pad S.Bianco CMS Frascati - LNF Scientific Committee

  35. GAS GAIN MONITORING - DOUBLE PAD READOUT Pads 45x45cm2 positive and negative Cosmic ray event triggered by scintillation counters hodoscope DEVELOPING DIFFERENTIAL AMPLIFICATION SCHEME TO REDUCE COHERENT NOISE Sum pulse S.Bianco CMS Frascati - LNF Scientific Committee

  36. GAS GAIN MONITORING SYSTEM Gas mix used is 96.2% C2H2F4 / 3.5% Iso-C4H10 / 0.3% SF6 CMS RPC preliminary CMS RPC preliminary Charge distribution of avalanche from cosmic rays at voltages from 9.5kV to 10kV. Charge readout from 45x45cm2 pads fed to TEKTRONIX TDS5000 scope. S.Bianco CMS Frascati - LNF Scientific Committee

  37. Positive pad CMS RPC preliminary Negative pad GAS GAIN MONITORING SYSTEM Fitting charge distributions with truncated gaussians shows expected linear dependance of charge on HV (saturated avalanche). Peak is determined with a 1% accuracy for 104 event samples. S.Bianco CMS Frascati - LNF Scientific Committee

  38. AVALANCHE TO STREAMER TRANSITION Charge distribution on 45x45cm2 pad showing transition from avalanche to streamer. At t=0 standard gas mix contains 0.3% SF6, which is progressively removed. As SF6 is decreased, the streamer peak appears. 0.0% SF6 0.3% SF6 S.Bianco CMS Frascati - LNF Scientific Committee

  39. Our FEE options under test 1/6 Several amplification schemes are being explored. Even a simple passive sum of positive and negative pads and feeding to standard LRS612AMampli improves the S/N ratio. Type A0 - LM6172 - Dual High Speed, Low Power, Low Distortion Voltage Feedback Amplifiers Gain Bandwidth 100 MHz Slew Rate 3000 Volts/usec SupplyCurrent Per Channel 2.3 mA Supply Min 5.5 Volt Supply Max 36 Volt TRASFORMATORI (Zero centrale) Tipo A Ferrite Diametro 30mm spessore 6mmTipo B Ferrite Diametro 30mmspessore 12mmTipo C Miniatura diametro 6mm spessore 3mm Type A1 - Max 435 Differential, High Speed Op Amp Gain Bandwidth275 MHz Slew Rate 800 Volts/usec SupplyCurrent Per Channel 18 mA Supply Min 5 Volt Supply Max 12 Volt Type A2 - LMH6550 Differential, High Speed Op Amp Gain Bandwidth 400 MHz Slew Rate 3000 Volts/usec SupplyCurrent Per Channel 20 mA Supply Min 5 Volt Supply Max 12 Volt S.Bianco CMS Frascati - LNF Scientific Committee

  40. AMPLI Option Oscilloscopio Lecroy / Tektronix CMS RPC preliminary 10pF 100uH HV=9700V <- PEDESTAL 4uH 10nF S.Bianco CMS Frascati - LNF Scientific Committee

  41. RACKS LAYOUT IN SGX5 Only gas, no electronics 11 12 1 and 1/2 racks For gas gain monitor Gas quality here + piping,valves,GC ? Minimize signal cables lengths Lateral access S.Bianco CMS Frascati - LNF Scientific Committee

  42. SISTEMA PRONTO A GT2/5/07 S.Bianco CMS Frascati - LNF Scientific Committee

  43. Integration of Gas Gain Monitoring gaps with the CERN gas system S.Bianco CMS Frascati - LNF Scientific Committee

  44. Physics Studies • Channels with muon pairs (from J/psi, Upsilon(4s)), profiting of knowledge of RPC and DT muon detectors • Spectroscopy of Bc-->J/psi  • Mixing of Bs --> J/psi  • CPV in Bs --> J/psi  S.Bianco CMS Frascati - LNF Scientific Committee

  45. Papers 2006-2007 • Preprints and Conferences • S.Bianco on behalf of the CMS RPC Collaboration, “The gas gain monitoring system for the CMS RPC detector”, IEEE06, San Diego (USA) http://arxiv.org/pdf/physics/0701014. • C.Pucci “CMS RPC gas gain system”, Annual Congress of Italian Physical Society, Torino 2006 • D.Colonna “Use of FBG sensors for high precision silicon detectors”, Annual Congress of Italian Physical Society, Torino 2006 • M.Abbrescia et al., Proposal for a detailed study of Closed Loop… Frascati Preprint LNF 06/27 (IR) available at http://www.lnf.infn.it/sis/preprint/ • M.Caponero et al., “On the use of FBG sensors in CMS” Siena conference on adv. Detectors Nov 2006 (to appear on NIM) • A.Paolozzi et al., “Performances of FBG sensors for application at LHC experiments”, Vienna conference Feb 2007 (to appear on NIM) • S.Bianco et al., Omega-Like Fiber Bragg Grating Sensors as Position Monitoring Device: A Possible Pixel Position Detector in CMS? Frascati preprint LNF- 06/13(NT) • Masters and PhD Theses • C.Pucci Analisi dei materiali nelle RPC di CMS Frascati preprint LNF - 06 / 31(Thesis) • D.Colonna Applicazione dei sensori FBG in HEP e nelle strutture Marzo 2007 S.Bianco CMS Frascati - LNF Scientific Committee

  46. CONCLUSIONS • CMS Frascati was approved and funded by INFN in April 2006, just a little over one year after the BTeV cancellation • We have brought into the CMS RPC Collaboration important contributions in HEP detectors and materials science, and we now have a leading role in the gas studies • Cabling coordination (D.Colonna) • QC at production site • Gas purity and material studies, Gas gain monitoring system (S.Bianco) • CMS RPC is a unique playground for well-motivated students for both Physics and Engineering. • CMS Frascati benefits from excellent, well-motivated Engineering students. • The inflow of Physics students is more difficult, active search now in place to attack the topics of interest in physics analyses S.Bianco CMS Frascati - LNF Scientific Committee

  47. SPARE SLIDES S.Bianco CMS Frascati - LNF Scientific Committee