10.9.03technical forum alice week clemens adler transition radiation detector status participating...

10.9.03 Technical Forum Alice week Clemens Adler

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


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


TRD Chamber Design

• 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)

XeCO2(85/15)


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


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


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


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


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


• 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


Milestones: EDR/PRR

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


Prototype measurements

• 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.)Agrees well with Garfield

calculations + mechanical measurements


Test beam results

Testbeams at CERN and GSI

TR-Spectrum

Pion reject. factor: >100

Signal vs. Drift time


Test beam cont.

• High precision dE/dx measurement NIM paper in prep.

• Space charge effects in drift chambers operated with Xe/CO2

NIM paper in prep.

• Position resolution vs. Gain:

~300-400 µm ()


Detector Controls (DCS)

HV+LV :

• Power supplies decided

• Minor Problems concerning communication (between electronics)


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)


Services

• Little space within Supermodule, but all services fit

• Services towards TOF stay within envelope


Gas system

Problems:

1) High cost gas (5 €/l of Xe)

2) High hydrostatic pressure over 7 m height

3) Light and large detectors, no big under- or over-pressures affordable

4) 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)


Gas system schedule

• Design practically ready– Need to decide on final regulation segmentation

• PRR in October (following other gas system PRRs)


Chamber Production Sites

• Production sites:– Heidelberg

– Dubna

– GSI

– Bukarest

– (Münster)

– (Frankfurt)

• Philosophy: „Each site does everything“to be seen...


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.


Schedule3 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

Material delivery times


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

10.9.03technical forum alice week clemens adler transition radiation detector status participating...

Documents

gas regeneration

gas recirculation

high cost gas

capillary gas inlet

gas system scheduledesign

auw wiremoderate gas

minimal fresh gas injection

drift time test beam