TPC Field Cage Progress Report Project Schedule Technical Progress & Prototyping Contractual Matters ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Field Cage: Project Schedule ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Tests & Prototyping HV Temperature stabilization Construction material High ionization behavior (83Kr) Temperature stabilization Resistor chain cooling Construction material Compatibility and leaks Electrical network “From strip to central electrode” ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

High Voltage Stability History: Field cage was exposed to >16 x expected average charged particle intensity in CERES beam (~ 6000/cm2 s). Field cage was operated at 1.78 x nominal drift field (~700 V/cm) in pure CO2. Surface charge phenomena appearing at 60 kV (≥ 400 V/cm). Insulation gap safe at ≥ 100 kV. ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

High Intensity 83Kr Test Inject 83Kr with 300 MBq total intensity into field cage (May 2001) Separate tests for drift and insulation volume. ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Temperature Stability History: Require: DT everywhere ≤ 0.1 ºC Resistor rod produces 60 W waste heat. Liquid cooling (H2O) proven very efficient with negligible gradient inside rod but… H2O unsuitable at HV (dissociation), Inert liquids dangerous in case of leaks. New approach: Gas cooling ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Resistor Rod: Gas Cooling Unlike liquid cooling, DT inside rod always > 0.1 ºC. --> must insulate rod! Foam for test Double wall for ALICE. T [ºC] z [m] Ambient level 2.5 ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Gas Cooling: Results Inside of rod achieve Dtmin of 7 ºC with 20 m3/h of air: Tin = 16 ºC 7 ºC ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Gas Cooling: Results Outside of rod achieve required DT of ≤ 0.1 ºC within a few cm from rod: Numbers are given in units of 1/100 ºC; Blue numbers indicate zone around rod with DT < 0.1 ºC ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Material tests Drying DL/L [µm/m] T[ h] Macrolon Carbon Fiber Kevlar Fiber Glass Fiber Wet Leak test of full-size end plate sector with “CERES” gasket Humidity tests of FC material ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Voltage Divider: Central Electrode Focus on “stretched foil” version High modulus carbon-fiber frames NA48 Example ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Voltage Divider: Rods & Strips Ongoing prototyping of all rod types Resistor rod HV supply rod Laser rod Regular support rod Verification of strip tension and mounting scheme Vertical or horizontal? ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Tooling Modification of DELPHI support frame Needed for construction & assembly of FC Major handling tool for all operations Finished by end of 2001 ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Infrastructure: SXL2 Preparation of dedicated clean area for TPC assembly in LHC interaction region 2: Finished by December 2001 Clean zone in hall SXL2 ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Contracting: FC Cylinders First „Invitation to Tender“ (IT-2726) was launched on schedule in 2000, but... all offers (4) were above funding level. Changed scope of tender: Only production of individual parts (panels & flanges) Procurement by and assembly at CERN New tender (IT-2999) sent April 2001 6 months delay in schedule ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Contracting: End Plates First „Price Inquiry“ was made in 2000. Lowest bid exceeded funding by large factor. Try to achieve savings by… splitting production process (raw material, welding, machining), and design changes. New tenders to be launched this month only if expected savings materialize! Overall production delay ≥ 6 months. ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT

Contracts: Consequences for CERN Higher manpower load on CERN (TA2) Higher risks in terms of… technical failure, quality control, liability, warrenty! schedule slippage, capital loss. We expect to catch up on the baseline schedule during the internal assembly of the FC (2002/3). ALICE-LHCC Review May 14, 2001 Thomas C. Meyer/EP-AIT