Petar Kesic TRAC Summer 2017
Cooling of CMS Detectors
CMS • C ompact M uon S olenoid • A general purpose detector at the Large Hadron Collider (LHC) at CERN. • One of 4 detection points around the LHC. • Acts like a camera (which detects photons) taking 3D “photographs” of particle collisions and recreating images of the collisions.
Inner / Silicon / Pixel Trackers High Granularity Calorimeters
• Detectors heat up because of energy released during detection and the operation of the electronic components. • In order to improve operation and prevent damage, it is necessary to transfer heat away from the components. • For performance and environmental reasons, CO2 has been chosen as the primary coolant. • The detector components are mounted on planks with CO2 cooling tubes embedded and then placed into the CMS. • It is necessary to keep the density and thickness of the planks low so that particles may continue to detectors which are farther away. • This poses certain design challenges. • Low density and thickness usually means lower strength, so a high strength material is needed. • Low density usually means poor heat transfer, so a material with exceptional heat transfer capability was needed. • Carbon fiber and carbon foam were chosen as the plank material because of their superior strength to density ratios and excellent heat transfer capabilities.
Performance of CO 2 and Carbon Fiber / Foam Planks • Why are we testing? • To assure that components are able to stay within acceptable operating temperatures when • the system is operating under standard conditions. • the system is operating outside of standard operating conditions. • What parameters are we looking at? • Delta T, Delta P , CO 2 Phase Changes, Thermal Runaway, etc.
CO 2 Phase Diagram
Different Detectors • Flat Barrel / PS Modules • 2S • HG Calorimeter
Flat Barrel
Power Calculations
2S
HG Calorimeter
HG Calorimeter Testing • Assisted Maral Alyari • Goal: Test the two phase CO2 cooling performance of FH cassette tubing with capillary at various angles around the beam pipe. • Stainless steel tubes are sandwiched between 4 layers of insulation foam. • CO2 temperature is monitored by RTDs placed on the tubing. • Voltage is applied to stainless steel tubing to mimic the heat load on the tubing. • Tubing acts as a heater. • The flow is monitored by a flowmeter placed at the inlet. • Two pressure transmitters are placed at the inlet and the outlet. • Attempted to cool various heat loads with minimum possible flow and lowest possible Δ P . • Data is analyzed by calibrating the RTD measurements to read the same temperature as the return CO 2 at 0 Watts.
270 deg. 0 deg.
Some HG Cal / CO 2 Results 00000 00000
Some HG Cal / CO 2 Results
2S Testing • Assisted Kirstyn Carlson • Goal: Test the water and ethylene glycol cooling performance of 2S Module. • Coolant is run through aluminum support structure. • Coolant temperature is monitored by RTDs placed at various locations on the module. • Voltage is applied to resistive heaters to mimic the heat load. • Attempted to cool various heat loads with minimum possible flow and lowest possible Δ P . • Data is analyzed by calibrating the RTD measurements to read the same temperature as the return fluid at 0 Watts.
Some 2S Data / Ethylene Glycol Cooling
FB / PS Modules Testing • Assisted Stefan Gruenendahl • Goal: Test the CO 2 cooling performance of FB Modules. • CO 2 is run through stainless steel tubing sandwiched in carbon fiber foam and sheets. • CO2 temperature is monitored by RTDs placed on the modules. • Voltage is applied to resistive heaters to mimic the heat loTubing acts as a heater. • The flow is monitored by a flowmeter placed at the inlet. • Attempted to cool various heat loads with minimum possible flow and lowest possible Δ P . • Data is analyzed by calibrating the RTD measurements to read the same temperature as the return CO 2 at 0 Watts.
FB / Modules on Plank
Some FB / Co 2 Cooling Results
Interactions / Meetings / Workshops / Lectures • Interactions with Fermilab personnel. • Interactions with other teachers. • Workshops • Lectures • Tours
Back-To-School • What can I take back to my students? • Personal growth. • “Real world” applications. • Ideas for lectures and demonstrations. • Inspiration to integrate particle physics into curriculum.
Acknowledgements • Special thanks to: • Stefan Gruenendahl • Maral Alyari • Kirstyn Carlson • Harry Cheung • and many others
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