Transition Radiation Detector Status

1. Transition Radiation Detector Status Participating Institutions: Athens University, NIPNE Bukarest, JINR Dubna, IKF Frankfurt, GSI, PI Heidelberg, KIP Heidelberg, Uni Kaiserslautern, FH Köln, IKP Münster Technical Forum Alice week Clemens Adler

2. Overview • Chamber design: Body, Radiator,Padplane-/panel, • Reviews: EDR, PRR • Performance: EDR/PRR measurements, test beam results • Infrastructure: Detector Control/Gas system • Production: Sites, QA, Timescale Technical Forum Alice week Clemens Adler

3. 540 (324) individual drift chambers (<1450x1220 mm²) Main components: Radiator Driftchamber Padplane + Backpanel Challenge for mechanical design: Large Area, little Material: high rigidity @ low weight (total: 15% X0) TRD Chamber Design XeCO2(85/15) Technical Forum Alice week Clemens Adler

4. Produced at IKP Münster Transition radiation produced by PP-fibres (different foams and fibres tested) Rohacell core between Carbon fibre sheets (2 x 100 µm) Carbon laminate: 2 manufactures in the game (FACC Fischer, AIK Stesalit) Radiator • Production started mid Feb. • 10% milestone reached end of July Technical Forum Alice week Clemens Adler

5. 3 cm Driftregion 2 wire planes : Cathode: 75µm Cu-Be Anode: 25µm Au-W wire Moderate gas gain ~5000 Winding frame?? Driftchamber/Wiring  Glueing  Winding Technical Forum Alice week Clemens Adler

6. 1.2 million pads Very large Area PCB good precision: challenge Padplane • Signalwires to be soldered to padplane • Soldering will be done at IKF Frankfurt with dedicated soldering machine Technical Forum Alice week Clemens Adler

7. Checking for shorts/bad (solder-) connections after soldering (at IKF) Principle: Capacitance measurement between pads and ground plate Labview based system + electronics developed at PI Heidelberg Padplane test system Technical Forum Alice week Clemens Adler

8. Sandwich design build by FACC (Fischer): Honeycomb between Carbon fibre (100µm) Additional 2 mm Honeycomb on padplane side to reduce parasitic capacitance Gluing of padplane to 2mm honeycomb very sucessful Back Panel Technical Forum Alice week Clemens Adler

9. 6 Layers, 5 colums per ‚Supermodule‘ Small-scale prototype supermodule at Hd Open issues: Connection of services Final Engineering Plan: concentrated effort by JINR Dubna+PI Hd to settle design by end 2003 TRD in Space Frame Technical Forum Alice week Clemens Adler

10. EDR (Engineering Design Review) Sep. 2002 Questions adressed: Mechanical stability Gain uniformity, etc. Open questions: Gain uniformity Leak rate (3 mbar*l/h) PRR (Production Readiness Review): April 2003 Question addressed: Final mechanical design Prototype performance Production steps QA procedures Leak rate Milestones: EDR/PRR Technical Forum Alice week Clemens Adler

11. Gain non-uniformity < ±15% tight requirement on backpanel flatness <200µm Gain dependence of backpanel deformation by overpressure: Gas tightness (driven by cost of Xenon) Goal: <3 mbar*l/h Prototype: <0,1 mbar*l/h (optimistic conditions) Gas interconnections need test in realistic conditions (several chamb.) Prototype measurements • Agrees well with Garfield calculations + mechanical measurements Technical Forum Alice week Clemens Adler

12. Testbeams at CERN and GSI  TR-Spectrum Pion reject. factor: >100  Test beam results Signal vs. Drift time Technical Forum Alice week Clemens Adler

13. High precision dE/dx measurement  NIM paper in prep. Space charge effects in drift chambers operated with Xe/CO2  NIM paper in prep. Test beam cont. • Position resolution vs. Gain: • ~300-400 µm () Technical Forum Alice week Clemens Adler

14. HV+LV : Power supplies decided Minor Problems concerning communication (between electronics) Detector Controls (DCS) Technical Forum Alice week Clemens Adler

15. Tests at CERN last year: cooling pipe design fixed cooling seems to be no problem Final tests to be done at Heidelberg (all hardware is available) Cooling Technical Forum Alice week Clemens Adler

16. Little space within Supermodule, but all services fit Services towards TOF stay within envelope Services Technical Forum Alice week Clemens Adler

17. Gas system Problems: • High cost gas (5 €/l of Xe) • High hydrostatic pressure over 7 m height • Light and large detectors, no big under- or over-pressures affordable • Highly segmented detector (540 chambers) • Solutions: • Gas recirculation, minimal fresh gas injection (1) • Pressure regulation subdivided into (groups of) sectors (2,3) • Capillary gas inlet and two-stage outlet regulation for ensuring uniform flow and overpressure (2,3) • Gas regeneration for Xe recuperation (1,4) Technical Forum Alice week Clemens Adler

18. Gas system schedule • Design practically ready • Need to decide on final regulation segmentation • PRR in October (following other gas system PRRs) Technical Forum Alice week Clemens Adler

19. Production sites: Heidelberg Dubna GSI Bukarest (Münster) (Frankfurt) Philosophy: „Each site does everything“ to be seen... Chamber Production Sites Technical Forum Alice week Clemens Adler

20. During production: Tolerances Panel flatness Wiring Field cage Padplane After Production: Electrostatic tests Leak rate Gain (-uniformity) Gas system ready in Hd (Ar/CO2) X-Ray test stand (Dubna/Hd): Okt./Nov. 2003 Results stored in DCDB (work ongoing) Labview interface to DB Interface to HV, O2 meter etc. Production QA Technical Forum Alice week Clemens Adler

21. 3 Supermodules = 90 chambers have to be ready by 1/2005 production rate per site: 2 chambers/week Production start: Heidelberg: now Dubna: Dec. Bukarest: 1/2004 GSI: 4/2004 Schedule Material delivery times Technical Forum Alice week Clemens Adler

22. Summary • Chamber design is finalized • Prototype performance to spec. • TRD Chamber production is starting NOW (material is slowly arriving) at Hd • Other institutions getting ready for production Technical Forum Alice week Clemens Adler