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ALICE-LHCC Review May 14, 2001
Thomas C. Meyer/EP-AIT 1
TPC Field Cage Progress ReportTPC Field Cage Progress ReportTPC Field Cage Progress ReportTPC Field Cage Progress Report
Project ScheduleTechnical Progress &
PrototypingContractual Matters
ALICE-LHCC Review May 14, 2001
Thomas C. Meyer/EP-AIT 2
Field Cage: Project ScheduleField Cage: Project ScheduleField Cage: Project ScheduleField Cage: Project Schedule
ALICE-LHCC Review May 14, 2001
Thomas C. Meyer/EP-AIT 3
Tests & PrototypingTests & PrototypingTests & PrototypingTests & Prototyping
HV– 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 StabilityHigh Voltage StabilityHigh Voltage StabilityHigh 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 High Intensity 8383Kr TestKr TestHigh Intensity High Intensity 8383Kr TestKr 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 StabilityTemperature StabilityTemperature StabilityTemperature Stability
History:– Require:T 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 CoolingResistor Rod: Gas CoolingResistor Rod: Gas CoolingResistor Rod: Gas Cooling
Unlike liquid cooling, T inside rod always > 0.1 ºC.– --> must insulate rod!
Foam for test Double wall for ALICE.
T [ºC]
z [m]Ambient level2.5
ALICE-LHCC Review May 14, 2001
Thomas C. Meyer/EP-AIT 8
Gas Cooling: ResultsGas Cooling: ResultsGas Cooling: ResultsGas Cooling: Results Inside of rod achieve tmin of 7 ºC
with 20 m3/h of air:Air Temperature along the rod vs. Flow
0
5
10
15
20
25
30
35
40
45
0 2 4 6 8
Temperature [Celsius]
20m 3̂/h 15m 3̂/h 10m 3̂/h 5m 3̂/h
Gas Flow
Tin = 16 ºC
7 ºC
ALICE-LHCC Review May 14, 2001
Thomas C. Meyer/EP-AIT 9
Gas Cooling: ResultsGas Cooling: ResultsGas Cooling: ResultsGas Cooling: Results
Outside of rod achieve required T 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
T < 0.1 ºC
ALICE-LHCC Review May 14, 2001
Thomas C. Meyer/EP-AIT 10
Material testsMaterial testsMaterial testsMaterial tests
Drying
-250
-200
-150
-100
-50
0
50
-250
-200
-150
-100
-50
0
50
0 100 200 300 400 500
TEMPERATURE STABILIZATION : +/- 0.4 CPRECISION OF MEASUREMENT : +/- 10 μm
L/L
[µ
m/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 ElectrodeVoltage Divider: Central ElectrodeVoltage Divider: Central ElectrodeVoltage 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 & StripsVoltage Divider: Rods & StripsVoltage Divider: Rods & StripsVoltage 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
ToolingToolingToolingTooling
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: SXL2Infrastructure: SXL2Infrastructure: SXL2Infrastructure: 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 CylindersContracting: FC CylindersContracting: FC CylindersContracting: 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 PlatesContracting: End PlatesContracting: End PlatesContracting: 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 CERNContracts: Consequences for CERNContracts: Consequences for CERNContracts: 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).