1. Pixel CO2 Cooling Status
Physics Department
Detector Technology Group
Pixel CO2 Cooling Status
João Noite PH-DT

2. CO2 Activities Review of the CMS Pixel cooling tube tests.
PSI CMS Pixel cooling Mock-up testing.
CO2 Full scale setup.
8 December 2009
João Noite PH-DT

3. CO2 Cooling Test Setup CO2 Blowsystem Schematics:
Tube Data and Test Conditions:
Stainless Steel 304T.
1.4 mm ID, 100 micron wall thickness.
5.5 m Length.
Applied heat load range from 35 to 220W.
Inlet Liquid Temperature from -20°C to 15°C.
CO2 Mass Flow from 0.5 to 2 g/s.
Dry air & temperature controlled environment.
Sensors and electrical power connections:
21 September 2018
João Noite PH-DT

4. Straight Tube Results @ -20°C
21 September 2018
João Noite PH-DT

5. Straight Tube Results @ -10°C
21 September 2018
João Noite PH-DT

6. Straight Tube Results @ 0°C
21 September 2018
João Noite PH-DT

7. PSI Bpix Cooling Mock-up Tests
Mock-up geometry data:
Stainless steel, 1.4 mm ID cooling tube.
5.5 m total length.
9x 180° tube bends with aprox. 7mm radius.
8x 54x18 mm SS heating plates.
Test conditions:
Simulated power load range from 50 to 200 W.
Inlet liquid temperature -20°C and -30°C.
CO2 mass flow from 1 to 1.5g/s.
21 September 2018
João Noite PH-DT

8. Sensor Positioning
PT100 sensors fixed with thermal glue in the cooling tube and SS heating plates.
Mock-up insulated and inserted in a feezer, tests run at cold temperature controlled environment.
Dry air is flushed into the freezer to avoid condensation. S1 S3 S5 S7 S9 S2 S4 S6 S8
S10 P1 P4 P7
P10 P2 P5 P8
P11 P3 P6 P9
P12
CO2 Out
CO2 In
21 September 2018
João Noite PH-DT

9. Dryout Inception
200W
160W
128W
106W
79W
53W

10. Dryout Inception
202W
162W
128W
108W
80W
53W

11. Full scale CO2 test setup
Cooling plant system based on the 2-Phase accumulator principle developed at NIKHEF.
CO2 pump loop cooling system.
2-Phase accumulator controling evaporation temperature.
R404 Chiller cooling accumulator and condensing CO2.
Pre-heater to set inlet vapor quality.
21 September 2018
João Noite PH-DT

12. P&I
21 September 2018
João Noite PH-DT

13. Main components selection
Pump:
LEWA LDC1 membrane pump with Watlow silicone rubber heater for pump oil.
Fittings:
Swagelok VCR fittings.
Swagelok tube fittings are also used in some exceptions.
Valves:
Swagelok Live-Loaded 40 Series ball valves. Operating temperature range from -53 to +65 C, rated pressure 172 bar and T-shaped drill pattern in the ball, in order to avoid trapped liquid.
Safety Valves:
Swagelok 6R3A proportional relief valve with EPDM O-ring for CO2 service.
Pulse damper:
Swagelok 500 cc Stainless Steel cylinder with Watlow electrical heater.
Heat Exchangers:
Reinforced SWEP heat exchanger to condense the CO2, allows low pressures on the primary side and high pressure on the secondary side.
Alfa Laval HEX specifically designed for CO2. Special brazed construction, maximum pressure 140 bar without additional reinforcement.
Accumulator:
Design and construction at NIKHEF, similar to LHCb-VELO accumulator.
Pre-Heater/Dummy Load Heater:
Glycol bath with electrical heaters.
21 September 2018
João Noite PH-DT

14. Design CMS-TEC cooling plant modified to support CO2 loop structure.
Design is finished, construction is in progress.
21 September 2018
João Noite PH-DT

15. Thanks for your attention
21 September 2018
João Noite PH-DT