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

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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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