Technical Forum Alice week Clemens Adler

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

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

3
TRD Chamber Design

• 540 (324) individual drift chambers (lt1450x1220
  mm²)
• Main components
• Radiator
• Driftchamber
• Padplane Backpanel
• Challenge for mechanical design
• Large Area, little Material
• high rigidity _at_ low weight
• (total 15 X0)

XeCO2(85/15)
4
Radiator

• 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)

• Production started mid Feb.
• 10 milestone reached end of July

5
Driftchamber/Wiring

• 3 cm Driftregion
• 2 wire planes
• Cathode 75µm Cu-Be
• Anode 25µm Au-W wire
• Moderate gas gain 5000
• Winding frame??

? Glueing
? Winding
6
Padplane

• 1.2 million pads
• Very large Area PCB
• good precision challenge

• Signalwires to be soldered to padplane
• Soldering will be done at IKF Frankfurt with
  dedicated soldering machine

7
Padplane test system

• 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

8
Back Panel

• 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

9
TRD in Space Frame

• 6 Layers, 5 colums per Supermodule
• Small-scale prototype supermodule at Hd
• Open issues
• Connection of services
• Final Engineering
• Plan concentrated effort by JINR DubnaPI Hd to
  settle design by end 2003

10
Milestones EDR/PRR

• EDR (Engineering Design Review) Sep. 2002
• Questions adressed
• Mechanical stability
• Gain uniformity, etc.
• Open questions
• Gain uniformity
• Leak rate (3 mbarl/h)

• PRR (Production Readiness Review) April 2003
• Question addressed
• Final mechanical design
• Prototype performance
• Production steps
• QA procedures
• Leak rate

11
Prototype measurements

• Gain non-uniformity lt 15
• tight requirement on backpanel flatness lt200µm
• Gain dependence of backpanel deformation by
  overpressure

• Gas tightness (driven by cost of Xenon)
• Goal lt3 mbarl/h
• Prototype lt0,1 mbarl/h (optimistic conditions)
• Gas interconnections need test in realistic
  conditions (several chamb.)

• Agrees well with Garfield calculations
  mechanical measurements

12
Test beam results
Signal vs. Drift time

• Testbeams at CERN and GSI

• ? TR-Spectrum
• Pion reject. factor gt100 ?

13
Test beam cont.

• Position resolution vs. Gain
• 300-400 µm (??)

• High precision dE/dx measurement ? NIM paper in
  prep.
• Space charge effects in drift chambers operated
  with Xe/CO2
• ? NIM paper in prep.

14
Detector Controls (DCS)

• HVLV
• Power supplies decided
• Minor Problems concerning communication (between
  electronics)

15
Cooling

• 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)

16
Services

• Little space within Supermodule, but all services
  fit
• Services towards TOF stay within envelope

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)

18
Gas system schedule

• Design practically ready
• Need to decide on final regulation segmentation
• PRR in October (following other gas system PRRs)

19
Chamber Production Sites

• Production sites
• Heidelberg
• Dubna
• GSI
• Bukarest
• (Münster)
• (Frankfurt)

• Philosophy Each site does everything
• to be seen...

20
Production QA

• 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.

21
Schedule

• 3 Supermodules 90 chambers have to be ready by
  1/2005
• production rate per site 2 chambers/week

Material delivery times

• Production start
• Heidelberg now
• Dubna Dec.
• Bukarest 1/2004
• GSI 4/2004

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