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September 17th 2011, JPS autumn meeting @ Hirosaki University

Commissioning Status of the Drift Chamber for a Di-Muon Spectrometer at the E906/ SeaQuest Experiment at Fermilab. 東工大 ， 理研 A ，高エネ機構 B ， 山形大 C Florian Sanftl ， 後藤雄二 A ，澤田真也 B ， 柴田利 明， 竹内 信 太郎， 竹谷篤 A ，中野 健一， 宮坂 翔，宮地義之 他 E906 / SeaQuest Collaboration.

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September 17th 2011, JPS autumn meeting @ Hirosaki University

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  1. Commissioning Status of the Drift Chamber for a Di-Muon Spectrometer at the E906/SeaQuest Experiment at Fermilab 東工大，理研A，高エネ機構B，山形大CFlorian Sanftl，後藤雄二A，澤田真也B，柴田利明，竹内信太郎，竹谷篤A，中野健一，宮坂翔，宮地義之他 E906 / SeaQuest Collaboration September 17th 2011, JPS autumnmeeting@ Hirosaki University

  2. Outline • SeaQuest: Physics Motivation • SeaQuest: Spectrometer • Drift Chamber(s): Design and Specifications • Experimental Setup @ Tokyo Tech • Results: Turn on curve • Track Reconstruction Algorithm • Results: XT-Curve • Conclusion Florian Sanftl @ JPS autumn meeting 2011

  3. xtarget xbeam SeaQuest: Drell-Yan & Anti-Quarks in a Nutshell Sawada-san’s talk: 18pSL-6 Beam Energy:120 GeV/ 800 GeV E906 Spect. Monte Carlo Detector acceptance chooses xtarget and xbeam: • Fixed target -> high xF = xbeam – xtarget • Valence Beam quarks at high-x. • Sea Target quarks at low/intermediate-x. • Drell Yan as a perfect tool to probe Anti-Quarks Florian Sanftl @ JPS autumn meeting 2011

  4. 4.9m SeaQuest: Spectrometer Station 4: Hodoscope array Prop tube tracking Philosophy: Redo, Reuse, Recycle Station 2 and 3: Hodoscope array Drift Chamber tracking Station 1: Hodoscope array MWDC tracking Solid IronFocusing Magnet, Hadron absorber and beam dump Mom. Meas. (KTeV Magnet) St. 3Plus: NEW from E906J Hadron Absorber (Iron Wall) 25m Liquid H2, d2, and solid targets (e.g. Fe, Ca, C) Drawing: T. O’Connor and K. Bailey Florian Sanftl @ JPS autumn meeting 2011

  5. The New Station 3 Drift Chamber(s) • General Performance requirements • Detection Area:1.6 m (vertical) x 2.2 m (horizontal) • 6 Active layers:U/U’ (+14°), X/X’ (0°), V/V’ (-14°) • Position resolution: < 400 μm per plane • Gas Selection: • For now: Argon:CO2 (80:20) V’ V X’ X U’ U Florian Sanftl @ JPS autumn meeting 2011

  6. The New Station 3 Drift Chamber(s) • Cell Structure • Cell width& height 20 mm • Wire spacing 10 mm • Diameter sense wire (Au-W) 30 μm, others (Au-CuBe) 80 μm • Performance Parameters • Gas-gain ~4.0E5 • Drift velocity 3-6 cm / μsec (Ar:CO2) Florian Sanftl @ JPS autumn meeting 2011

  7. The New Station 3 Drift Chamber(s) 1.7 m 3.5 m Florian Sanftl @ JPS autumn meeting 2011

  8. Test Chamber: Setup Cosmic 1.7 m Scinti.PMT Discri. Drift Chamber ASDQ card Level Shifter Board LVDS To NIM Stop TDC PC 0.7 m Start Scinti. + PMT Discri. Coincidence • Read-Out Electronics same as SeaQuest • ASDQ = Amplifier, Signal Shaper, Discriminator &Charge Injector • Controlled by Level Shifter Board (Set thresholds, Ethernet access etc. pp.) • 48 Channels (= 6 x 8) • Coincidence as Trigger Start, Common Start Setup • Cosmic Rays are used  no defined incident angle (range of ~10°) Florian Sanftl @ JPS autumn meeting 2011

  9. Single Layer DetectionEfficiencies • Results: • The Single layer efficiency increases with increasing High Voltage • Single Layer efficiency reaches 95±5%@ -2.65kV • Uncertainties are investigated (accidental coincidence) • Discriminator Threshold on MAX • Some conclusions: • Some little space for improvement • (Rough estimate for track reconstruction eff. 74.4% for 5 hits minimum requirement) Florian Sanftl @ JPS autumn meeting 2011

  10. Tracking: Algorithm Reconstructed track Projected DCA Accepted Hits • Selections & definitions: • Drift time = TDC – t0 • Same t0 for all channels • Drift time window: 520ns • Accept event when4 < Number of hits < 11per layer Florian Sanftl @ JPS autumn meeting 2011

  11. Tracking: PreliminaryResults • XT extraction: • 1st Iteration • Extracted curve agrees well with input curve within uncertainties • Still too little statistics from the edge of cell • Deviation simulation/measurement: • Green bands is width of the projections • Those are constant over a wide T range • Band: Superposition of uncertainties from hit reconstruction and track reconstruction • Disentanglement of both effects is investigated Florian Sanftl @ JPS autumn meeting 2011

  12. Conclusionsand Outlook • SeaQuest is a fixed target experiment at Fermilab • SeaQuest is going to measure the flavor asymmetry of the nucleon sea • Commissioning is going to start in autumn 2011 • The Japanese collaboration constructed and built a new DC • In order to prepare for the beam we setup the software package based in our test chamber in Tokyo • We reported on the first extraction of an XT curve based on cosmic data • The Tracking algorithm is working properly • We have to move forward a complete calibration • The uncertainties have to be better understood and investigated Florian Sanftl @ JPS autumn meeting 2011

  13. Backup: SomeGeometry U & U’ X & X’ Sense wire edge TDC data Florian Sanftl @ JPS autumn meeting 2011

  14. Backup: TDC distributions • Observation • Discrepancy between simulation and measurement • Account for that in the T2Xconversion Simulated result Measured result 250 ns 350 ns Florian Sanftl @ JPS autumn meeting 2011

  15. Backup: GasGain • R : ±5% • : ±15% ＋5% • : ＋15% • : ±10% • : ±25% • Density of gas : ±5% • Diameter of sense wire (±10%) : ±80% < Systematic errors> Total : • Note: The effect of the diameter of sense wires on the gas gain is large. • The gas gain was • The gas gain increases when the HV value increases. • The measured results and the simulated results agree in order of magnitude. • The measured value is about twice the simulated value. • The measured result shows the better gas gain in our measurement. • The measured and the simulated results are consistent within errors <Estimated change in gas gain> Diameter of sense wire : 30 μm 29.4 μm (): 110% 28.5 μm (): 130% 27.0 μm (): 180% 26.5 μm (): 200% 25.0 μm (): 290% Florian Sanftl @ JPS autumn meeting 2011

  16. Backup: Tracking Algorithm v2 • Cuts: • TDC Cuts • Number of events cuts • Sam t0 for all channels • 5 layers • … more Algo details • Results: • Good agreement • More iterations • More data • Tracking efficiencies • Position resolution Florian Sanftl @ JPS autumn meeting 2011

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